Axial thermal gradients in microchip gas chromatography

Wang, Anzi; Hynynen, Sampo; Hawkins, Aaron R.; Tolley, Samuel E.; Tolley, H. Dennis; Lee, Milton L.

doi:10.1016/j.chroma.2014.11.035

Cited by 32 publications

(21 citation statements)

References 34 publications

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“…The SEM images shown in the Supporting Information, however, suggest we suffer from the same type of stationary phase pooling in the corners of the channel as reported in many other microchip-GC studies. 23,29,32 It is logical to assume the pooling in the corners of the channels will lead to a layer that is thinner than expected in the middle of the walls.…”

Section: ■ Resultsmentioning

confidence: 99%

Chip-Based Multicapillary Column with Maximal Interconnectivity to Combine Maximum Efficiency and Maximum Loadability

et al. 2017

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On the basis of our previous work on the design of pillar array columns for liquid chromatography, we report on a new pillar array design for high-efficiency, high volumetric loadability gas chromatography columns. The proposed pillar array configuration leads to a column design which can either be considered as a packed bed with perfectly ordered and uniform flow paths or as multicapillary columns (8 parallel tracks) with a maximal interconnectivity between the flow paths to avoid the so-called polydispersity effect (dispersion arising from the inevitable differences in migration velocity between parallel flow paths). Despite our relative inexperience with column coating, and most probably (not supported by data) suffering from the same problem of stationary phase pooling in the right-angled corners of the flow-through channels as other chip-based GC devices, the efficiencies obtained in a L = 70 cm long and 75 μm deep and 6.195 mm wide chip for, respectively, quasi-unretained and retained components (k = 7) went up to N = 60 000 and 12 500 under isothermal conditions using H as carrier gas and a downstream restriction. Under programmed temperature conditions (T = 80 °C, T = 175 °C at 30 °C/min, and a H flow of 0.4 mL/min), a peak capacity of 170 was obtained in 3.6 min. For retained compounds, the optimal flow rate is found to be on the order of 0.4 mL/min, achieved at an operating pressure of 2.3 bar. Intrinsically, the column combines the efficiency of a 75 μm capillary with the volumetric loadability of a 240 μm capillary.

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Section: ■ Resultsmentioning

confidence: 99%

Chip-Based Multicapillary Column with Maximal Interconnectivity to Combine Maximum Efficiency and Maximum Loadability

et al. 2017

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“…A variety of µGC components have been reported, typically as standalone elements: preconcentrators [ 35 ], valves [ 36 , 37 ], separation columns [ 38 , 39 , 40 ], detectors [ 41 , 42 , 43 , 44 , 45 , 46 ], and pumps [ 47 , 48 , 49 ]. In the PCA3mv, Cell 2 and Cell 3 each used a monolithic chip that integrated a preconcentrator, a separation column, and a T-connector ( Figure 3 a); Cell 1 did not use a monolithic chip as the coating method for the Column1 stationary phase has not been developed.…”

Section: Design and Implementationmentioning

confidence: 99%

Progressive Cellular Architecture in Microscale Gas Chromatography for Broad Chemical Analyses

Liao

Zhao

et al. 2021

Sensors

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Gas chromatography is widely used to identify and quantify volatile organic compounds for applications ranging from environmental monitoring to homeland security. We investigate a new architecture for microfabricated gas chromatography systems that can significantly improve the range, speed, and efficiency of such systems. By using a cellular approach, it performs a partial separation of analytes even as the sampling is being performed. The subsequent separation step is then rapidly performed within each cell. The cells, each of which contains a preconcentrator and separation column, are arranged in progression of retentiveness. While accommodating a wide range of analytes, this progressive cellular architecture (PCA) also provides a pathway to improving energy efficiency and lifetime by reducing the need for heating the separation columns. As a proof of concept, a three-cell subsystem (PCA3mv) has been built; it incorporates a number of microfabricated components, including preconcentrators, separation columns, valves, connectors, and a carrier gas filter. The preconcentrator and separation column of each cell are monolithically implemented as a single chip that has a footprint of 1.8 × 5.2 cm2. This subsystem also incorporates two manifold arrays of microfabricated valves, each of which has a footprint of 1.3 × 1.4 cm2. Operated together with a commercial flame ionization detector, the subsystem has been tested against polar and nonpolar analytes (including alkanes, alcohols, aromatics, and phosphonate esters) over a molecular weight range of 32–212 g/mol and a vapor pressure range of 0.005–231 mmHg. The separations require an average column temperature of 63–68 °C within a duration of 12 min, and provide separation resolutions >2 for any two homologues that differ by one methyl group.

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“…A recent review by Tranchida and Mondello [18] discusses the use of microbore capillary columns for fast GC, and another recent review by Wang et al [19] outlines the use of resistive heating for fast GC. Other techniques for rapid column heating, such as thermal gradient chromatography [20][21][22][23] have shown promise as novel technologies in the fast GC field. The results we present herein, as well as the results presented in previous references have important implications for two-dimensional gas chromatography (GC × GC or GC-GC) [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of injection methods for fast, high peak capacity separations with low thermal mass gas chromatography

Fitz

Mannion

et al. 2015

Journal of Chromatography A

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Axial thermal gradients in microchip gas chromatography

Cited by 32 publications

References 34 publications

Chip-Based Multicapillary Column with Maximal Interconnectivity to Combine Maximum Efficiency and Maximum Loadability

Chip-Based Multicapillary Column with Maximal Interconnectivity to Combine Maximum Efficiency and Maximum Loadability

Progressive Cellular Architecture in Microscale Gas Chromatography for Broad Chemical Analyses

Evaluation of injection methods for fast, high peak capacity separations with low thermal mass gas chromatography

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