Determination of Total Phosphorus and Nitrogen in Water by Ion Chromatography

Abstract

An ion chromatography combined with ultraviolet-ozone oxidation procedure was proposed for detecting total phosphorus(TP) and total nitrogen(TN) simultaneously in water samples.The mixed solution of Na2CO3/NaHCO3 was used as eluent,and the samples were injected with 1 mL large volume loop directly.Under the optimal conditions,TP concentration displays linear relationship in the range of 0.05-5.00 mg/L and TN concentration in the range of 0.10-10.00 mg/L.The correlation coefficient of curve was 0.9999 and 0.9998 respectively.The detection limit of TP was 3.60 μg/L and that of TN was 4.57 μg/L.The relative standard deviations(RSD) of TP and TN were less than 4.9 and 4.1% respectively.The standard addition recoveries of TP were from 95.0% to 105.0%,and those of TN were from 93.0% to103.0%.The relative error for the analysis of natural water samples to the standard were less than 4.2%.The method proposed has good selectivity and high sensitivity,as well as precision.The determination results agree well with those obtained by the National standard method.