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

Abstract

Apresentamos um método espectrofotométrico seletivo e rápido para determinação de nitrito. O princípio do método é a reação do nitrito com p-nitroanilina, em meio ácido, formando o íon diazônio. O íon complexa com 2-etoxi maleato de dietila ou etilenoacetato, em meio básico, formando pigmentos tipo azo, com absorção máxima a 439 e 465 nm, respectivamente. O método obedece a lei de Beer no intervalo de 0,5-15 μg mL -1 para o nitrito com 2-etoxi maleato de dietila, e 0,2-12 μg mL -1 para o nitrito com etileno acetato. A absortividade molar e a sensitividade de Sandell encontradas para os respectivos pigmentos azo foram 5,04×104 L molForam avaliadas as condições ótimas de reação, bem como outros parâmetros analíticos. O método foi aplicado com sucesso na determinação de nitrito em várias amostras de água e solos.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. , 0.98×10 -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.

Colorimetric determination of nitrite in clinical, food and environmental samples using microfluidic devices stamped in paper platforms

“…The determination of nitrite is usually performed by conventional techniques including spectrophotometry 30,31 , amperometry 32 , chemiluminescence 33 and fluorescence 34 . Different authors have also used these detectors coupled with electrophoretic 35,36 or chromatographic 34,37 separation methods or flow injection analysis 38 .…”

Correlation of serum toll like receptor 9 and trace elements with lipid peroxidation in the patients of breast diseases

“…The total volume was made to 250 L and allowed to stand for 10 min at room temperature. The absorbance of the azo dye was measured at 490 nm against the reagent blank [17,18].…”

Clinical Significance and Analytical Determination of Trace Amounts of Selenium in Human Blood - Spectrophotometeric Technique~!2009-12-24~!2010-03-10~!2010-04-20~!

“…The total volume was made to 250μL and allowed to stand for 10 min at room temperature. The absorbance of the azo dye was measured at 490 nm against the reagent blank [1].…”

“…This method has been applied for the determination of trace amounts of selenium in plant material, polluted water and soil samples [1] and has been employed in the current work for human blood sera. …”