4631369753

OZNACZANIE AZOTANÓW(III), (V) I TLENKÓW AZOTU 1183

ABSTRACT

The paper presents a review of spectrophotometric methods for determination of nitrates (III), (V) and nitric oxides [1-48] with particular emphasis on the possi-bilities of the Griess-Ilosvay method. The original method [50, 51], developed for determination of nitrates (III) and based on derivatisation of these compounds to nitrogen dyes, has undergone many modifications over the decades. The aim of the modifications was to enhance the method’s sensitivity, decrease the level of determination, simplify the procedurę and its adjustment to achieve the most effective determination also in the presence of a complex matrix [52-67]. The increasing demands of analytical chemistry and the need to determine tracę or ultratrace amo-unts of nitrates have prompted further improvement of the Griess-Ilosvay method by combining it with methods of analyte enrichment such as liquid—liąuid extrac-tion [68-80] and liąuid—solid extraction [81-94], The recent need for routine deter-minations in the monitoring of the natural environment has led to the development of the fast flow-through - injection methods [95-127], making the analytical pro-cess morę effective and convenicnt to use. One of the most recent achievements in analytical chemistry of nitrates (III) and (V) has been the development of optical sensors (optrodes) [128-132], They are used in modified versions of the Griess-Ilosvay method and permit a direct and relatively easy determination of the contents of nitrates preserving a high sensitivity of the method. The paper gives a comparati-ve review of the modifications of the Griess-Uosvay method from the earliest to the most recent.