Analysis for aqueous nitrates and nitrites and gaseous oxides of nitrogen by electron capture gas chromatography.

A highly sensitive gas chromatographic method is presented for the determination of aqueous nitrates. By suitable chemical pretreatment, this method is also applicable to the analysis of aqueous nitrites and gaseous oxides of nitrogen. The method has been applied to the analysis of drinking water, urine, and nitric acid. The technique involves the conversion of the nitrate ion to nitrobenzene with subsequent analysis by electron capture gas chromatography. The detection limit for nitrobenzene is ca. 10(-12) g, making possible the analysis of environmentally significant concentrations of aqueous nitrates and nitrites and gaseous oxides of nitrogen.