A new system for the spectrophotometric determination of trace amounts of nitrite in environmental samples

Journal of the Brazilian Chemical Society

Tom Cherian¹  Badiadka Narayana¹ 

[1] ,Mangalore University Department of Post Graduate Studies and Research in Chemistry Mangalagangothri,India

关键词: spectrophotometry;    diazotization;    nitrite;    p-nitroaniline;    ethoxyethylenemaleic ester;    ethylcyanoacetate;   

DOI  :  10.1590/S0103-50532006000300022

来源: SciELO

【 摘 要 】

A selective and rapid spectrophotometric method for the determination of nitrite is presented. It is based on the reaction of nitrite with p-nitroaniline in acid medium to form diazonium ion, which is coupled with ethoxyethylenemaleic ester or ethylcyanoacetate in basic medium to form azo dyes, showing absorption maxima at 439 and 465 nm respectively. The method obeys Beer's law in the concentration range of 0.5-16 µg mL-1 of nitrite with ethoxyethylenemaleic ester and 0.2-18 µg mL-1 of nitrite with ethylcyanoacetate. The molar absorptivity and Sandell's sensitivity of p-nitroaniline-ethoxyethylenemaleic ester and p-nitroaniline-ethylcyanoacetate azo dyes are 5.04 X 10(4) L mol-1cm-1, 0.98 X 10-2 µg cm-2 and 1.21 X 10(4) L mol-1 cm-1, 0.98 X 10-2 µg cm-2 respectively. The optimum reaction conditions and other analytical parameters were evaluated. The method was successfully applied to the determination of nitrite in various water samples and soil samples.

【 授权许可】

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