1
|
Mengmeng Y, Yongxing S, Linggang K, Jiachen L. Study on the effect of volatile organic compounds on the treatment of high-salt wastewater by low-temperature evaporation. ENVIRONMENTAL TECHNOLOGY 2024:1-18. [PMID: 39128844 DOI: 10.1080/09593330.2024.2388313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Accepted: 07/26/2024] [Indexed: 08/13/2024]
Abstract
High-salinity wastewater, owing to its intricate composition and challenging treatment requirements, poses a significant hurdle in water environmental governance. In this study, low-temperature evaporation technology is used to tackle wastewater containing the volatile organic compound such as N,N-dimethylacetamide (DMAC). Utilisation of comprehensive approaches involving experimental testing, mathematical modelling, and Aspen Plus software simulations, The influence of DMAC on evaporation efficiency is researched through the following factors which encompassing its effects on boiling point elevation, partial molar activation energy, and the formation of by-products. Additionally, the comparation of the impact of temperature, ionic strength, intermolecular interactions on the evaporation rate and the concentration of the volatile component DMAC in the condensate is also conducted in this study. After conducting a multiple linear regression analysis of evaporation efficiency using the Statistical Product and Service Solutions (SPSS) tool, it was discovered that temperature serves as the primary determinant influencing the evaporation rate. Additionally, ionic strength impacts solution viscosity, intermolecular interactions, and saturated vapour pressure by altering the intermolecular forces, thereby indirectly influencing both the evaporation rate and the quality of condensate water. The comparative analysis of single-effect and double-effect evaporation indicates that the optimal operating condition for double-effect evaporation yields an evaporation rate of 70%, with a remarkable 88% reduction in steam consumption compared to single one. Based on heat and mass balance principles, the mathematical model for double-effect evaporation is established to offer crucial data support for practical industrial applications.
Collapse
Affiliation(s)
- Yin Mengmeng
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, People's Republic of China
| | - Shi Yongxing
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, People's Republic of China
| | - Kong Linggang
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, People's Republic of China
| | - Liu Jiachen
- School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan, People's Republic of China
| |
Collapse
|
2
|
Sun Q, Chen YN, Liu YZ. The Effects of External Interfaces on Hydrophobic Interactions I: Smooth Surface. Molecules 2024; 29:3128. [PMID: 38999080 PMCID: PMC11243484 DOI: 10.3390/molecules29133128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2024] [Revised: 06/25/2024] [Accepted: 06/28/2024] [Indexed: 07/14/2024] Open
Abstract
External interfaces, such as the air-water and solid-liquid interfaces, are ubiquitous in nature. Hydrophobic interactions are considered the fundamental driving force in many physical and chemical processes occurring in aqueous solutions. It is important to understand the effects of external interfaces on hydrophobic interactions. According to the structural studies on liquid water and the air-water interface, the external interface primarily affects the structure of the topmost water layer (interfacial water). Therefore, an external interface may affect hydrophobic interactions. The effects of interfaces on hydrophobicity are related not only to surface molecular polarity but also to the geometric characteristics of the external interface, such as shape and surface roughness. This study is devoted to understanding the effects of a smooth interface on hydrophobicity. Due to hydrophobic interactions, the solutes tend to accumulate at external interfaces to maximize the hydrogen bonding of water. Additionally, these can be demonstrated by the calculated potential mean forces (PMFs) using molecular dynamic (MD) simulations.
Collapse
Affiliation(s)
- Qiang Sun
- Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, The School of Earth and Space Sciences, Peking University, Beijing 100871, China (Y.-Z.L.)
| | | | | |
Collapse
|
3
|
Hanifi K, Scrosati PM, Konermann L. MD Simulations of Peptide-Containing Electrospray Droplets: Effects of Parameter Settings on the Predicted Mechanisms of Gas Phase Ion Formation. J Phys Chem B 2024; 128:5973-5986. [PMID: 38864851 DOI: 10.1021/acs.jpcb.4c01241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Electrospray ionization (ESI) mass spectrometry is widely used for interrogating peptides, proteins, and other biomolecular analytes. A growing number of laboratories use molecular dynamics (MD) simulations for uncovering ESI mechanisms by modeling the behavior of highly charged nanodroplets. The outcome of any MD simulation depends on certain assumptions and parameter settings, and it is desirable to optimize these factors by benchmarking computational data against experiments. Unfortunately, benchmarking of ESI simulations is difficult because experimentally generated gaseous ions do not generally retain any features that would reveal their formation pathway [e.g., the charged residue mechanism (CRM) or the ion evaporation mechanism (IEM)]. Here, we tackle this problem by examining the effects of various MD settings on the ESI behavior of the 9-residue peptide bradykinin in acidic aqueous droplets. Several parameters were found to significantly affect the kinetic competition between peptide IEM and CRM. By systematically probing the droplet behavior, we uncovered problems associated with certain settings, including peptide/solvent temperature imbalances, unexpected peptide deceleration during IEM, and a dependence of the ESI mechanism on the water model. We also noted different simulation outcomes for different force fields. On the basis of comprehensive tests, we propose a set of "best practice" parameter settings for MD simulations of ESI droplets. The strategies used here should be transferable to other types of droplet simulations, paving the way toward a more solid understanding of ESI mechanisms.
Collapse
Affiliation(s)
- Kasra Hanifi
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Pablo M Scrosati
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| |
Collapse
|
4
|
Konermann L, Liu Z, Haidar Y, Willans MJ, Bainbridge NA. On the Chemistry of Aqueous Ammonium Acetate Droplets during Native Electrospray Ionization Mass Spectrometry. Anal Chem 2023; 95:13957-13966. [PMID: 37669319 DOI: 10.1021/acs.analchem.3c02546] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Ammonium acetate (NH4Ac) is a widely used solvent additive in native electrospray ionization (ESI) mass spectrometry. NH4Ac can undergo proton transfer to form ammonia and acetic acid (NH4+ + Ac- → NH3 + HAc). The volatility of these products ensures that electrosprayed ions are free of undesired adducts. NH4Ac dissolution in water yields pH 7, providing "physiological" conditions. However, NH4Ac is not a buffer at pH 7 because NH4+ and Ac- are not a conjugate acid/base pair (Konermann, L. J. Am. Soc. Mass Spectrom. 2017, 28, 1827-1835.). In native ESI, it is desirable that analytes experience physiological conditions not only in bulk solution but also while they reside in ESI droplets. Little is known about the internal milieu of NH4Ac-containing ESI droplets. The current work explored the acid/base chemistry of such droplets, starting from a pH 7 analyte solution. We used a two-pronged approach involving evaporation experiments on bulk solutions under ESI-mimicking conditions, as well as molecular dynamics simulations using a newly developed algorithm that allows for proton transfer. Our results reveal that during droplet formation at the tip of the Taylor cone, electrolytically generated protons get neutralized by Ac-, making NH4+ the net charge carriers in the weakly acidic nascent droplets. During the subsequent evaporation, the droplets lose water as well as NH3 and HAc that were generated by proton transfer. NH3 departs more quickly because of its greater volatility, causing the accumulation of HAc. Together with residual Ac-, these HAc molecules form an acetate buffer that stabilizes the average droplet pH at 5.4 ± 0.1, as governed by the Henderson-Hasselbalch equation. The remarkable success of native ESI investigations in the literature implies that this pH drop by ∼1.6 units relative to the initially neutral analyte solution can be tolerated by most biomolecular analytes on the short time scale of the ESI process.
