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Wabnitz C, Canavan A, Chen W, Reisbeck M, Bakkour R. Quartz Crystal Microbalance as a Holistic Detector for Quantifying Complex Organic Matrices during Liquid Chromatography: 1. Coupling, Characterization, and Validation. Anal Chem 2024; 96:7429-7435. [PMID: 38683884 PMCID: PMC11099895 DOI: 10.1021/acs.analchem.3c05440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
A matrix in highly complex samples can cause adverse effects on the trace analysis of targeted organic compounds. A suitable separation of the target analyte(s) and matrix before the instrumental analysis is often a vital step for which chromatographic cleanup methods remain one of the most frequently used strategies, particularly high-performance liquid chromatography (HPLC). The lack of a simple real-time detection technique that can quantify the entirety of the matrix during this step, especially with gradient solvents, renders optimization of the cleanup challenging. This paper, along with a companion one, explores the possibilities and limitations of quartz crystal microbalance (QCM) dry-mass sensing for quantifying complex organic matrices during gradient HPLC. To this end, this work coupled a QCM and a microfluidic spray dryer with a commercial HPLC system using a flow splitter and developed a calibration and data processing strategy. The system was characterized in terms of detection and quantification limits, with LOD = 4.3-15 mg/L and LOQ = 16-52 mg/L, respectively, for different eluent compositions. Validation of natural organic matter in an environmental sample against offline total organic carbon analysis confirmed the approach's feasibility, with an absolute recovery of 103 ± 10%. Our findings suggest that QCM dry-mass sensing could serve as a valuable tool for analysts routinely employing HPLC cleanup methods, offering potential benefits across various analytical fields.
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Affiliation(s)
- Christopher Wabnitz
- TUM School of Natural Sciences, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Garching 85748, Germany
| | - Aoife Canavan
- TUM School of Natural Sciences, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Garching 85748, Germany
| | - Wei Chen
- TUM School of Natural Sciences, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Garching 85748, Germany
| | - Mathias Reisbeck
- TUM School of Computation, Information and Technology, Heinz Nixdorf Chair of Biomedical Electronics, Technical University of Munich, Munich 81675, Germany
| | - Rani Bakkour
- TUM School of Natural Sciences, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Garching 85748, Germany
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Wabnitz C, Chen W, Elsner M, Bakkour R. Quartz Crystal Microbalance as a Holistic Detector for Quantifying Complex Organic Matrices during Liquid Chromatography: 2. Compound-Specific Isotope Analysis. Anal Chem 2024; 96:7436-7443. [PMID: 38700939 PMCID: PMC11099894 DOI: 10.1021/acs.analchem.3c05441] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/22/2024] [Accepted: 04/17/2024] [Indexed: 05/05/2024]
Abstract
In carbon-compound-specific isotope analysis (carbon CSIA) of environmental micropollutants, purification of samples is often required to guarantee accurate measurements of a target compound. A companion paper has brought forward an innovative approach to couple a quartz crystal microbalance (QCM) with high-performance liquid chromatography (HPLC) for the online quantification of matrices during a gradient HPLC purification. This work investigates the benefit for isotope analysis of polar micropollutants typically present in environmental samples. Here, we studied the impact of the natural organic matter (NOM) on the isotopic integrity of model analytes and the suitability of the NOM-to-analyte ratio as a proxy for the sample purity. We further investigated limitations and enhancement of HPLC purification using QCM on C18 and C8 phases for single and multiple targets. Strong isotopic shifts of up to 3.3% toward the isotopic signature of NOM were observed for samples with an NOM-to-analyte ratio ≥10. Thanks to QCM, optimization of matrix removal of up to 99.8% of NOM was possible for late-eluting compounds. The efficiency of HPLC purification deteriorated when aiming for simultaneous purification of two or three compounds, leading to up to 2.5% less NOM removal. Our results suggest that one optimized HPLC purification can be achieved through systematic screening of 3 to 5 different gradients, thereby leading to a shift of the boundaries of accurate carbon CSIA by up to 2 orders of magnitude toward lower micropollutant concentrations.
