在线镉柱还原-流动注射法测定水样中硝酸盐氮实验

Experiment determining nitrate nitrogen in water samples by on-line cadmium column reduction-flow injection method

建立了在线镉柱还原测定水样中硝酸盐氮的流动注射光度法,并考察了反应管长度、注样体积、泵流量等实验条件对结果的影响。经过优化实验条件,获得该方法的线性范围为0~50 mg/L,相关系数r=0.999,检出限为0.034 mg/L,相对标准偏差为0.65%（n=11）。实验结果表明,该方法线性范围宽,试剂消耗量少、测定快速、灵敏,抗干扰能力强,实际水样的加标回收率均在98.8%~105.0%之内,适宜于现场即时监测。

A flow injection spectrophotometric method with an online cadmium column reduction technique for determination of nitrate nitrogen in a water sample was developed,and the influence of experimental conditions such as the length of the pipeline,the volume of the sample,and the flow rate of the pump on determined results was studied.After optimizing experimental conditions,nitrate nitrogen could be determined linearly within the range of 0-50 mg/L（correlation coefficient r=0.999）,the detection limit was 0.034 mg/L,and the relative standard deviation（RSD） value was 0.65%（n=11）.The results showed that the method had a wider linear range,consumed fewer reagents,and had the features of rapid determination,sensitivity,and higher anti-interference ability.The sample recovery rate was in the range of 98.8%-105.0% and the method is suitable for field measurement.