Collapse
Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Zeyuan Liu
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Yousef Haidar
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Mathew J Willans
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Nicholas A Bainbridge
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
5
|
Pandey PK, Chandra A. Mechanism, Kinetics, and Potential of Mean Force of Evaporation of Water from Aqueous Sodium Chloride Solutions of Varying Concentrations. J Phys Chem B 2023; 127:4602-4612. [PMID: 37163726 DOI: 10.1021/acs.jpcb.2c09004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The mechanism, kinetics, and potential of mean force of evaporation of water from aqueous NaCl solutions are investigated through both unbiased molecular dynamics simulations and also biased simulations using the umbrella sampling method. The results are obtained for aqueous solutions of three different NaCl concentrations ranging from 0.6 to 6.0 m and also for pure water. The rate of evaporation is found to decrease in the presence of ions. It is found that the process of evaporation of a surface water molecule from ionic solutions can be triggered through its collision with another water or chloride ion. Such collisions provide the additional kinetic energy that is required for evaporation. However, when the collision takes place with a Cl- ion, the evaporation of the escaping water also involves a collision with water in the vicinity of the ion at the same time along with the ion-water collision. These two collisions together provide the required kinetic energy for escape of the evaporating water molecule. Thus, the mechanism of evaporation process of ionic solutions can be more complex than that of pure water. The potential of mean force (PMF) of evaporation is found to be positive and it increases with increasing ion concentration. Also, no barrier in the PMF is found to be present for the condensation of water from vapor phase to the surfaces of the solutions. A detailed analysis of the unsuccessful evaporation attempts by surface water molecules is also made in the current study.
Collapse
Affiliation(s)
- Prashant Kumar Pandey
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, India 208016
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, India 208016
| |
Collapse
|
6
|
Hou D, Wang G, Gao J, Luo KH. Molecular dynamics study on evaporation of metal nitrate-containing nanodroplets in flame spray pyrolysis. NANOSCALE 2023; 15:5877-5890. [PMID: 36876507 DOI: 10.1039/d3nr00060e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Flame spray pyrolysis (FSP) provides an advantageous synthetic route for LiNi1-x-yCoxMnyO2 (NCM) materials, which are one of the most practical and promising cathode materials for Li-ion batteries. However, a detailed understanding of the NCM nanoparticle formation mechanisms through FSP is lacking. To shed light on the evaporation of NCM precursor droplets in FSP, in this work, we employ classical molecular dynamics (MD) simulations to explore the dynamic evaporation process of nanodroplets composed of metal nitrates (including LiNO3, Ni(NO3)2, Co(NO3)2, and Mn(NO3)2 as solutes) and water (as solvent) from a microscopic point of view. Quantitative analysis on the evaporation process has been performed by tracking the temporal evolution of key features including the radial distribution of mass density, the radial distribution of number density of metal ions, droplet diameter, and coordination number (CN) of metal ions with oxygen atoms. Our MD simulation results show that during the evaporation of an MNO3-containing (M = Li, Ni, Co, or Mn) nanodroplet, Ni2+, Co2+, and Mn2+ will precipitate on the droplet surface, forming a solvent-core-solute-shell structure; whereas the distribution of Li+ within the evaporating LiNO3-containing droplet is more even due to the high diffusivity of Li+ compared with other metal ions. For the evaporation of a Ni(NO3)2- or Co(NO3)2-containing nanodroplet, the temporal evolution of the CN of M-OW (M = Ni or Co; OW represents O atoms from water) suggests a "free H2O" evaporation stage, during which both CN of M-OW and CN of M-ON are unchanged with time. Evaporation rate constants at various conditions are extracted by making analogy to the classical D2 law for droplet evaporation. Unlike Ni or Co, CN of Mn-OW keeps changing with time, yet the temporal evolution of the squared droplet diameter indicates the evaporation rate for a Ni(NO3)2-, Co(NO3)2-, or Mn(NO3)2-containing droplet is hardly affected by the different types of the metal ions.
Collapse
Affiliation(s)
- Dingyu Hou
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
| | - Geng Wang
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
| | - Jingqi Gao
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
| | - Kai H Luo
- Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE, UK.
| |
Collapse
|
7
|
Decoupling thermal effects and possible non-thermal effects of microwaves in vacuum evaporation of glucose solutions. J FOOD ENG 2023. [DOI: 10.1016/j.jfoodeng.2022.111257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
8
|
Hari Govindha A, Katre P, Balusamy S, Banerjee S, Sahu KC. Counter-Intuitive Evaporation in Nanofluids Droplets due to Stick-Slip Nature. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:15361-15371. [PMID: 36459485 DOI: 10.1021/acs.langmuir.2c02590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
We experimentally investigate the evaporation characteristics of a sessile ethanol droplet containing Al2O3 and Cu nanoparticles of sizes 25 and 75 nm on a heated substrate using shadowgraphy and infrared imaging techniques. Our results demonstrate that the droplet contact line dynamics resulting from the presence of various nanoparticles plays a dominant role in the evaporation process. This is in contrast to the widely held assumption that the enhanced evaporation rate observed in sessile nanofluid droplets is due to the higher thermal conductivity of the added nanoparticles. We observe that even though the thermal conductivity of Al2O3 is an order of magnitude lower than that of Cu, droplets containing 25-nm-sized Al2O3 exhibit pinned contact line dynamics and evaporate much more rapidly than droplets containing Cu nanoparticles of both sizes and 75 nm Al2O3 nanoparticles that exhibit stick-slip behavior. We also found that the droplets with different nanoparticles display distinct thermal patterns due to the difference in contact line behavior, which alters the heat transfer inside the droplets. We establish this counter-intuitive observation by analyzing the temporal variations of the perimeter, free surface area, and deposition patterns on the substrate.