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Affiliation(s)
- Christopher Wabnitz
- Department of Chemistry, Chair of Analytical
Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Wei Chen
- Department of Chemistry, Chair of Analytical
Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Martin Elsner
- Department of Chemistry, Chair of Analytical
Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Rani Bakkour
- Department of Chemistry, Chair of Analytical
Chemistry and Water Chemistry, TUM School of Natural Sciences, Technical University of Munich, Lichtenbergstr. 4, 85748 Garching, Germany
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Qian R, Sun C, Bai T, Yan J, Cheng J, Zhang J. Recent advances and challenges in the interaction between myofibrillar proteins and flavor substances. Front Nutr 2024; 11:1378884. [PMID: 38725578 PMCID: PMC11079221 DOI: 10.3389/fnut.2024.1378884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/15/2024] [Indexed: 05/12/2024] Open
Abstract
Myofibrillar proteins are an important component of proteins. Flavor characteristics are the key attributes of food quality. The ability of proteins to bind flavor is one of their most fundamental functional properties. The dynamic balance of release and retention of volatile flavor compounds in protein-containing systems largely affects the sensory quality and consumer acceptability of foods. At present, research on flavor mainly focuses on the formation mechanism of flavor components, while there are few reports on the release and perception of flavor components. This review introduces the composition and structure of myofibrillar proteins, the classification of flavor substances, the physical binding and chemical adsorption of myofibrillar proteins and volatile flavor substances, as well as clarifies the regulation law of flavor substances from the viewpoint of endogenous flavor characteristics and exogenous environment factors, to provide a theoretical reference for the flavor regulation of meat products.
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Affiliation(s)
- Rong Qian
- College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Chang Sun
- College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Ting Bai
- College of Food and Biological Engineering, Chengdu University, Chengdu, China
- Meat Processing Key Laboratory of Sichuan Province, Chengdu, China
| | - Jing Yan
- Sichuan Laochuan East Food Co., Ltd., Chengdu, China
| | - Jie Cheng
- College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Jiamin Zhang
- Meat Processing Key Laboratory of Sichuan Province, Chengdu, China
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Wiita EG, Toprakcioglu Z, Jayaram AK, Knowles TPJ. Selenium-silk microgels as antifungal and antibacterial agents. NANOSCALE HORIZONS 2024; 9:609-619. [PMID: 38288551 PMCID: PMC10962633 DOI: 10.1039/d3nh00385j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 11/29/2023] [Indexed: 03/26/2024]
Abstract
Antimicrobial resistance is a leading threat to global health. Alternative therapeutics to combat the rise in drug-resistant strains of bacteria and fungi are thus needed, but the development of new classes of small molecule therapeutics has remained challenging. Here, we explore an orthogonal approach and address this issue by synthesising micro-scale, protein colloidal particles that possess potent antimicrobial properties. We describe an approach for forming silk-based microgels that contain selenium nanoparticles embedded within the protein scaffold. We demonstrate that these materials have both antibacterial and antifungal properties while, crucially, also remaining highly biocompatible with mammalian cell lines. By combing the nanoparticles with silk, the protein microgel is able to fulfill two critical functions; it protects the mammalian cells from the cytotoxic effects of the bare nanoparticles, while simultaneously serving as a carrier for microbial eradication. Furthermore, since the antimicrobial activity originates from physical contact, bacteria and fungi are unlikely to develop resistance to our hybrid biomaterials, which remains a critical issue with current antibiotic and antifungal treatments. Therefore, taken together, these results provide the basis for innovative antimicrobial materials that can target drug-resistant microbial infections.
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Affiliation(s)
- Elizabeth G Wiita
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lenseld Road, Cambridge CB2 1EW, UK.
| | - Zenon Toprakcioglu
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lenseld Road, Cambridge CB2 1EW, UK.
| | - Akhila K Jayaram
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lenseld Road, Cambridge CB2 1EW, UK.
- Cavendish Laboratory, Department of Physics, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK
| | - Tuomas P J Knowles
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lenseld Road, Cambridge CB2 1EW, UK.
