An automatic flow injection analysis procedure for photometric determination of ethanol in red wine without using a chromogenic reagent.
An automatic reagentless photometric procedure for the determination of ethanol in red wine is described. The procedure was based on a falling drop system that was implemented by employing a flow injection analysis manifold. The detection system comprised an infrared LED and a phototransistor. The experimental arrangement was designed to ensure that the wine drop grew between these devices, thus causing a decrease in the intensity of the radiation beam coming from the LED. Since ethanol content affected the size of the wine drop this feature was exploited to develop an analytical procedure for the photometric determination of ethanol in red wine without using a chromogenic reagent. In an attempt to prove the usefulness of the proposed procedure, a set of red wines were analysed. No significant difference between our results and those obtained with a reference method was observed at the 95% confidence level. Other advantages of our method were a linear response ranging from 0.17 up to 5.14 mol L(-1) (1.0 up to 30.0%) ethanol (R = 0.999); a limit of detection of 0.05 mol L(-1) (0.3%) ethanol; a relative standard deviation of 2.5% (n = 10) using typical wine sample containing 2.14 mol L(-1) (12.5%) ethanol; and a sampling rate of 50 determinations per hour.
Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Avenida Centenário 303, Piracicaba, CEP 13400-970 SP, Brazil.
Sivanildo S
SS
Borges
Rejane M
RM
Frizzarin
Boaventura F
BF
Reis
D001331:Automation; D002863:Chromogenic Compounds; D000431:Ethanol / Q000032:analysis*; D017022:Flow Injection Analysis / Q000379:methods*; D010783:Photometry / Q000379:methods*; D014920:Wine / Q000032:analysis*
D002863:Chromogenic Compounds; D000431:Ethanol