Collapse
Affiliation(s)
- A Hari Govindha
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| | - Pallavi Katre
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| | - Saravanan Balusamy
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| | - Sayak Banerjee
- Department of Mechanical and Aerospace Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| | - Kirti Chandra Sahu
- Department of Chemical Engineering, Indian Institute of Technology Hyderabad, Kandi, Hyderabad 502284, Telangana, India
| |
Collapse
|
9
|
Konermann L, Haidar Y. Mechanism of Magic Number NaCl Cluster Formation from Electrosprayed Water Nanodroplets. Anal Chem 2022; 94:16491-16501. [DOI: 10.1021/acs.analchem.2c04141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Yousef Haidar
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
10
|
Aliyari E, Konermann L. Formation of Gaseous Peptide Ions from Electrospray Droplets: Competition between the Ion Evaporation Mechanism and Charged Residue Mechanism. Anal Chem 2022; 94:7713-7721. [PMID: 35587384 DOI: 10.1021/acs.analchem.2c01355] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The transfer of peptide ions from solution into the gas phase by electrospray ionization (ESI) is an integral component of mass spectrometry (MS)-based proteomics. The mechanisms whereby gaseous peptide ions are released from charged ESI nanodroplets remain unclear. This is in contrast to intact protein ESI, which has been the focus of detailed investigations using molecular dynamics (MD) simulations and other methods. Under acidic liquid chromatography/MS conditions, many peptides carry a solution charge of 3+ or 2+. Because of this pre-existing charge and their relatively small size, prevailing views suggest that peptides follow the ion evaporation mechanism (IEM). The IEM entails analyte ejection from ESI droplets, driven by electrostatic repulsion between the analyte and droplet. Surprisingly, recent peptide MD investigations reported a different behavior, that is, the release of peptide ions via droplet evaporation to dryness which represents the hallmark of the charged residue mechanism (CRM). Here, we resolved this conundrum by performing MD simulations on a common model peptide (bradykinin) in Rayleigh-charged aqueous droplets. The primary focus was on pH 2 conditions (bradykinin solution charge = 3+), but we also verified that our MD strategy captured pH-dependent charge state shifts seen in ESI-MS experiments. In agreement with earlier simulations, we found that droplets with initial radii of 1.5-3 nm predominantly release peptide ions via the CRM. In contrast, somewhat larger radii (4-5 nm) favor IEM behavior. It appears that these are the first MD data to unequivocally demonstrate the viability of peptide IEM events. Electrostatic arguments can account for the observed droplet size dependence. In summary, both CRM and IEM can be operative in peptide ESI-MS. The prevalence of one over the other mechanism depends on the droplet size distribution in the ESI plume.
Collapse
Affiliation(s)
- Elnaz Aliyari
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
11
|
Konermann L, Kim S. Grotthuss Molecular Dynamics Simulations for Modeling Proton Hopping in Electrosprayed Water Droplets. J Chem Theory Comput 2022; 18:3781-3794. [PMID: 35544700 DOI: 10.1021/acs.jctc.2c00001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Excess protons in water exhibit unique transport properties because they can rapidly hop along H-bonded water wires. Considerable progress has been made in unraveling this Grotthuss diffusion mechanism using quantum mechanical-based computational techniques. Unfortunately, high computational cost tends to restrict those techniques to small systems and short times. Molecular dynamics (MD) simulations can be applied to much larger systems and longer time windows. However, standard MD methods do not permit the dissociation/formation of covalent bonds, such that Grotthuss diffusion cannot be captured. Here, we bridge this gap by combining atomistic MD simulations (using Gromacs and TIP4P/2005 water) with proton hopping. Excess protons are modeled as hydronium ions that undergo H3O+ + H2O → H2O + H3O+ transitions. In accordance with ab initio MD data, these Grotthuss hopping events are executed in "bursts" with quasi-instantaneous hopping across one or more waters. The bursts are separated by regular MD periods during which H3O+ ions undergo Brownian diffusion. The resulting proton diffusion coefficient agrees with the literature value. We apply this Grotthuss MD technique to highly charged water droplets that are in a size regime encountered during electrospray ionization (5 nm radius, ∼17,000 H2O). The droplets undergo rapid solvent evaporation and occasional H3O+ ejection, keeping them at ca. 81% of the Rayleigh limit. The simulated behavior is consistent with phase Doppler anemometry data. The Grotthuss MD technique developed here should be useful for modeling the behavior of various proton-containing systems that are too large for high-level computational approaches. In particular, we envision future applications related to electrospray processes, where earlier simulations used metal cations while in reality excess protons dominate.
Collapse
Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Scott Kim
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
12
|
Bertier P, Lavy L, Comte D, Feketeová L, Salbaing T, Azuma T, Calvo F, Farizon B, Farizon M, Märk TD. Energy Dispersion in Pyridinium-Water Nanodroplets upon Irradiation. ACS OMEGA 2022; 7:10235-10242. [PMID: 35382340 PMCID: PMC8973082 DOI: 10.1021/acsomega.1c06842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
Postirradiation dissociation of molecular clusters has been mainly studied assuming energy redistribution in the entire cluster prior to the dissociation. Here, the evaporation of water molecules from out-of-equilibrium pyridinium-water cluster ions was investigated using the recently developed correlated ion and neutral time-of-flight (COINTOF) mass spectrometry technique in combination with a velocity-map imaging (VMI) device. This special setup enables the measurement of velocity distributions of the evaporated molecules upon high-velocity collisions with an argon atom. The distributions measured for pyridinium-water cluster ions are found to have two distinct components. Besides a low-velocity contribution, which corresponds to the statistical evaporation of water molecules after nearly complete redistribution of the excitation energy within the clusters, a high-velocity contribution is also found in which the molecules are evaporated before the energy redistribution is complete. These two different evaporation modes were previously observed and described for protonated water cluster ions. However, unlike in the case of pure water clusters, the low-velocity part of the distributions for pyridinium-doped water clusters is itself composed of two distinct Maxwell-Boltzmann distributions, indicating that evaporated molecules originate in this case from out-of-equilibrium processes. Statistical molecular dynamics simulations were performed to (i) understand the effects caused in the ensuing evaporation process by the various excitation modes at different initial cluster constituents and to (ii) simulate the distributions resulting from sequential evaporations. The presence of a hydrophobic impurity in water clusters is shown to impact water molecule evaporation due to the energy storage in the internal degrees of freedom of the impurity.
Collapse
Affiliation(s)
- Paul Bertier
- Université
de Lyon, Université Claude Bernard Lyon1, CNRS, IP2I Lyon/IN2P3,
UMR5822, F-69622, Villeurbanne, France
- Atomic,
Molecular & Optics (AMO) Physics Laboratory, RIKEN Cluster for Pioneering Research, 351-0198 Saitama, Japan
| | - Léo Lavy
- Université
de Lyon, Université Claude Bernard Lyon1, CNRS, IP2I Lyon/IN2P3,
UMR5822, F-69622, Villeurbanne, France
| | - Denis Comte
- Université
de Lyon, Université Claude Bernard Lyon1, CNRS, IP2I Lyon/IN2P3,
UMR5822, F-69622, Villeurbanne, France
- Institut
für Ionenphysik und Angewandte Physik, Leopold Franzens Universität Innsbruck, 6020 Innsbruck, Austria
| | - Linda Feketeová
- Université
de Lyon, Université Claude Bernard Lyon1, CNRS, IP2I Lyon/IN2P3,
UMR5822, F-69622, Villeurbanne, France
| | - Thibaud Salbaing
- Université
de Lyon, Université Claude Bernard Lyon1, CNRS, IP2I Lyon/IN2P3,
UMR5822, F-69622, Villeurbanne, France
| | - Toshiyuki Azuma
- Atomic,
Molecular & Optics (AMO) Physics Laboratory, RIKEN Cluster for Pioneering Research, 351-0198 Saitama, Japan
| | - Florent Calvo
- Université
Grenoble Alpes, CNRS, LIPhy, F-38000 Grenoble, France
| | - Bernadette Farizon
- Université
de Lyon, Université Claude Bernard Lyon1, CNRS, IP2I Lyon/IN2P3,
UMR5822, F-69622, Villeurbanne, France
| | - Michel Farizon
- Université
de Lyon, Université Claude Bernard Lyon1, CNRS, IP2I Lyon/IN2P3,
UMR5822, F-69622, Villeurbanne, France
| | - Tilmann D. Märk
- Institut
für Ionenphysik und Angewandte Physik, Leopold Franzens Universität Innsbruck, 6020 Innsbruck, Austria
| |
Collapse
|
13
|
Aliyari E, Konermann L. Atomistic Insights into the Formation of Nonspecific Protein Complexes during Electrospray Ionization. Anal Chem 2021; 93:12748-12757. [PMID: 34494821 DOI: 10.1021/acs.analchem.1c02836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Native electrospray ionization (ESI)-mass spectrometry (MS) is widely used for the detection and characterization of multi-protein complexes. A well-known problem with this approach is the possible occurrence of nonspecific protein clustering in the ESI plume. This effect can distort the results of binding affinity measurements, and it can even generate gas-phase complexes from proteins that are strictly monomeric in bulk solution. By combining experiments and molecular dynamics (MD) simulations, the current work for the first time provides detailed insights into the ESI clustering of proteins. Using ubiquitin as a model system, we demonstrate how the entrapment of more than one protein molecule in an ESI droplet can generate nonspecific clusters (e.g., dimers or trimers) via solvent evaporation to dryness. These events are in line with earlier proposals, according to which protein clustering is associated with the charged residue model (CRM). MD simulations on cytochrome c (which carries a large intrinsic positive charge) confirmed the viability of this CRM avenue. In addition, the cytochrome c data uncovered an alternative mechanism where protein-protein contacts were formed early within ESI droplets, followed by cluster ejection from the droplet surface. This second pathway is consistent with the ion evaporation model (IEM). The observation of these IEM events for large protein clusters is unexpected because the IEM has been thought to be associated primarily with low-molecular-weight analytes. In all cases, our MD simulations produced protein clusters that were stabilized by intermolecular salt bridges. The MD-generated charge states agreed with experiments. Overall, this work reveals that ESI-induced protein clustering does not follow a tightly orchestrated pathway but can proceed along different avenues.