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Al-Hakkani MF, Ahmed N, Hassan MHA. Rapidly, sensitive quantitative assessment of thiopental via forced stability indicating validated RP-HPLC method and its in-use stability activities. Sci Rep 2023; 13:10294. [PMID: 37357256 DOI: 10.1038/s41598-023-37329-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/20/2023] [Indexed: 06/27/2023] Open
Abstract
Thiopental sodium (Tho) is an intravenous anesthetic. The current study aimed to find a rapid RP-HPLC method of Tho analysis with high linearity, repeatability, sensitivity, selectivity, and inexpensive. In our developed method, there is no need to use special chemical reagents, a high percentage of organic solvent, a high flow rate, or a further guard column. The chromatographic system consists of an ODS column (150 mm × 4.6 mm × 5 μm). The mobile phase was prepared by mixing KH2PO4 solution: methanol (40:60) with a flow rate of 1.2 mL/min at a detection wavelength of 230 nm, at room temperature using an injection volume of 10 μL. The method manifested a satisfied linearity regression R2 (0.9997) with a good repeatability precision range (0.16-0.47%) with LOD and LOQ; 14.4 μg/mL and 43.6 μg/mL respectively. Additionally, the method proved its efficiency via system suitability achievement in robustness and ruggedness, according to the validation guidelines. The shorter analysis time makes the method very valuable in quality control to quantify the commercial Tho in pharmaceutical preparations. This improved HPLC method has been successfully applied for Tho analysis for Thiopental UP Pharma 500 mg vials and Thiopental Eipico 1.0 g vials in our routine finished and stability studies testing laboratories. Additionally, the detection limit of Tho has been tested in our quality control lab to detect the smallest amount of traces that may be present after the cleaning process of the production machines for cephalosporins preparations. The method has shown positive results for Tho in low-level raw materials and pharmaceutical formulations.
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Affiliation(s)
- Mostafa F Al-Hakkani
- Department of Chemistry, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut, 71524, Egypt.
- Department of Research, Development, and Stability, UP Pharma, Industrial Zone, Arab El Awamer, Abnoub, 76, Assiut, Egypt.
| | - Nourhan Ahmed
- Department of Research, Development, and Stability, UP Pharma, Industrial Zone, Arab El Awamer, Abnoub, 76, Assiut, Egypt
| | - Mohammad H A Hassan
- Department of Medical Laboratory Technology, Higher Technological Institute for Applied Health Sciences in Minya, Minya, Egypt
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Zhan H, Hao M, Lin E, Zheng Z, Huang C, Cai S, Cao S, Huang Y, Chen Z. A Pure Shift-Based Nuclear Magnetic Resonance Method for In-Phase Three-Dimensional Diffusion-Ordered Spectroscopy. Anal Chem 2023; 95:1002-1007. [PMID: 36579454 DOI: 10.1021/acs.analchem.2c03678] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY) plays a vital role in mixture studies. However, its applications to complex mixture samples are generally limited by spectral congestion along the chemical shift domain caused by extensive J coupling networks and abundant compounds. Herein, we develop the in-phase multidimensional DOSY strategy for complex mixture analyses by simultaneously revealing molecular self-diffusion behaviors and multiplet structures with optimal spectral resolution. As a proof of concept, two pure shift-based three-dimensional (3D) DOSY protocols are proposed to record high-resolution 3D spectroscopic view with separated mixture components and their resolved multiplet coupling structures, thus suitable for analyzing complex mixtures that contain abundant compounds and complicated molecular structures, even under adverse magnetic field conditions. Therefore, this study shows a promising tool for component analyses and multiplet structure studies on practical mixture samples.
