[Study on colour reaction of iron(II)-thibarbituric acid-nitrite system and its analytical application].
In this paper, the optimum conditions of colour reaction of iron (II)-thibarbituric acid-NO2(-) system, existent state and spectrophotometric characteristies of the complex were studied, and the reaction mechanism discussed. A new spectrophotometric method for the determination of trace iron was established. In a buffer solution of borate/NaOH of pH9.5, iron (II) and thibarbituric acid-NO2(-) react to form a stable blue complex anion, for which the maximum absorbance is at 645nm and the molar absorptivity is 2.66 x 10(4)L x mol(-1) x cm(-1). Beer's law is obeyed in the range of 0-40 microg/25mL for iron (II). The method is simple and rapid, shows satisfactory selectivity and precision and has been applied to determine iron in waters with satisfactory results.
Huang
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Health and Antiepid Station, Xingshan County, 443700 Xingshan.