Collapse
Affiliation(s)
- Elnaz Aliyari
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
14
|
Loo SL, Vásquez L, Zahid M, Costantino F, Athanassiou A, Fragouli D. 3D Photothermal Cryogels for Solar-Driven Desalination. ACS APPLIED MATERIALS & INTERFACES 2021; 13:30542-30555. [PMID: 34156821 PMCID: PMC8289246 DOI: 10.1021/acsami.1c05087] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 06/09/2021] [Indexed: 05/27/2023]
Abstract
This paper reports the fabrication of photothermal cryogels for freshwater production via the solar-driven evaporation of seawater. Photothermal cryogels were prepared via in situ oxidative polymerization of pyrrole with ammonium persulfate on preformed poly(sodium acrylate) (PSA) cryogels. We found that the pyrrole concentration used in the fabrication process has a significant effect on the final PSA/PPy cryogels (PPCs), causing the as-formed polypyrrole (PPy) layer on the PPC to evolve from nanoparticles to lamellar sheets and to consolidated thin films. PPC fabricated using the lowest pyrrole concentration (i.e., PPC10) displays the best solar-evaporation efficiency compared to the other samples, which is further improved by switching the operative mode from floating to standing. Specifically, in the latter case, the apparent solar evaporation rate and solar-to-vapor conversion efficiency reach 1.41 kg m-2 h-1 and 96.9%, respectively, due to the contribution of evaporation from the exposed lateral surfaces. The distillate obtained from the condensed vapor, generated via solar evaporation of a synthetic seawater through PPC10, shows an at least 99.99% reduction of Na while all the other elements are reduced to a subppm level. We attribute the superior solar evaporation and desalination performance of PPC10 to its (i) higher photoabsorption efficiency, (ii) higher heat localization effect, (iii) open porous structure that facilitates vapor removal, (iv) rough pore surface that increases the surface area for light absorption and water evaporation, and (v) higher water-absorption capacity to ensure efficient water replenishment to the evaporative sites. It is anticipated that the gained know-how from this study would offer insightful guidelines to better designs of polymer-based 3D photothermal materials for solar evaporation as well as for other emerging solar-related applications.
Collapse
Affiliation(s)
- Siew-Leng Loo
- Smart
Materials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Lía Vásquez
- Smart
Materials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- Dipartimento
di Chimica e Chimica Industriale (DCCI) Università degli Studi di Genova, Via Dodecaneso 31, 16146 Genova, Italy
| | - Muhammad Zahid
- Smart
Materials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | - Federica Costantino
- Smart
Materials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
- Interdisciplinary
Laboratories for Advanced Materials Physics (i-LAMP) and Dipartimento
di Matematica e Fisica, Università
Cattolica del Sacro Cuore, Via Musei 41, 25121 Brescia, Italy
| | | | - Despina Fragouli
- Smart
Materials, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| |
Collapse
|
15
|
Spoel D, Zhang J, Zhang H. Quantitative predictions from molecular simulations using explicit or implicit interactions. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2021. [DOI: 10.1002/wcms.1560] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- David Spoel
- Uppsala Center for Computational Chemistry, Science for Life Laboratory, Department of Cell and Molecular Biology Uppsala University Uppsala Sweden
| | - Jin Zhang
- Department of Chemistry Southern University of Science and Technology Shenzhen China
| | - Haiyang Zhang
- Department of Biological Science and Engineering, School of Chemistry and Biological Engineering University of Science and Technology Beijing Beijing China
| |
Collapse
|
16
|
Pelimanni E, Hautala L, Hans A, Kivimäki A, Kook M, Küstner-Wetekam C, Marder L, Patanen M, Huttula M. Core and Valence Level Photoelectron Spectroscopy of Nanosolvated KCl. J Phys Chem A 2021; 125:4750-4759. [PMID: 34034483 PMCID: PMC8279652 DOI: 10.1021/acs.jpca.1c01539] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/22/2021] [Indexed: 01/04/2023]
Abstract
The solvation of alkali and halide ions in the aqueous environment has been a subject of intense experimental and theoretical research with multidisciplinary interests; yet, a comprehensive molecular-level understanding has still not been obtained. In recent years, electron spectroscopy has been increasingly applied to study the electronic and structural properties of aqueous ions with implications, especially in atmospheric chemistry. In this work, we report core and valence level (Cl 2p, Cl 3p, and K 3p) photoelectron spectra of the common alkali halide, KCl, doped in gas-phase water clusters in the size range of a few hundred water molecules. The results indicate that the electronic structure of these nanosolutions shows a distinct character from that observed at the liquid-vapor interface in liquid microjets and ambient pressure setups. Insights are provided into the unique solvation properties of ions in a nanoaqueous environment, emerging properties of bulk electrolyte solutions with growing cluster size, and sensitivity of the electronic structure to varying solvation configurations.
