Low Cost Microstructures for Preconcentration of Polar and Non-Polar Organic Compounds
| Periodical | Materials Science Forum (Volumes 514 - 516) |
|---|---|
| Main Theme | Advanced Materials Forum III |
| Edited by | Paula Maria Vilarinho |
| Pages | 1250-1254 |
| DOI | 10.4028/www.scientific.net/MSF.514-516.1250 |
| Citation | Lilian Marques Silva et al., 2006, Materials Science Forum, 514-516, 1250 |
| Online since | May, 2006 |
| Authors | Lilian Marques Silva, Roberto R. Lima, Alexsander T. Carvalho, Maria Lucia Pereira Silva, Joana Catarina Madaleno, Luiz Pereira |
| Keywords | Plasma Thin Films, Preconcentrator, Sensor, VOC |
| Price | US$ 28,- |
Films produced by plasma polymerization of ethyl ether and methyl or ethyl acetate show good adsorption characteristic for polar and non-polar organic compounds. These films when used in microchannels machined in a 3D-structure present some preconcentration of organic compounds. Therefore, the aim of this work is to investigate the physical-chemical preconcentration mechanisms on this structure. The test molecules used were n-hexane and 2-propanol. Quartz crystal microbalance and mass spectrometry were used to measure preconcentration. Two different procedures for reactant injection on the structure were used: a continuous flow during several minutes or a small amount injected on a single pulse and in a few seconds. The microchannels were also modified by the introduction of small ceramic particles for enhancement of the flow dispersion. It was possible to notice for all films a similar kinetic of retention. The main removal mechanism is adsorption. Although all films can provide the removal of the adsorbents molecules, the most important characteristic for the adsorption and/or retention is the surface condition. Thus, the retention of polar compound can be troubled if a non-polar compound was used previously. The most promising films for retention are ethyl ether and ethyl acetate when n-hexane and 2-propanol are used as test molecules. The results using n-hexane or 2-propanol point out the use of low-cost microchannels for preconcentration development.
