1
|
Thamatam N, Ahn J, Chowdhury M, Sharma A, Gupta P, Marr LC, Nazhandali L, Agah M. A MEMS-enabled portable gas chromatography injection system for trace analysis. Anal Chim Acta 2023; 1261:341209. [PMID: 37147055 DOI: 10.1016/j.aca.2023.341209] [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: 12/21/2022] [Revised: 03/18/2023] [Accepted: 04/10/2023] [Indexed: 05/07/2023]
Abstract
Growing concerns about environmental conditions, public health, and disease diagnostics have led to the rapid development of portable sampling techniques to characterize trace-level volatile organic compounds (VOCs) from various sources. A MEMS-based micropreconcentrator (μPC) is one such approach that drastically reduces the size, weight, and power constraints offering greater sampling flexibility in many applications. However, the adoption of μPCs on a commercial scale is hindered by a lack of thermal desorption units (TDUs) that easily integrate μPCs with gas chromatography (GC) systems equipped with a flame ionization detector (FID) or a mass spectrometer (MS). Here, we report a highly versatile μPC-based, single-stage autosampler-injection unit for traditional, portable, and micro-GCs. The system uses μPCs packaged in 3D-printed swappable cartridges and is based on a highly modular interfacing architecture that allows easy-to-remove, gas-tight fluidic, and detachable electrical connections (FEMI). This study describes the FEMI architecture and demonstrates the FEMI-Autosampler (FEMI-AS) prototype (9.5 cm × 10 cm x 20 cm, ≈500 gms). The system was integrated with GC-FID, and the performance was investigated using synthetic gas samples and ambient air. The results were contrasted with the sorbent tube sampling technique using TD-GC-MS. FEMI-AS could generate sharp injection plugs (≈240 ms) and detect analytes with concentrations <15 ppb within 20 s and <100 ppt within 20 min of sampling time. With more than 30 detected trace-level compounds from ambient air, the demonstrated FEMI-AS, and the FEMI architecture significantly accelerate the adoption of μPCs on a broader scale.
Collapse
Affiliation(s)
- Nipun Thamatam
- VT MEMS Lab, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States
| | - Jeonghyeon Ahn
- VT MEMS Lab, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States; Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States
| | - Mustahsin Chowdhury
- VT MEMS Lab, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States
| | - Arjun Sharma
- CESCA, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States
| | - Poonam Gupta
- CESCA, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States
| | - Linsey C Marr
- Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States
| | - Leyla Nazhandali
- CESCA, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States
| | - Masoud Agah
- VT MEMS Lab, The Bradley Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24061, United States.
| |
Collapse
|
2
|
The Application of In Situ Methods to Monitor VOC Concentrations in Urban Areas—A Bibliometric Analysis and Measuring Solution Review. SUSTAINABILITY 2022. [DOI: 10.3390/su14148815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Urbanisation development affects urban vegetation both directly and indirectly. Since this process usually involves a dramatic change in land use, it is seen as likely to cause ecological pressure on local ecosystems. All forms of human activity, including urbanisation of areas close to residential buildings, significantly impact air quality. This study aims to identify and characterise different measurement solutions of VOCs, allowing the quantification of total and selective compounds in a direct at source (in situ) manner. Portable devices for direct testing can generally be divided into detectors, chromatographs, and electronic noses. They differ in parameters such as operating principle, sensitivity, measurement range, response time, and selectivity. Direct research allows us to obtain measurement results in a short time, which is essential from the point of view of immediate reaction in the case of high concentrations of tested compounds and the possibility of ensuring the well-being of people. The paper also attempts to compare solutions and devices available on the market and assess their application.