Collapse
Affiliation(s)
- Eetu Pelimanni
- Nano
and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Lauri Hautala
- Nano
and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Andreas Hans
- Nano
and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
- Universität
Kassel, Institut für Physik und CINSaT, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Antti Kivimäki
- Nano
and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
- MAX
IV Laboratory, Lund University, P.O. Box 118, SE-22100 Lund, Sweden
| | - Mati Kook
- Institute
of Physics, University of Tartu, W. Ostwaldi 1, EE-50411 Tartu, Estonia
| | - Catmarna Küstner-Wetekam
- Universität
Kassel, Institut für Physik und CINSaT, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Lutz Marder
- Universität
Kassel, Institut für Physik und CINSaT, Heinrich-Plett-Straße 40, 34132 Kassel, Germany
| | - Minna Patanen
- Nano
and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Marko Huttula
- Nano
and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| |
Collapse
|
17
|
Huang Q, Wei H, Marr LC, Vikesland PJ. Direct Quantification of the Effect of Ammonium on Aerosol Droplet pH. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:778-787. [PMID: 33296596 DOI: 10.1021/acs.est.0c07394] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ammonium is an important atmospheric constituent that dictates many environmental processes. The impact of the ammonium ion concentration on 10-50 μm aerosol droplet pH was quantified using pH nanoprobes and surface-enhanced Raman spectroscopy (SERS). Sample solutions were prepared by mixing 1 M ammonium sulfate (AS), ammonium nitrate (AN), sodium sulfate (SS), or sodium nitrate (SN) solutions with 1 M phosphate buffer (PB) at different volume ratios. Stable pH values were measured for pure PB, AS, and AN droplets at different concentrations. The centroid pH of 1 M PB droplets was ∼11, but when PB was systematically replaced with ammonium (AS- or AN-PB), the centroid pH within the droplets decreased from ≈11 to 5.5. Such a decrease was not observed in sodium (SS- or SN-PB) droplets, and no pH differences were observed between sulfate and nitrate salts. Ammonia partitioning to the gas phase in ammonium-containing droplets was evaluated to be negligible. Raman sulfate peak (∼980 cm-1) intensity measurements and surface tension measurements were conducted to investigate changes in ion distribution. The pH difference between ammonium-containing droplets and ammonium-free droplets is attributed to the alteration of the ion distribution in the presence of ammonium.
Collapse
Affiliation(s)
- Qishen Huang
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
- Virginia Tech Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology Center, Blacksburg, Virginia 24061, United States
| | - Haoran Wei
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
- Virginia Tech Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology Center, Blacksburg, Virginia 24061, United States
| | - Peter J Vikesland
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
- Virginia Tech Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology Center, Blacksburg, Virginia 24061, United States
| |
Collapse
|
18
|
|
19
|
Abaye DA, Agbo IA, Nielsen BV. Current perspectives on supercharging reagents in electrospray ionization mass spectrometry. RSC Adv 2021; 11:20355-20369. [PMID: 35479879 PMCID: PMC9033978 DOI: 10.1039/d1ra00745a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/02/2021] [Indexed: 11/21/2022] Open
Abstract
In electrospray ionization mass spectrometry (ESI-MS), analytes are introduced into the mass spectrometer in typically aqueous-organic solvent mixtures, including pH modifiers. One mechanism for improving the signal intensity and simultaneously increasing the generation of higher charge-state ions is the inclusion of small amounts (approx. <0.5% v/v mobile phase solution) of charge-inducing or supercharging reagents, such as m-nitrobenzyl alcohol, o-nitrobenzyl alcohol, m-nitrobenzonitrile, m-(trifluoromethyl)-benzyl alcohol and sulfolane. We explore the direct and indirect (colligative properties) that have been proposed as responsible for their modes of action during ESI. Of the many theorized mechanisms of ESI, we re-visit the three most popular and highlight how they are impacted by supercharging observations on small ions to large molecules including proteins. We then provide a comprehensive list of 34 supercharging reagents that have been demonstrated in ESI experiments. We include an additional 19 potential candidate isomers as supercharging reagents and comment on their broad physico-chemical properties. It is becoming increasingly obvious that advances in technology and improved ion source design, analyzers e.g. the use of ion mobility, ion trap, circular dichroism (CD) spectroscopy, together with computer modeling are increasing the knowledge base and, together with the untested isomers and yet-to-be unearthed ones, offer opportunities for further research and application in other areas of polymer research. A simple illustration of the positive electrospray ionization (ESI) environment.![]()
Collapse
Affiliation(s)
- Daniel A. Abaye
- Department of Basic Sciences
- School of Basic and Biomedical Sciences
- University of Health and Allied Sciences
- Ho
- Ghana
| | - Irene A. Agbo
- Department of Basic Sciences
- School of Basic and Biomedical Sciences
- University of Health and Allied Sciences
- Ho
- Ghana
| | - Birthe V. Nielsen
- School of Science
- Faculty of Engineering and Science
- University of Greenwich
- Kent
- UK
| |
Collapse
|
20
|
Zhang M, Han F, Li C, Wang P, Yang Y, Yu K. Combined effect of weak electric field and ions on critical water cluster: Insight from molecular dynamics simulation. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2020.110932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
21
|
Duez Q, Metwally H, Hoyas S, Lemaur V, Cornil J, De Winter J, Konermann L, Gerbaux P. Effects of electrospray mechanisms and structural relaxation on polylactide ion conformations in the gas phase: insights from ion mobility spectrometry and molecular dynamics simulations. Phys Chem Chem Phys 2020; 22:4193-4204. [DOI: 10.1039/c9cp06391a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Gas-phase polymer ions may retain structural features associated with their electrospray formation mechanisms.
Collapse
Affiliation(s)
- Quentin Duez
- Organic Synthesis and Mass Spectrometry Laboratory
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
- Laboratory for Chemistry of Novel Materials
| | - Haidy Metwally
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Sébastien Hoyas
- Organic Synthesis and Mass Spectrometry Laboratory
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
- Laboratory for Chemistry of Novel Materials
| | - Vincent Lemaur
- Laboratory for Chemistry of Novel Materials
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
| | - Jérôme Cornil
- Laboratory for Chemistry of Novel Materials
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
| | - Julien De Winter
- Organic Synthesis and Mass Spectrometry Laboratory
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
| | - Lars Konermann
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Pascal Gerbaux
- Organic Synthesis and Mass Spectrometry Laboratory
- Center of Innovation and Research in Materials and Polymers (CIRMAP) – University of Mons (UMONS)
- B-7000 Mons
- Belgium
| |
Collapse
|
22
|
Peters I, Metwally H, Konermann L. Mechanism of Electrospray Supercharging for Unfolded Proteins: Solvent-Mediated Stabilization of Protonated Sites During Chain Ejection. Anal Chem 2019; 91:6943-6952. [DOI: 10.1021/acs.analchem.9b01470] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Insa Peters
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Haidy Metwally
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
23
|
Konermann L, Metwally H, Duez Q, Peters I. Charging and supercharging of proteins for mass spectrometry: recent insights into the mechanisms of electrospray ionization. Analyst 2019; 144:6157-6171. [DOI: 10.1039/c9an01201j] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Molecular dynamics simulations have uncovered mechanistic details of the protein ESI process under various experimental conditions.
