Exploiting gas diffusion for non-invasive sampling in flow analysis: determination of ethanol in alcoholic beverages.
A tubular gas diffusion PTFE membrane is exploited for non-invasive sampling in flow analysis, aiming to develop an improved spectrophotometric determination of ethanol in alcoholic beverages. The probe is immersed into the sample, allowing ethanol to diffuse through the membrane. It is collected into the acceptor stream (acidic dichromate solution), leading to formation of Cr(III), monitored at 600 nm. The analytical curve is linear up to 50% (v/v) ethanol, baseline drift is < 0.005 absorbance during four working-hours, and sample throughput is 30 h(-1), meaning 0.6 mmol K2Cr2O7 per determination. Results are precise (r.s.d.< 2%) and in agreement with an official procedure.
Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, 13416-000 Piracicaba, SP, Brazil.
Simone
S
Vicente
Elias A G
EA
Zagatto
Paula C A G
PC
Pinto
Maria Lucia M E S
ML
Saraiva
José L F C
JL
Lima
Eduardo P
EP
Borges
D000434:Alcoholic Beverages / Q000032:analysis*; D002849:Chromatography, Gas / Q000295:instrumentation*; D004058:Diffusion; D000431:Ethanol / Q000032:analysis*; D005240:Feasibility Studies; D013053:Spectrophotometry
D000431:Ethanol