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Affiliation(s)
- Haolin Zhan
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China.,Department of Biomedical Engineering, Anhui Provincial Key Laboratory of Measuring Theory and Precision Instrument, School of Instrument Science and Optoelectronics Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Mengyou Hao
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Enping Lin
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zeyu Zheng
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Chengda Huang
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Shuhui Cai
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Shuohui Cao
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yuqing Huang
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhong Chen
- Department of Electronic Science, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
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Mavrakis E, Toprakcioglu Z, Lydakis-Simantiris N, Knowles TPJ, Pergantis SA. A chip-based supersonic microfluidic nebulizer for efficient sample introduction into inductively coupled plasma - Mass spectrometry. Anal Chim Acta 2022; 1229:340342. [PMID: 36156219 DOI: 10.1016/j.aca.2022.340342] [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: 12/01/2021] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 11/29/2022]
Abstract
As the use of microfluidic chips for handling biological samples is increasing, so is the need for combining them with powerful analytical techniques for metal determination such as inductively-coupled plasma mass spectrometry (ICP-MS). So far, coupling a microfluidic chip to an ICP-MS has been demonstrated mainly through the use of conventional pneumatic micro-flow nebulizers. However, disadvantages associated with the use of such nebulizers entail dead volume issues and liquid suction exerted on the outlet channel of the chip. Herein, we propose that a microfluidic chip, bearing a pneumatic nozzle for liquid nebulization, has the potential to advance metal determination in chip-based ICP-MS. More specifically, we demonstrate for the first time that the coupling of a chip-based supersonic microfluidic nebulizer (chip-μf-Neb) to an ICP-MS can be conveniently achieved through the use of a spray chamber with a laminar flow makeup gas. Operation of the combined system was evaluated at low liquid flow rates across 0.5-20 μL min-1, while nebulization and makeup argon (Ar) gas flow rates were optimized with respect to maximizing indium (In) sensitivity and minimizing oxide formation; a maximum sensitivity of 40000 cps (μg L-1)-1 was achieved at 10 μL min-1. The system was further evaluated for its performance in single-particle analysis, featuring a transport efficiency of 46% for Ag nanoparticles. Finally, the capabilities for conducting single-cell analysis were demonstrated with the detection of 80Se and 75As in individual Chlamydomas reinhardtii cells, which were previously incubated in 20 μM of selenate and 300 μM of arsenate, respectively. Efficient operation at low liquid flow rates along with the absence of self-aspiration render this nebulizer a promising tool for combining the powerful field of microfluidics with metal quantitation by means of ICP-MS.
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Affiliation(s)
- E Mavrakis
- Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, Voutes Campus, Heraklion, 70013, Greece
| | - Z Toprakcioglu
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - N Lydakis-Simantiris
- Laboratory of Biological & Biotechnological Applications, Department of Agriculture, Hellenic Mediterranean University, Estavromenos, Heraklion, 71410, Greece; Hellenic Mediterranean University Research Center, Institute of Agri-food and Life Sciences, Heraklion, Crete, Greece
| | - T P J Knowles
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom; Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom.
| | - S A Pergantis
- Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, Voutes Campus, Heraklion, 70013, Greece.
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8
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Affinity-Recognition-Based Gravimetric Nanosensor for Equilin Detection. CHEMOSENSORS 2022. [DOI: 10.3390/chemosensors10050172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
The estrogenic hormones that are widely used in postmenopausal hormone supplements for women contaminate natural water resources. Equilin (Equ) is one of the estrogenic hormones that have a maximum contaminant level of 0.35 µg/L in the chemical pollutants list. In this study, estrogenic hormones were precisely detected in a short time by affinity-recognition-based interactions in Quartz Crystal Microbalance (QCM) sensors. The QCM sensors were modified with 11-mercaptoundecanoic acid forming a self-assembled monolayer and with amino acids, namely tyrosine, tryptophan and phenylalanine. The affinity interactions between Equ and amino acids were studied using docking tools and confirmed by QCM experiments. The LODs of Equ were obtained as 4.59, 5.05 and 6.30 ng/L for tyrosine-, tryptophan- and phenylalanine-modified QCM nanosensors, respectively, with linear dynamic detection in the range of 25–500 nM. In terms of the LOD, selectivity and sensitivity calculations, the tyrosine-modified QCM nanosensor was found to have the highest performance for Equ detection compared to the tryptophan- and phenylalanine-modified ones.