Collapse
Affiliation(s)
- Lars Konermann
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Haidy Metwally
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Quentin Duez
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| | - Insa Peters
- Department of Chemistry
- The University of Western Ontario
- London
- Canada
| |
Collapse
|
24
|
Kondalaji SG, Khakinejad M, Valentine SJ. Comprehensive Peptide Ion Structure Studies Using Ion Mobility Techniques: Part 3. Relating Solution-Phase to Gas-Phase Structures. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:1665-1677. [PMID: 29858839 PMCID: PMC6525623 DOI: 10.1007/s13361-018-1996-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/02/2018] [Accepted: 05/02/2018] [Indexed: 05/16/2023]
Abstract
Molecular dynamics (MD) simulations have been utilized to study peptide ion conformer establishment during the electrospray process. An explicit water model is used for nanodroplets containing a model peptide and hydronium ions. Simulations are conducted at 300 K for two different peptide ion charge configurations and for droplets containing varying numbers of hydronium ions. For all conditions, modeling has been performed until production of the gas-phase ions and the resultant conformers have been compared to proposed gas-phase structures. The latter species were obtained from previous studies in which in silico candidate structures were filtered according to ion mobility and hydrogen-deuterium exchange (HDX) reactivity matches. Results from the present study present three key findings namely (1) the evidence from ion production modeling supports previous structure refinement studies based on mobility and HDX reactivity matching, (2) the modeling of the electrospray process is significantly improved by utilizing initial droplets existing below but close to the calculated Rayleigh limit, and (3) peptide ions in the nanodroplets sample significantly different conformers than those in the bulk solution due to altered physicochemical properties of the solvent. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Samaneh Ghassabi Kondalaji
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Mahdiar Khakinejad
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Stephen J Valentine
- Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
| |
Collapse
|
25
|
Longhi G, Ceselli A, Fornili SL, Turco Liveri V. Molecular dynamics and metadynamics simulations of electrosprayed water nanodroplets including sodium bis(2-ethylhexyl)sulfosuccinate micelles. J Chem Phys 2018; 146:204305. [PMID: 28571388 DOI: 10.1063/1.4984038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The behavior of aqueous solutions of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) under conditions of electrospray ionization (ESI) has been investigated by molecular dynamics (MD) and well-tempered metadynamics (WTM) simulations at 300 K and 400 K. We have examined water droplets with initial fixed numbers of water molecules (1000) and AOT- anions (100), and with sodium cations in the range of 70-130. At 300 K, all charged droplets show the water evaporation rate increasing with the absolute value of the initial droplet charge state (Z), accompanied by ejection of an increasing number of solvated sodium ions or by expulsion of AOT- anions depending on the sign of Z and by fragmentation in the case of high |Z|. At 400 K, the water evaporation becomes more rapid and the fission process more extensive. In all cases, the AOTNa molecules, arranged as a direct micelle inside the aqueous system, undergo a rapid inversion in vacuo so that the hydrophilic heads and sodium ions surrounded by water molecules move toward the droplet interior. At the end of the 100-ns MD simulations, some water molecules remain within the aggregates at both temperatures. The subsequent metadynamics simulations accelerate the droplet evolution and show that all systems become anhydrous, in agreement with the experimental results of ESI mass spectrometry. This complete water loss is accompanied by sodium counterion emission for positively charged aggregates at 300 K. The analysis shows how the temperature and droplet charge state affect the populations of the generated surfactant aggregates, providing information potentially useful in designing future ESI experimental conditions.
Collapse
Affiliation(s)
- Giovanna Longhi
- Dipartimento di Medicina Molecolare e Traslazionale, Università di Brescia, Viale Europa 11, 25123 Brescia, Italy
| | - Alberto Ceselli
- Dipartimento di Informatica, Università di Milano, Via Bramante 65, 26013 Crema, Cremona, Italy
| | - Sandro L Fornili
- Dipartimento di Informatica, Università di Milano, Via Bramante 65, 26013 Crema, Cremona, Italy
| | - Vincenzo Turco Liveri
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche "STEBICEF," Università degli Studi di Palermo, Viale delle Scienze I, 90128 Palermo, Italy
| |
Collapse
|
26
|
Zhu Z, Sheng N, Fang H, Wan R. Colored spectrum characteristics of thermal noise on the molecular scale. Phys Chem Chem Phys 2016; 18:30189-30195. [PMID: 27779258 DOI: 10.1039/c6cp04433f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Thermal noise is of fundamental importance to many processes. Traditionally, thermal noise has been treated as white noise on the macroscopic scale. Using molecular dynamics simulations and power spectrum analysis, we show that the thermal noise of solute molecules in water is non-white on the molecular scale, which is in contrast to the conventional theory. In the frequency domain from 2 × 1011 Hz to 1013 Hz, the power spectrum of thermal noise for polar solute molecules resembles the spectrum of 1/f noise. The power spectrum of thermal noise for non-polar solute molecules deviates only slightly from the spectrum of white noise. The key to this phenomenon is the existence of hydrogen bonds between polar solute molecules and solvent water molecules. Furthermore, for polar solute molecules, the degree of power spectrum deviation from that of white noise is associated with the average lifetime of the hydrogen bonds between the solute and the solvent molecules.
Collapse
Affiliation(s)
- Zhi Zhu
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800, China. and University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nan Sheng
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800, China.
| | - Haiping Fang
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800, China.
| | - Rongzheng Wan
- Division of Interfacial Water and Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P.O. Box 800-204, Shanghai 201800, China.
| |
Collapse
|
27
|
Bellissent-Funel MC, Hassanali A, Havenith M, Henchman R, Pohl P, Sterpone F, van der Spoel D, Xu Y, Garcia AE. Water Determines the Structure and Dynamics of Proteins. Chem Rev 2016; 116:7673-97. [PMID: 27186992 DOI: 10.1021/acs.chemrev.5b00664] [Citation(s) in RCA: 540] [Impact Index Per Article: 67.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Water is an essential participant in the stability, structure, dynamics, and function of proteins and other biomolecules. Thermodynamically, changes in the aqueous environment affect the stability of biomolecules. Structurally, water participates chemically in the catalytic function of proteins and nucleic acids and physically in the collapse of the protein chain during folding through hydrophobic collapse and mediates binding through the hydrogen bond in complex formation. Water is a partner that slaves the dynamics of proteins, and water interaction with proteins affect their dynamics. Here we provide a review of the experimental and computational advances over the past decade in understanding the role of water in the dynamics, structure, and function of proteins. We focus on the combination of X-ray and neutron crystallography, NMR, terahertz spectroscopy, mass spectroscopy, thermodynamics, and computer simulations to reveal how water assist proteins in their function. The recent advances in computer simulations and the enhanced sensitivity of experimental tools promise major advances in the understanding of protein dynamics, and water surely will be a protagonist.
