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Development of a Mobile Analytical Chemistry Workstation Using a Silicon Electrochromatography Microchip and Capacitively Coupled Contactless Conductivity Detector. MICROMACHINES 2021; 12:mi12030239. [PMID: 33673410 PMCID: PMC7996726 DOI: 10.3390/mi12030239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/08/2021] [Accepted: 02/20/2021] [Indexed: 11/16/2022]
Abstract
Capillary electrochromatography (CEC) is a separation technique that hybridizes liquid chromatography (LC) and capillary electrophoresis (CE). The selectivity offered by LC stationary phase results in rapid separations, high efficiency, high selectivity, minimal analyte and buffer consumption. Chip-based CE and CEC separation techniques are also gaining interest, as the microchip can provide precise on-chip control over the experiment. Capacitively coupled contactless conductivity detection (C4D) offers the contactless electrode configuration, and thus is not in contact with the solutions under investigation. This prevents contamination, so it can be easy to use as well as maintain. This study investigated a chip-based CE/CEC with C4D technique, including silicon-based microfluidic device fabrication processes with packaging, design and optimization. It also examined the compatibility of the silicon-based CEC microchip interfaced with C4D. In this paper, the authors demonstrated a nanofabrication technique for a novel microchip electrochromatography (MEC) device, whose capability is to be used as a mobile analytical equipment. This research investigated using samples of potassium ions, sodium ions and aspirin (acetylsalicylic acid).
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Schure MR, Maier RS. Ellipsoidal particles for liquid chromatography: Fluid mechanics, efficiency and wall effects. J Chromatogr A 2018; 1580:30-48. [DOI: 10.1016/j.chroma.2018.09.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/16/2018] [Accepted: 09/24/2018] [Indexed: 10/28/2022]
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Affiliation(s)
- Xilong Yuan
- Department of Chemistry, Queen's University , Kingston, Ontario K7L 3N6, Canada
| | - Richard D Oleschuk
- Department of Chemistry, Queen's University , Kingston, Ontario K7L 3N6, Canada
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Strickhouser RB, Hatab NA, Lavrik NV, Sepaniak MJ. Centrifugal-driven, reduced-dimension, planar chromatography. Electrophoresis 2017; 39:438-444. [PMID: 28504823 DOI: 10.1002/elps.201700148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 04/28/2017] [Accepted: 05/03/2017] [Indexed: 11/12/2022]
Abstract
A fundamental problem with efficiency in capillary action driven planar chromatography results from diminishing flow rates as development proceeds, giving rise to molecular diffusion related band dispersion for most sample types. Overpressure and electrokinetic means to speed flow have been used successfully in TLC. We explore the use of centrifugal force (CF) to drive flow for reduced-dimension planar platforms (ultra-TLC, low micrometer features, and nano-TLC, nanoscale features). The silicon wafer platforms have two forms of continuous 2D arrays created by either photolithography or metal dewetting followed by deep reactive ion etching and coated with porous SiO2 . The flow pattern is unusual with co-planar flows above and within the arrays. The effects of parameters such as spin rate, solvent type, and surface character on flow rates is established and can be substantially greater than capillary action flow. Using fluorescent dyes, we investigate retardation factors and chromatographic plate height; the latter falls in the low to sub-micrometer range. To the best of our knowledge, we demonstrate the first analytical separations performed in pillar arrays using CF to augment solvent flow.
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Affiliation(s)
| | - Nahla A Hatab
- Department of Chemistry, University of Tennessee, Knoxville, TN, USA
| | - Nickolay V Lavrik
- Center of Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA
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Wallace RA, Lavrik NV, Sepaniak MJ. Ultra‐thin layer chromatography with integrated silver colloid‐based SERS detection. Electrophoresis 2016; 38:361-367. [DOI: 10.1002/elps.201600319] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/03/2016] [Accepted: 08/03/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Ryan A. Wallace
- Department of Chemistry University of Tennessee Knoxville TN USA
| | - Nickolay V. Lavrik
- Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN USA
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Lincoln DR, Lavrik NV, Kravchenko II, Sepaniak MJ. Retention in Porous Layer Pillar Array Planar Separation Platforms. Anal Chem 2016; 88:8741-8. [PMID: 27510171 DOI: 10.1021/acs.analchem.6b02079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This work presents the retention capabilities and surface area enhancement of highly ordered, high-aspect-ratio, open-platform, two-dimensional (2D) pillar arrays when coated with a thin layer of porous silicon oxide (PSO). Photolithographically prepared pillar arrays were coated with 50-250 nm of PSO via plasma-enhanced chemical vapor deposition and then functionalized with either octadecyltrichlorosilane or n-butyldimethylchlorosilane. Theoretical calculations indicate that a 50 nm layer of PSO increases the surface area of a pillar nearly 120-fold. Retention capabilities were tested by observing capillary-action-driven development under various conditions, as well as by running one-dimensional separations on varying thicknesses of PSO. Increasing the thickness of PSO on an array clearly resulted in greater retention of the analyte(s) in question in both experiments. In culmination, a two-dimensional separation of fluorescently derivatized amines was performed to further demonstrate the capabilities of these fabricated platforms.
