@@ 1引言rn硝酸盐广泛存在于各种环境水体中.当饮用水中硝酸盐浓度过高时,可能对人体健康造成危害;地表水中硝酸盐大量积累,则可能引起藻类过度繁殖,溶解氧耗竭,水质恶化.目前,检测硝酸盐的最常用方法是将硝酸盐还原为亚硝酸盐,再经重氮偶联反应后由分光光度法进行测定[1].此类方法已较好地与流动分析技术相结合,广泛应用于测定环境样品中硝酸盐[2～4].%An environmental friendly method was developed based on reversed flow injection (r-FIA) with UV-induced reduction of nitrate to nitrite and spectrophotometric detection. Sample or standard solutions were mixed with a phosphate buffer solution containing diethylenetriaminepentaacetate (DTPA), and then passed through a UV reduction reactor equipped with an 8 W low pressure mercury lamp, where the nitrate was reduced to nitrite. The formed nitrite was detected with spectrophotometric method through Griess reaction. Less than 20 μmol/L of nitrite showed no effect on the nitrate analysis. Reduction efficiency over 80％ was obtained. The detection limit of the proposed method was 0. 053 μmol/L and linear range was 0.2-40 μmol/L. A sample of 20 μmol/L nitrate was continually measured for 48 times, and a RSD of 2.22％ was obtained. The recoveries of drinking waters were between 90. 9 ％- 100.6 ％.
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