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Hu J, Yesilbas G, Li Y, Geng X, Li P, Chen J, Wu X, Knoll A, Ren TL. Exploration of the Mass Sensitivity of Quartz Crystal Microbalance under Overtone Modes Using Electrodeposition Method. Anal Chem 2022; 94:5760-5768. [PMID: 35377148 DOI: 10.1021/acs.analchem.1c04648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
With the in-depth application of quartz crystal microbalance (QCM) sensors in the fields of science and engineering, there is an urgent need for QCM sensors with high mass sensitivity. The mass sensitivity of a QCM is closely related to its resonance frequency, and the high resonance frequency leads to improve its mass sensitivity. However, the resonance frequency of a QCM resonator cannot be increased all the time due to the fragility of quartz wafer and the limits of energy trapping effect. Few studies are associated with mass sensitivity of a QCM resonator under overtone modes. Herein, we propose to make a QCM resonator work in its n-th overtone (n = 3, 5, 7, 9 in this study) mode to increase its resonance frequency during operating. Thereby, the purpose of improving QCM mass sensitivity is achieved, and the mass sensitivity of a QCM working in the n-th overtone mode can be called as n-th overtone mass sensitivity. Then, the n-th overtone mass sensitivity of a QCM sensor is measured by an electrodeposition method. The experimental results show that the n-th overtone mass sensitivity of a QCM is a bit more than n times that of the fundamental mass sensitivity, and it is consistent with the theoretical calculation results. The application of overtone mass sensitivity will greatly improve the sensitivity of QCM sensors, which is very attractive for the research fields that require QCM sensors with high sensitivity.
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Affiliation(s)
- Jianguo Hu
- School of Integrated Circuits & Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China.,Institut für Informatik VI, Technische Universität München, München 85748, Germany
| | - Göktug Yesilbas
- Institut für Informatik VI, Technische Universität München, München 85748, Germany
| | - Yuanyuan Li
- School of Integrated Circuits & Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Xiangshun Geng
- School of Integrated Circuits & Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Ping Li
- School of Integrated Circuits & Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Jing Chen
- School of Integrated Circuits & Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Xiaoming Wu
- School of Integrated Circuits & Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
| | - Alois Knoll
- Institut für Informatik VI, Technische Universität München, München 85748, Germany
| | - Tian-Ling Ren
- School of Integrated Circuits & Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing 100084, China
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Inagawa A, Kimura M, Uehara N. Total protein assay by PCA-based RGB-spectrum conversion methods with smartphone-acquired digital images. ANAL SCI 2022; 38:869-880. [PMID: 35325437 DOI: 10.1007/s44211-022-00107-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/07/2022] [Indexed: 11/01/2022]
Abstract
Total protein concentrations in the aqueous solutions were determined from the absorption spectra reproduced from smartphone-captured digital color images. We employed two different procedures for protein determination: the pyrogallol red molybdate method and Bradford's method. The principal-component-analysis-based reproduction process, which was previously reported by our research group, enabled the conversion of RGB values to score values for a linear combination of loading vectors to generate reproduced absorption spectra. The reproduced spectra were identical to those measured using a commercially available spectrophotometer. The total protein assays of commercial soymilk and human serum samples were carried out with both coloration reagents, and the obtained results were in good agreement with those attained using a conventional spectrophotometer. These results show that the proposed method enables smartphone-based ratiometric analysis of real samples without requiring any monochromating equipment.
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Affiliation(s)
- Arinori Inagawa
- Faculty of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi, 321-8585, Japan.
| | - Miwa Kimura
- Faculty of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi, 321-8585, Japan
| | - Nobuo Uehara
- Faculty of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi, 321-8585, Japan.
