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Li MWH, She J, Zhu H, Li Z, Fan X. Microfabricated porous layer open tubular (PLOT) column. LAB ON A CHIP 2019; 19:3979-3987. [PMID: 31659362 DOI: 10.1039/c9lc00886a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Development of micro gas chromatography (μGC) is aimed at rapid and in situ analysis of volatile organic compounds (VOCs) for environmental protection, industrial monitoring, and toxicology. However, due to the lack of appropriate microcolumns and associated stationary phases, current μGC is unable to separate highly volatile chemicals such as methane, methanol, and formaldehyde, which are of great interest for their high toxicity and carcinogenicity. This inability has significantly limited μGC field applicability. To address this deficiency, this paper reports the development and characterization of a microfabricated porous layer open tubular (μPLOT) column with a divinylbenzene-based stationary phase. The separation capabilities of the μPLOT column are demonstrated by three distinct analyses of light alkanes, formaldehyde solution, and organic solvents, exhibiting its general utility for a wide range of highly volatile compounds. Further characterization shows the robust performance of the μPLOT column in the presence of high moisture and at high temperatures (up to 300 °C). The small footprint and the ability to separate highly volatile chemicals make the μPLOT column highly suitable for integration into μGC systems, thus significantly broadening μGC's applicability to rapid, field analysis of VOCs.
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Affiliation(s)
- Maxwell Wei-Hao Li
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. and Center for Wireless Integrated MicroSensing and Systems (WIMS2), University of Michigan, Ann Arbor, MI 48109, USA and Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jinyan She
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. and Center for Wireless Integrated MicroSensing and Systems (WIMS2), University of Michigan, Ann Arbor, MI 48109, USA
| | - Hongbo Zhu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. and Center for Wireless Integrated MicroSensing and Systems (WIMS2), University of Michigan, Ann Arbor, MI 48109, USA
| | - Ziqi Li
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. and School of Precision Instruments and Opto-electronics Engineering, Tianjin University, P. R. China
| | - Xudong Fan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA. and Center for Wireless Integrated MicroSensing and Systems (WIMS2), University of Michigan, Ann Arbor, MI 48109, USA
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Liu X, Azhar I, Khan H, Qu Q, Tian M, Yang L. Capillary electrophoresis-immobilized enzyme microreactors for acetylcholinesterase assay with surface modification by highly-homogeneous microporous layer. J Chromatogr A 2019; 1609:460454. [PMID: 31443966 DOI: 10.1016/j.chroma.2019.460454] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/04/2019] [Accepted: 08/12/2019] [Indexed: 12/31/2022]
Abstract
We propose a new capillary electrophoresis (CE)-based open-tubular immobilized enzyme microreactor (OT-IMER) and its application in acetylcholinesterase (AChE) assays. The IMER is fabricated at the capillary inlet (reactor length of ∼1 cm) with the inner surface modified by a micropore-structured layer (thickness of ∼220 nm, pore size of ∼15-20 nm). The use of IMER accomplishes the enzymatic reaction and separation/detection of the products in the same capillary within 3 min. The feasibility of the proposed method is evaluated via online analysis of the activity and inhibition of AChE enzymes. Such method exhibits good reproducibility with relative standard deviation (RSD) of less than 4% for 20 runs, and the enzyme remains over 82% of the initial activity after usage of 7 days. The IMERs are successfully applied to detect the organophosphorus pesticide, paraoxon, in three types of vegetable juice samples with a limit of detection of as low as 61 ng mL-1. Results show that the spiked samples are in the range of 89.6-105.9% with RSD less than 2.7%, thereby indicating its satisfactory level of accurate and reliable analysis of real samples by using the proposed method. Our study indicates that, with combination of advantages of both porous-layer capillary and CE OT-IMER, the proposed method is capable to enhance enzymatic reactions and to achieve rapid analysis with simple instrumentation and operation, thus would pave the way for extensive application of CE-based IMERs in a variety of bioanalysis.
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Affiliation(s)
- Xin Liu
- Key Laboratory of Nanobiosensing and Nanobioanalysis at Universities of Jilin Province, Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province, 130024, China
| | - Irfan Azhar
- Key Laboratory of Nanobiosensing and Nanobioanalysis at Universities of Jilin Province, Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province, 130024, China
| | - Habib Khan
- Key Laboratory of Nanobiosensing and Nanobioanalysis at Universities of Jilin Province, Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province, 130024, China
| | - Qishu Qu
- Key Laboratory of Functional Molecule Design and Interface Process, School of Materials and Chemical Engineering, Anhui Jianzhu University, Hefei, 230601, China
| | - Miaomiao Tian
- Institute of Chemical and Industrial Bioengineering, Jilin Engineering Normal University, Changchun, Jilin Province, 130052, China.
| | - Li Yang
- Key Laboratory of Nanobiosensing and Nanobioanalysis at Universities of Jilin Province, Department of Chemistry, Northeast Normal University, 5268 Renmin Street, Changchun, Jilin Province, 130024, China.
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