Analytical Sciences

Abstract − Analytical Sciences, 34(2), 169 (2018).

A “Dual-acceptor Channel” Membraneless Gas-diffusion Unit for Simultaneous Determination of Ethanol and Acetaldehyde in Liquors Using Reverse Flow Injection
Nathawut CHOENGCHAN,*1,*2 Bangerdsuk POONTONG,*1,*2 Arjnarong MATHAWEESANSURN,*1,*2 Noppadol MANEERAT,*3 Shoji MOTOMIZU,*4 Nuanlaor RATANAWIMARNWONG,*1,*5 and Duangjai NACAPRICHA*1,*6
*1 Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs), Thailand
*2 Applied Analytical Chemistry Research Unit, Department of Chemistry, Faculty of Science, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand
*3 Department of Control Engineering, Faculty of Engineering, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand
*4 Okayama University Incubator, 109, 1-1-1 Tsushimanaka, Okayama 700-8530, Japan
*5 Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Bangkok 10110, Thailand
*6 Department of Chemistry and Center of Excellent for Innovation in Chemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
A new design of membraneless gas-diffusion unit with dual acceptor channels for separation, collection and simultaneous determination of two volatile analytes in liquid sample is presented. The unit is comprised of three parallel channels in a closed module. A sample is aspirated into the central channel and two kinds of reagents are introduced into the other two channels. Two analytes are isolated from the sample matrix by diffusion into head-space and absorbed into the specific reagents. Non-absorbed vapor is released by opening the programmable controlled lid. The unit was applied to liquors for measurement of ethanol and acetaldehyde using reverse flow injection. Dichromate and nitroprusside were exploited as reagents for colorimetric detection of ethanol and acetaldehyde, respectively. Good linearity ranges (r2 >0.99) with high precision (RSD <2%) and high accuracy (recovery: 90 – 105%) were achieved. The results were compared to the results by GC-FID and no significant difference was observed by paired t-test (95% confidence).