Exploiting gas diffusion for non-invasive sampling in flow analysis: determination of ethanol in alcoholic beverages

Anais da Academia Brasileira de Ciências

Simone Vicente¹  Elias A.g. Zagatto¹  Paula C.a.g. Pinto¹  Maria Lucia M.e.s. Saraiva¹  José L.f.c. Lima¹  Eduardo P. Borges¹ 

[1] ,Universidade de São Paulo Centro de Energia Nuclear na Agricultura Piracicaba SP ,Brasil

关键词: Flow-injection analysis;    ethanol determination;    gas diffusion;    semi-permeable membrane;    UVVis spectrophotometry;    análises por injeção em fluxo;    determinação de etanol;    difusão gasosa;    membrana semi-permeável;    espectrofotometria no UV-vis;   

DOI  :  10.1590/S0001-37652006000100004

来源: SciELO

【 摘 要 】

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.

【 授权许可】

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