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Chen Q, Huang X, Yao Y, Mao K. Analysis of the Effect of Electrode Materials on the Sensitivity of Quartz Crystal Microbalance. NANOMATERIALS 2022; 12:nano12060975. [PMID: 35335788 PMCID: PMC8954940 DOI: 10.3390/nano12060975] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/09/2022] [Accepted: 03/15/2022] [Indexed: 02/04/2023]
Abstract
This paper investigated the effect of electrode materials on the performance of quartz crystal microbalance (QCM) sensors by means of theoretical calculation, experiment, and finite element analysis methods. First, we calculated the particle displacement amplitude and thus obtained the mass sensitivity function distribution of QCMs with gold, silver and aluminum electrodes, and found that the QCM with the gold electrode has the highest mass sensitivity at the center of the electrode. Then, we tested the humidity-sensing performance of QCMs with gold, silver, and aluminum electrodes using graphene oxide (GO) as the sensitive material, and found that the QCM with the gold electrode has higher humidity sensitivity. Finally, we used the finite element analysis software COMSOL Multiphysics to simulate the specific electrode material parameters that affect the sensitivity of the QCMs. The simulation results show that the density and Young’s modulus of the electrode material parameters mainly affect the sensitivity. The results of this paper are instructive for optimizing QCM sensor performance and improving the capability of QCM quantitative analysis.
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Affiliation(s)
| | | | - Yao Yao
- Correspondence: (X.H.); (Y.Y.)
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12
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Li M, Peng X, Liu X, Wang H, Zhang S, Hu G. Single-atom niobium doped BCN nanotubes for highly sensitive electrochemical detection of nitrobenzene. RSC Adv 2021; 11:28988-28995. [PMID: 35478577 PMCID: PMC9038177 DOI: 10.1039/d1ra05517h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 08/24/2021] [Indexed: 12/16/2022] Open
Abstract
Herein, single-atom niobium-doped boron-carbon-nitrogen nanotubes (SANb-BCN) were synthesized and utilized to fabricate an electrochemical sensor for the detection of nitrobenzene (NB), an environmental pollutant. SANb-BCN were characterized through scanning transmission electron microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and Raman spectroscopy. The Nb-BNC material modified on a glassy carbon electrode (GCE) showed an excellent electrochemical response behavior toward NB. The SANb-BCN-modified GCE (SANb-BCN/GCE) gave rise to a prominent NB reduction peak at -0.6 V, which was positively shifted by 120 mV from the NB reduction peak of the bare GCE. Furthermore, the NB peak current (55.74 μA) obtained using SANb-BCN/GCE was nearly 42-fold higher than that using the bare GCE (1.32 μA), indicating that SANb-BCN/GCE is a highly sensitive electrochemical sensor for NB. An ultralow limit of detection (0.70 μM, S/N = 3) was also achieved. Furthermore, the SANb-BCN/GCE sensor was found to possess favorable anti-interference ability during NB detection; thus, the presence of various organic and inorganic coexisting species, including Mg2+, Cr6+, Cu2+, K+, Ca2+, NH4+, Cd2+, urea, 1-bromo-4-nitrobenzene, 3-hydroxybenzoic, terephthalic acid, 1-iodo-4-nitrobenzene, and toluene, minimally affected the NB detection signal. Notably, the SANb-BNC sensor material exhibited high sensitivity and specificity toward detection of NB in environmental samples. Thus, the use of the proposed sensor will serve as an effective alternative method for the identification and treatment of pollutants.
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Affiliation(s)
- Meng Li
- College of Chemistry, Zhengzhou University Zhengzhou 450000 China
| | - Xianyun Peng
- Institute for New Energy Materials and Low-Carbon Technologies, Tianjin University of Technology Tianjin 300384 China
| | - Xijun Liu
- Institute for New Energy Materials and Low-Carbon Technologies, Tianjin University of Technology Tianjin 300384 China
| | - Huaisheng Wang
- School of Chemistry and Chemical Engineering, Liaocheng University Liaocheng 252000 China
| | - Shusheng Zhang
- College of Chemistry, Zhengzhou University Zhengzhou 450000 China
| | - Guangzhi Hu
- College of Chemistry, Zhengzhou University Zhengzhou 450000 China
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University Kunming 650504 China
- College of Biological, Chemical Sciences and Engineering, Jiaxing University Jiaxing Zhejiang 314001 China
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