Collapse
Affiliation(s)
| | - Ali Hassanali
- International Center for Theoretical Physics, Condensed Matter and Statistical Physics 34151 Trieste, Italy
| | - Martina Havenith
- Ruhr-Universität Bochum , Faculty of Chemistry and Biochemistry Universitätsstraße 150 Building NC 7/72, D-44780 Bochum, Germany
| | - Richard Henchman
- Manchester Institute of Biotechnology The University of Manchester , 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Peter Pohl
- Johannes Kepler University , Gruberstrasse, 40 4020 Linz, Austria
| | - Fabio Sterpone
- Institut de Biologie Physico-Chimique Laboratoire de Biochimie Théorique 13 Rue Pierre et Marie Curie, 75005 Paris, France
| | - David van der Spoel
- Department of Cell and Molecular Biology, Computational and Systems Biology, Uppsala University , 751 24 Uppsala, Sweden
| | - Yao Xu
- Ruhr-Universität Bochum , Faculty of Chemistry and Biochemistry Universitätsstraße 150 Building NC 7/72, D-44780 Bochum, Germany
| | - Angel E Garcia
- Center for Non Linear Studies, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| |
Collapse
|
28
|
Metwally H, McAllister RG, Popa V, Konermann L. Mechanism of Protein Supercharging by Sulfolane and m-Nitrobenzyl Alcohol: Molecular Dynamics Simulations of the Electrospray Process. Anal Chem 2016; 88:5345-54. [DOI: 10.1021/acs.analchem.6b00650] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Haidy Metwally
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Robert G. McAllister
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Vlad Popa
- Department
of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Lars Konermann
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
- Department
of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| |
Collapse
|
29
|
Zhang C, Wang Y, Liu Y, Yang Y. A molecular dynamics study of water vapor nucleation in the presence of ions. Chem Eng Sci 2015. [DOI: 10.1016/j.ces.2015.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
30
|
Zhang J, Borg MK, Sefiane K, Reese JM. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:052403. [PMID: 26651708 DOI: 10.1103/physreve.92.052403] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Indexed: 06/05/2023]
Abstract
We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.
Collapse
Affiliation(s)
- Jun Zhang
- James Weir Fluids Laboratory, Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow G1 1XJ, United Kingdom
| | - Matthew K Borg
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, United Kingdom
| | - Khellil Sefiane
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, United Kingdom
- Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China
| | - Jason M Reese
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, United Kingdom
| |
Collapse
|
31
|
McAllister RG, Metwally H, Sun Y, Konermann L. Release of Native-like Gaseous Proteins from Electrospray Droplets via the Charged Residue Mechanism: Insights from Molecular Dynamics Simulations. J Am Chem Soc 2015; 137:12667-76. [DOI: 10.1021/jacs.5b07913] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Robert G. McAllister
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Haidy Metwally
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Yu Sun
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
32
|
Metwally H, McAllister RG, Konermann L. Exploring the Mechanism of Salt-Induced Signal Suppression in Protein Electrospray Mass Spectrometry Using Experiments and Molecular Dynamics Simulations. Anal Chem 2015; 87:2434-42. [DOI: 10.1021/ac5044016] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Haidy Metwally
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Robert G. McAllister
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
33
|
Konermann L, McAllister RG, Metwally H. Molecular Dynamics Simulations of the Electrospray Process: Formation of NaCl Clusters via the Charged Residue Mechanism. J Phys Chem B 2014; 118:12025-33. [DOI: 10.1021/jp507635y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Robert G. McAllister
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Haidy Metwally
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
34
|
Kim E, Yeom MS. Structural Arrangement of Water Molecules around Highly Charged Nanoparticles: Molecular Dynamics Simulation. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.5.1501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
35
|
Hub JS, Wolf MG, Caleman C, van Maaren PJ, Groenhof G, van der Spoel D. Thermodynamics of hydronium and hydroxide surface solvation. Chem Sci 2014. [DOI: 10.1039/c3sc52862f] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
36
|
Musolino N, Trout BL. Insight into the molecular mechanism of water evaporation via the finite temperature string method. J Chem Phys 2013; 138:134707. [PMID: 23574252 DOI: 10.1063/1.4798458] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The process of water's evaporation at its liquid/air interface has proven challenging to study experimentally and, because it constitutes a rare event on molecular time scales, presents a challenge for computer simulations as well. In this work, we simulated water's evaporation using the classical extended simple point charge model water model, and identified a minimum free energy path for this process in terms of 10 descriptive order parameters. The measured free energy change was 7.4 kcal/mol at 298 K, in reasonable agreement with the experimental value of 6.3 kcal/mol, and the mean first-passage time was 1375 ns for a single molecule, corresponding to an evaporation coefficient of 0.25. In the observed minimum free energy process, the water molecule diffuses to the surface, and tends to rotate so that its dipole and one O-H bond are oriented outward as it crosses the Gibbs dividing surface. As the water molecule moves further outward through the interfacial region, its local density is higher than the time-averaged density, indicating a local solvation shell that protrudes from the interface. The water molecule loses donor and acceptor hydrogen bonds, and then, with its dipole nearly normal to the interface, stops donating its remaining hydrogen bond. At that point, when the final, accepted hydrogen bond is broken, the water molecule is free. We also analyzed which order parameters are most important in the process and in reactive trajectories, and found that the relative orientation of water molecules near the evaporating molecule, and the number of accepted hydrogen bonds, were important variables in reactive trajectories and in kinetic descriptions of the process.
Collapse
Affiliation(s)
- Nicholas Musolino
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Rm. E19-502, Cambridge, Massachusetts 02144, USA
| | | |
Collapse
|
37
|
Molecular Dynamics Simulations on Evaporation of Droplets with Dissolved Salts. ENTROPY 2013. [DOI: 10.3390/e15041232] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
38
|
Daub CD, Cann NM. Molecular Dynamics Simulations to Examine Structure, Energetics, and Evaporation/Condensation Dynamics in Small Charged Clusters of Water or Methanol Containing a Single Monatomic Ion. J Phys Chem A 2012; 116:10488-95. [DOI: 10.1021/jp308217q] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Christopher D. Daub
- Department of Chemistry, Queen’s University, 90 Bader
Lane, Kingston,
Ontario, Canada K7L3N6
| | - Natalie M. Cann
- Department of Chemistry, Queen’s University, 90 Bader
Lane, Kingston,
Ontario, Canada K7L3N6
| |
Collapse
|
39
|
|
40
|
Caleman C, van Maaren PJ, Hong M, Hub JS, Costa LT, van der Spoel D. Force Field Benchmark of Organic Liquids: Density, Enthalpy of Vaporization, Heat Capacities, Surface Tension, Isothermal Compressibility, Volumetric Expansion Coefficient, and Dielectric Constant. J Chem Theory Comput 2012; 8:61-74. [PMID: 22241968 PMCID: PMC3254193 DOI: 10.1021/ct200731v] [Citation(s) in RCA: 463] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Indexed: 12/15/2022]
Abstract
The chemical composition of small organic molecules is often very similar to amino acid side chains or the bases in nucleic acids, and hence there is no a priori reason why a molecular mechanics force field could not describe both organic liquids and biomolecules with a single parameter set. Here, we devise a benchmark for force fields in order to test the ability of existing force fields to reproduce some key properties of organic liquids, namely, the density, enthalpy of vaporization, the surface tension, the heat capacity at constant volume and pressure, the isothermal compressibility, the volumetric expansion coefficient, and the static dielectric constant. Well over 1200 experimental measurements were used for comparison to the simulations of 146 organic liquids. Novel polynomial interpolations of the dielectric constant (32 molecules), heat capacity at constant pressure (three molecules), and the isothermal compressibility (53 molecules) as a function of the temperature have been made, based on experimental data, in order to be able to compare simulation results to them. To compute the heat capacities, we applied the two phase thermodynamics method (Lin et al. J. Chem. Phys.2003, 119, 11792), which allows one to compute thermodynamic properties on the basis of the density of states as derived from the velocity autocorrelation function. The method is implemented in a new utility within the GROMACS molecular simulation package, named g_dos, and a detailed exposé of the underlying equations is presented. The purpose of this work is to establish the state of the art of two popular force fields, OPLS/AA (all-atom optimized potential for liquid simulation) and GAFF (generalized Amber force field), to find common bottlenecks, i.e., particularly difficult molecules, and to serve as a reference point for future force field development. To make for a fair playing field, all molecules were evaluated with the same parameter settings, such as thermostats and barostats, treatment of electrostatic interactions, and system size (1000 molecules). The densities and enthalpy of vaporization from an independent data set based on simulations using the CHARMM General Force Field (CGenFF) presented by Vanommeslaeghe et al. (J. Comput. Chem.2010, 31, 671) are included for comparison. We find that, overall, the OPLS/AA force field performs somewhat better than GAFF, but there are significant issues with reproduction of the surface tension and dielectric constants for both force fields.
