A simple and fast procedure for in situ determination of water in ethanol fuel

Journal of the Brazilian Chemical Society

Angnes, Lúcio¹  Rocha, Fábio R. P.¹  Universidade de São Paulo, Piracicaba, Brazil¹  Ribeiro, Mauricio S.¹  Universidade de São Paulo, São Paulo, Brazil¹ 

关键词: ethanol fuel;    water;    in situ analysis;    conductivity;   

DOI  :  10.5935/0103-5053.20130054

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

A simple and inexpensive procedure, based on the high difference in solubility of sodium chloride in ethanol and water, is proposed to estimate the water content in ethanol fuel. The ionic concentration of solutions saturated with the salt is monitored by conductometric measurements with a linear response up to 16% water in an alcoholic medium and a limit of detection of 0.05% (v/v). The procedure is precise (coefficient of variation of 0.6%, n = 10) and accurate (results in agreement with those obtained by Karl Fischer amperometric titration at the 95% confidence level). An indicating electronic device exploiting the same principle was proposed for in situ monitoring of ethanol fuel samples aiming at the fast detection of unconformities. The device can be operated by nonexperts, generating a binary response indicated by coloured LEDs, and it successfully classified commercial samples spiked with different amounts of water.

【 授权许可】

Unknown