Flow-injection biamperometry for direct determination of hydroxylamine at two pretreated platinum electrodes

Flow-injection biamperometry is used for the direct determination of hydrox ylamine based on coupling two independent and irreversible electrode proces ses, the oxidation of hydroxylamine and the reduction of platinum oxide. In operation a potential difference of 0 V is imposed between two platinum wi re electrodes pretreated by an anodization step. and the resulting current is measured. Hydroxylamine can be determined in the range of 6 x 10(-7) to 4 x 10(-5) mol l(-1) with the detection limit of 1 x 10(-7) mol l(-1). Nitr ogen-containing compounds such as nitrate, nitrite and ammonia that often a ccompany hydroxylamine in the process of nitrogen cycle do not cause signif icant interference. The stability of the detector is shown by a relative st andard deviation (R.S.D.) of 1.4% for 50 replicate determinations of 1 x 10 -5 mol l(-1) hydroxylamine. (C) 2001 Elsevier Science B.V. All rights reser ved.