Two-stage microtrap as an injection device for continuous on-line gas chromatographic monitoring

Analytical challenges in breath analysis and its application to exposure monitoring

“…Sorbent traps present the advantages that they can be prepared on a micro-scale and coupled on-line with a GC system to allow near real-time measurements [97][98][99][100][101], and the sorbent configuration can be easily changed to adapt to different compounds.…”

“…However, the wide range of VOCs present in breath results in no single sorbent being capable of adsorbing all the compounds present in breath samples, so a multicomponent sorbent is necessary to complete screening and determination [25,44,64,[95][96][97]100,101].…”

Capillary thermal desorption unit for near real-time analysis of VOCs at sub-trace levels. Application to the analysis of environmental air contamination and breath samples

“…Second, the use of a cryotrap increases the complexity of the 10 instrumentation and makes it necessary to use cryogenic gases, which complicates the development of portable instruments based on this configuration. It has been demonstrated that it is possible to develop miniaturized TD modules without the use of cryogenic traps, which allow the direct injection of the retained VOCs in the multibed trap into a GC column [17,20,21]. When using this simplified configuration, the formation of artifacts due to thermal oxidation reactions in the surface of the sorbents is reduced and more reproducible results can be obtained [20].…”

“…Feng and Mitra [21] showed that the greater the internal diameter of the adsorbent microtrap, the greater the bandwidth of the desorbed compounds. However, the use of small-internal diameter traps has the disadvantage that there is an increase in the pressure drop along the trap, which decreases the sampling flow rate.…”

Uso de filmes obtido pela polimerização por plasma de tetraetilortossilicato na fabricação de dispositivos miniaturizados.

“…VOC's são normalmente analisados por cromatografia gasosa e podem fazer uso de pré-concentradores [39]. Sistemas pequenos de adsorção já foram reportados [40,41] e atualmente estão sendo miniaturizados [42]. Zellers et al [43] propôs a construção de um micro cromatógrafo (µCG) para a determinação de 30-50 tipos distintos de vapores, misturados em ppb (partes por bilhão) [44], e adsorção em esferas de grafite [45, 46, 47,].…”