Collapse
Affiliation(s)
- Carl Caleman
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron Notkestraße 85, DE-22607 Hamburg, Germany
| | - Paul J. van Maaren
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-75124 Uppsala, Sweden
| | - Minyan Hong
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-75124 Uppsala, Sweden
| | - Jochen S. Hub
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-75124 Uppsala, Sweden
| | - Luciano T. Costa
- Departamento de Ciências Exatas, Federal University of Alfenas—MG Rua Gabriel Monteiro da Silva, 700 Alfenas—MG CEP:37130-000, Brazil
| | - David van der Spoel
- Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-75124 Uppsala, Sweden
| |
Collapse
|
41
|
Hub JS, Caleman C, van der Spoel D. Organic molecules on the surface of water droplets – an energetic perspective. Phys Chem Chem Phys 2012; 14:9537-45. [DOI: 10.1039/c2cp40483d] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
|
42
|
Ahadi E, Konermann L. Modeling the Behavior of Coarse-Grained Polymer Chains in Charged Water Droplets: Implications for the Mechanism of Electrospray Ionization. J Phys Chem B 2011; 116:104-12. [DOI: 10.1021/jp209344z] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Elias Ahadi
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
43
|
Daub CD, Cann NM. How Are Completely Desolvated Ions Produced in Electrospray Ionization: Insights from Molecular Dynamics Simulations. Anal Chem 2011; 83:8372-6. [DOI: 10.1021/ac202103p] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Christopher D. Daub
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
| | - Natalie M. Cann
- Department of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
| |
Collapse
|
44
|
Ahadi E, Konermann L. Ejection of Solvated Ions from Electrosprayed Methanol/Water Nanodroplets Studied by Molecular Dynamics Simulations. J Am Chem Soc 2011; 133:9354-63. [DOI: 10.1021/ja111492s] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elias Ahadi
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
45
|
Caleman C, Hub JS, van Maaren PJ, van der Spoel D. Atomistic simulation of ion solvation in water explains surface preference of halides. Proc Natl Acad Sci U S A 2011; 108:6838-6842. [PMCID: PMC3084043 DOI: 10.1073/pnas.1017903108] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024] Open
Abstract
Water is a demanding partner. It strongly attracts ions, yet some halide anions—chloride, bromide, and iodide—are expelled to the air/water interface. This has important implications for chemistry in the atmosphere, including the ozone cycle. We present a quantitative analysis of the energetics of ion solvation based on molecular simulations of all stable alkali and halide ions in water droplets. The potentials of mean force for Cl-, Br-, and I- have shallow minima near the surface. We demonstrate that these minima derive from more favorable water–water interaction energy when the ions are partially desolvated. Alkali cations are on the inside because of the favorable ion–water energy, whereas F- is driven inside by entropy. Models attempting to explain the surface preference based on one or more ion properties such as polarizability or size are shown to lead to qualitative and quantitative errors, prompting a paradigm shift in chemistry away from such simplifications.
Collapse
Affiliation(s)
- Carl Caleman
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron, Notkestraße 85, DE-22607 Hamburg, Germany; and
| | - Jochen S. Hub
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, SE-75 124 Uppsala, Sweden
| | - Paul J. van Maaren
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, SE-75 124 Uppsala, Sweden
| | - David van der Spoel
- Department of Cell and Molecular Biology, Biomedical Center, Box 596, Uppsala University, SE-75 124 Uppsala, Sweden
| |
Collapse
|
46
|
Mason PE. Molecular Dynamics Study on the Microscopic Details of the Evaporation of Water. J Phys Chem A 2011; 115:6054-8. [DOI: 10.1021/jp1104517] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Phillip E. Mason
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, New York 14853, United States
| |
Collapse
|
47
|
van der Spoel D, Marklund EG, Larsson DSD, Caleman C. Proteins, Lipids, and Water in the Gas Phase. Macromol Biosci 2010; 11:50-9. [DOI: 10.1002/mabi.201000291] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
48
|
Ahadi E, Konermann L. Surface Charge of Electrosprayed Water Nanodroplets: A Molecular Dynamics Study. J Am Chem Soc 2010; 132:11270-7. [DOI: 10.1021/ja1041989] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Elias Ahadi
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| |
Collapse
|
49
|
Calvo F, Douady J. Stepwise hydration and evaporation of adenosine monophosphate nucleotide anions: a multiscale theoretical study. Phys Chem Chem Phys 2010; 12:3404-14. [PMID: 20336245 DOI: 10.1039/b923972c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The structure and finite-temperature properties of hydrated nucleotide anion adenosine 5'-monophosphate (AMP) have been theoretically investigated with a variety of methods. Using a polarizable version of the Amber force field and replica-exchange molecular dynamics simulations, putative lowest-energy structures have been located for the AMP(-)(H(2)O)(n) cluster anions with n = 0-20. The hydration energies obtained with the molecular mechanics potential slightly overestimate experimental measurements. However, closer values are found after reoptimizing the structures locally at more sophisticated levels, namely semi-empirical (PM6) and density-functional theory (B3LYP/6-31+G*). Upon heating the complexes, various indicators such as the heat capacity, number of hydrogen bonds or surface area provide evidence that the water cluster melts below 200 K but remains bonded to the AMP anion. The sequential loss of water molecules after sudden heating has been studied using a statistical approach in which unimolecular evaporation is described using the orbiting transition state version of phase space theory, together with anharmonic densities of vibrational states. The evaporation rates are calibrated based on the results of molecular dynamics trajectories at high internal energy. Our results indicate that between 4 and 10 water molecules are lost from AMP(-)(H(2)O)(20) after one second depending on the initial heating in the 250-350 K range, with a concomitant cooling of the remaining cluster by 75-150 K.
Collapse
Affiliation(s)
- F Calvo
- LASIM, Université de Lyon and CNRS UMR 5579, Bât. A. Kastler, 43 Bd du 11 novembre 1918, F69622 Villeurbanne Cedex, France.
| | | |
Collapse
|
50
|
Calvo F, Douady J, Spiegelman F. Accurate evaporation rates of pure and doped water clusters in vacuum: A statistico-dynamical approach. J Chem Phys 2010; 132:024305. [DOI: 10.1063/1.3280168] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|