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.
Hydrotreating of petroleum deasphalted oils from thermal cracking residue and of a benzene-soluble fraction from SRC. Hydrocracking behavior of the asphaltene and polar compound fractions.