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Affiliation(s)
- Danielle R Lincoln
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
| | - Nickolay V Lavrik
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States
| | - Ivan I Kravchenko
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States
| | - Michael J Sepaniak
- Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States
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Abstract
This review focuses on recent advances in the field of microfluidic liquid chromatography from January 2013 through April 2015. Articles are organized by the type of stationary phase support focusing on device fabrication, column preparation, and use for specific applications. Additionally, a comprehensive table comparing chromatographic figures of merit for the work described is included as Appendix A as a reference for readers.
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Affiliation(s)
- James P. Grinias
- Department of Chemistry, University of Michigan, Ann Arbor,
MI 48109, USA
| | - Robert T. Kennedy
- Department of Chemistry, University of Michigan, Ann Arbor,
MI 48109, USA
- Department of Pharmacology, University of Michigan, Ann
Arbor, MI 48109, USA
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Crane NA, Lavrik NV, Sepaniak MJ. Manipulating the inter pillar gap in pillar array ultra-thin layer planar chromatography platforms. Analyst 2016; 141:1239-45. [DOI: 10.1039/c5an02274f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An advantage of separation platforms based on deterministic micro- and nano-fabrications, relative to traditional systems based on packed beds of particles, is the exquisite control of all morphological parameters.
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Affiliation(s)
| | - Nickolay V. Lavrik
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
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Müllner T, Unger KK, Tallarek U. Characterization of microscopic disorder in reconstructed porous materials and assessment of mass transport-relevant structural descriptors. NEW J CHEM 2016. [DOI: 10.1039/c5nj03346b] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Charlton JJ, Jones NC, Wallace RA, Smithwick RW, Bradshaw JA, Kravchenko II, Lavrik NV, Sepaniak MJ. Nanopillar Based Enhanced-Fluorescence Detection of Surface-Immobilized Beryllium. Anal Chem 2015; 87:6814-21. [PMID: 26041094 DOI: 10.1021/acs.analchem.5b01035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The unique properties associated with beryllium metal ensures the continued use in many industries despite the documented health and environmental risks. While engineered safeguards and personal protective equipment can reduce risks associated with working with the metal, it has been mandated by the Environmental Protection Agency (EPA) and Occupational Safety and Health Administration (OSHA) that the workplace air and surfaces must be monitored for toxic levels. While many methods have been developed to monitor levels down to the low μg/m(3), the complexity and expense of these methods have driven the investigation into alternate methodologies. Herein, we use a combination of the previously developed fluorescence Be(II) ion detection reagent, 10-hydroxybenzo[h]quinoline (HBQ), with an optical field enhanced silicon nanopillar array, creating a new surface immobilized (si-HBQ) platform. The si-HBQ platform allows the positive control of the reagent for demonstrated reusability and a pillar diameter based tunable enhancement. Furthermore, native silicon nanopillars are overcoated with thin layers of porous silicon oxide to develop an analytical platform capable of a 0.0006 μg/L limit of detection (LOD) using sub-μL sample volumes. Additionally, we demonstrate a method to multiplex the introduction of the sample to the platform, with minimal 5.2% relative standard deviation (RSD) at 0.1 μg/L, to accommodate the potentially large number of samples needed to maintain industrial compliance. The minimal sample and reagent volumes and lack of complex and highly specific instrumentation, as well as positive control and reusability of traditionally consumable reagents, create a platform that is accessible and economically advantageous.
