title: Determination of ethanol in liquor by near-infrared spectrophotometry with flow injection.
abstract: A simple procedure for the determination of ethanol in a liquor by near-infrared (NIR) spectrophotometry with flow injection (FI) is proposed. A liquor sample is equilibrated off-line with dried chloroform to extract ethanol into the organic phase. The extract is injected into a carrier stream of dried chloroform passing through a home-made flow through cell (1 mm path length) sitting in a NIR spectrophotometer for continuous monitoring of absorbance at 2305 or 2636 nm. The ethanol content can be evaluated from a calibration established by a plot of change in absorbance versus concentration of ethanol standard solutions. Optimization of the system will be discussed. A calibration is linear in the range of 20-50% (v/v) ethanol. A throughput of 240 injections h(-1) can be obtained. The procedure is validated by comparing the results with an analysis using gas chromatography.
authors.affiliation: Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: P
authors.initials: P
authors.lastname: Tipparat
authors.forename: S
authors.initials: S
authors.lastname: Lapanantnoppakhun
authors.forename: J
authors.initials: J
authors.lastname: Jakmunee
authors.forename: K
authors.initials: K
authors.lastname: Grudpan