Micro Gas Preconcentrator Made of a Film of Single-Walled Carbon Nanotubes

Abstract

The development of a micro gas preconcentrator is crucial for the realization of miniaturized gas chromatography (micro-GC) systems which are expected to open up new applications such as breath analysis. One of the major problems with the reduction of preconcentrator size by miniaturization is the availability of a sorbent material which provides high enough concentration factor. Single-walled carbon nanotubes (SWNTs) are promising materials for high adsorption capacity. In this report, a gas preconcentrator having the depth of 40 μm and the volume of 1 μL was microfabricated. The synthesized SWNT film with a thickness of 30 μm was embedded in the micro gas preconcentrator by using the hot water-assisted detachment method. The small size of the fabricated micro gas preconcentrator and the use of SWNTs as the adsorbent material allow for achieving a concentration factor as high as 16000 for 2 ppm octane. This value is the highest of micro gas preconcentrators, reported to date, and sufficient for micro-GC detectors to concentrate trace analytes of interest for breath analysis. It is demonstrated that the micro gas preconcentrators using SWNTs as an adsorbent material have great potential to concentrate compounds.

CNT Foam-Embedded Micro Gas Preconcentrator for Low-Concentration Ethane Measurements

“…Numerous studies have been conducted with the aim of improving the sensitivities and detection limits of gas sensors using gas preconcentration, which adsorbs low-concentration, gas-phase chemicals within a specified time interval and then desorbs these using heaters within a very short time interval. Several gas preconcentration and desorption apparatuses, known as thermal desorption (TD) systems, have already been developed [ 27 , 28 , 29 , 30 , 31 , 32 ]. However, the existing TD systems are large, expensive instruments that consume a lot of power and require intensive maintenance [ 33 ].…”

Mini pretreatment system integrated with micro pre-concentrator and micro GC column

“…With the development of the micro-electromechanical system (MEMS) technology, micro preconcentrators with small thermal mass were able to raise temperature much faster at lower power compared with conventional pre-concentrators, realizing a higher concentration factor. In recent years, many research teams were working on the chips (Michael et al, 2007;Voicolescu et al, 2006;Manginell et al, 2000;Alfeeli et al, 2011;Takada, 2010;Tian et al, 2003) and developed a number of micro pre-concentrators, which were able to easily integrate into hand-held and portable instruments for monitoring environmental samples. Voicolescu et al (2006) developed a micro pre-concentrator which can be successfully integrated into a hand-held chemical warfare agent analyzer.…”