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Affiliation(s)
- Jennifer J Charlton
- †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States.,‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States
| | - Natalie C Jones
- ‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States.,∥Northern Arizona University, College of Engineering, Forestry, and Natural Sciences, Flagstaff, Arizona 86011, United States
| | - Ryan A Wallace
- †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States
| | - Robert W Smithwick
- ‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States
| | - James A Bradshaw
- †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States.,‡Y-12 National Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States
| | - Ivan I Kravchenko
- §The Center for Nanophase Material Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Nickolay V Lavrik
- §The Center for Nanophase Material Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Michael J Sepaniak
- †The University of Tennessee Knoxville, Department of Chemistry, Knoxville, Tennessee 37996, United States
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Wallace RA, Charlton JJ, Kirchner TB, Lavrik NV, Datskos PG, Sepaniak MJ. Superhydrophobic Analyte Concentration Utilizing Colloid-Pillar Array SERS Substrates. Anal Chem 2014; 86:11819-25. [DOI: 10.1021/ac5033947] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Ryan A. Wallace
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Jennifer J. Charlton
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
- Y-12 National
Security Complex, Analytical Chemistry Organization, Oak Ridge, Tennessee 37830, United States
| | - Teresa B. Kirchner
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Nickolay V. Lavrik
- Center for Nanophase
Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Panos G. Datskos
- Engineering Technology
Division, Oak Ridge National Laboratory, Oak
Ridge, Tennessee 37830, United States
| | - Michael J. Sepaniak
- Department
of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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Charlton JJ, Lavrik N, Bradshaw JA, Sepaniak MJ. Wicking nanopillar arrays with dual roughness for selective transport and fluorescence measurements. ACS APPLIED MATERIALS & INTERFACES 2014; 6:17894-17901. [PMID: 25247442 DOI: 10.1021/am504604j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Silicon nanopillars are important building elements for innovative nanoscale systems with unique optical, wetting, and chemical separation functionalities. However, technologies for creating expansive pillars arrays on the submicron scale are often complex and with practical time, cost, and method limitations. Herein we demonstrate the rapid fabrication of nanopillar arrays using the thermal dewetting of Pt films with thicknesses in the range from 5 to 19 nm followed by anisotropic reactive ion etching (RIE) of the substrate materials. A second level of roughness on the sub-30 nm scale is added by overcoating the silicon nanopillars with a conformal layer of porous silicon oxide (PSO) using room temperature plasma enhanced chemical vapor deposition (PECVD). This technique produced environmentally conscious, economically feasible, expansive nanopillar arrays with a production pathway scalable to industrial demands. The arrays were systematically analyzed for size, density, and variability of the pillar dimensions. We show that these stochastic arrays exhibit rapid wicking of various fluids and, when functionalized with a physiosorbed layer of silicone oil, act as a superhydrophobic surface. We also demonstrate high brightness fluorescence and selective transport of model dye compounds on surfaces of the implemented nanopillar arrays with two-tier roughness. The demonstrated combination of functionalities creates a platform with attributes inherently important for advanced separations and chemical analysis.
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Affiliation(s)
- Jennifer J Charlton
- The University of Tennessee Knoxville , Department of Chemistry, Knoxville, Tennessee 37996, United States
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Morlock GE. Miniaturized planar chromatography using office peripherals--office chromatography. J Chromatogr A 2014; 1382:87-96. [PMID: 25442326 DOI: 10.1016/j.chroma.2014.09.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 11/26/2022]
Abstract
Office chromatography (OC) harnesses the novel combination of miniaturized planar separation science and modern print & media technologies. Interdisciplinary knowledge is the essence: Printing of solutions on powerful miniaturized planar separation materials in combination with image capturing and evaluation tools enables an innovative analytical online system. Site-specific printing as lines or areas on defined sections of the layer comprises important steps like application of samples, feeding of the mobile phase as well as supply of the derivatization reagent. Also printing of bioassays can be combined for effect-directed detections and the homogeneous printing of the ultrathin layer itself, enabling tailor-made gradient-layer or multi-layer plates. OC exploits image-giving miniaturized chromatograms being captured and processed with a flatbed scanner or mini-camera. Thus, miniaturized separation materials are the core of OC. Monolithic, electrospun, nanostructured glancing angle deposition and carbon nanotube-templated microfabricated layers or even pillar arrays or polymer brush coated sub-μm silica particles were demonstrated, showing promising results. Layer thicknesses from 50 μm down to few micrometers were explored. A high-throughput capacity is given through the parallel development of as many as possible tiny-printed samples on the separation material. The migration time was reduced to a few minutes and the calculated analysis time per sample lasted few seconds. Considering a substantially reduced solvent consumption at short run times for parallel analysis of numerous samples at the same time, OC is an appropriate analytical technique for green chemistry. OC facilitates the whole planar separation process to be performed with no other equipment but a combined device of printer and flatbed scanner or mini-camera. At the same time, OC can be expected to become a widespread and economical technique with the user-friendliness of high-end office tools, appealing to users.
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Affiliation(s)
- Gertrud E Morlock
- Food Science, Justus Liebig University Giessen, Interdisciplinary Research Centre (IFZ) and Institute of Nutritional Science, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.
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