Collapse
|
3
|
Built-in Chamber-Coupled Electronic Pressure Control of Ambient Air as the Carrier Gas for a Cylinder-Free Portable Gas Chromatograph. Chromatographia 2021. [DOI: 10.1007/s10337-021-04108-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
4
|
Skog KM, Xiong F, Kawashima H, Doyle E, Soto R, Gentner DR. Compact, Automated, Inexpensive, and Field-Deployable Vacuum-Outlet Gas Chromatograph for Trace-Concentration Gas-Phase Organic Compounds. Anal Chem 2019; 91:1318-1327. [DOI: 10.1021/acs.analchem.8b03095] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Kate M. Skog
- Department of Chemical & Environmental Engineering, School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States
| | - Fulizi Xiong
- Department of Chemical & Environmental Engineering, School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States
| | - Hitoshi Kawashima
- Department of Chemical & Environmental Engineering, School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States
| | - Evan Doyle
- Department of Chemical & Environmental Engineering, School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States
| | - Ricardo Soto
- Department of Chemical & Environmental Engineering, School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States
| | - Drew R. Gentner
- Department of Chemical & Environmental Engineering, School of Engineering and Applied Science, Yale University, New Haven, Connecticut 06511, United States
- SEARCH (Solutions for Energy, Air, Climate and Health) Center, Yale University, New Haven, Connecticut 06511, United States
| |
Collapse
|
5
|
Characterization of thermal desorption with the Deans-switch technique in gas chromatographic analysis of volatile organic compounds. J Chromatogr A 2016; 1462:107-14. [PMID: 27492597 DOI: 10.1016/j.chroma.2016.07.070] [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: 05/05/2016] [Revised: 07/26/2016] [Accepted: 07/26/2016] [Indexed: 11/23/2022]
Abstract
This study presents a novel application based on the Deans-switch cutting technique to characterize the thermal-desorption (TD) properties for gas chromatographic (GC) analysis of ambient volatile organic compounds (VOCs). Flash-heating of the sorbent bed at high temperatures to desorb trapped VOCs to GC may easily produce severe asymmetric or tailing GC peaks affecting resolution and sensitivity if care is not taken to optimize the TD conditions. The TD peak without GC separation was first examined for the quality of the TD peak by analyzing a standard gas mixture from C2 to C12 at ppb level. The Deans switch was later applied in two different stages. First, it was used to cut the trailing tail of the TD peak, which, although significantly improved the GC peak symmetry, led to more loss of the higher boiling compounds than the low boiling ones, thus suggesting compound discrimination. Subsequently, the Deans switch was used to dissect the TD peak into six 30s slices in series, and an uneven distribution in composition between the slices were found. A progressive decrease in low boiling compounds and increase in higher boiling ones across the slices indicated severe inhomogeneity in the TD profile. This finding provided a clear evidence to answer the discrimination problem found with the tail cutting approach to improve peak symmetry. Through the use of the innovated slicing method based on the Deans-switch cutting technique, optimization of TD injection for highly resolved, symmetric and non-discriminated GC peaks can now be more quantitatively assessed and guided.
Collapse
|
6
|
Bryant-Genevier J, Zellers ET. Toward a microfabricated preconcentrator-focuser for a wearable micro-scale gas chromatograph. J Chromatogr A 2015; 1422:299-309. [DOI: 10.1016/j.chroma.2015.10.045] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 10/14/2015] [Accepted: 10/14/2015] [Indexed: 10/22/2022]
|
7
|
Hybrid preconcentrator/focuser module for determinations of explosive marker compounds with a micro-scale gas chromatograph. J Chromatogr A 2013; 1279:76-85. [DOI: 10.1016/j.chroma.2013.01.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/03/2013] [Accepted: 01/04/2013] [Indexed: 11/21/2022]
|
9
|
Sukaew T, Chang H, Serrano G, Zellers ET. Multi-stage preconcentrator/focuser module designed to enable trace level determinations of trichloroethylene in indoor air with a microfabricated gas chromatograph. Analyst 2011; 136:1664-74. [DOI: 10.1039/c0an00780c] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
11
|
Sanchez JM, Sacks RD. Performance characteristics of a new prototype for a portable GC using ambient air as carrier gas for on-site analysis. J Sep Sci 2007; 30:1052-60. [PMID: 17566340 DOI: 10.1002/jssc.200600367] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The performance characteristics of a portable GC instrument requiring no compressed gas supplies and using relatively lightweight transportable components for the analysis of volatile organic components in large-volume air samples are described. To avoid the need for compressed gas tanks, ambient air is used as the carrier gas, and a vacuum pump is used to pull the carrier gas and injected samples through the wall-coated capillary column and a photoionization detector (PID). At-column heating is used eliminating the need for a conventional oven. The fused silica column is wrapped with heater wire and sensor wire so that heating is provided directly at the column. A PID is used since it requires no external gas supplies and has high sensitivity for many compounds of interest in environmental air monitoring. In order to achieve detection limits in the ppb range, an online multibed preconcentrator containing beds of graphitized carbons and carbon molecular sieves is used. After sample collection, the flow direction through the preconcentrator is reversed, and the sample is thermally desorbed directly into the column. Decomposition of sensitive compounds during desorption is greater with air as the carrier gas than with hydrogen.
Collapse
Affiliation(s)
- Juan M Sanchez
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA.
| | | |
Collapse
|