Flow injection analysis for simultaneous determination of nitrogen and phosphorus in water samples

A continuous flow analyzer method was developed for the simultaneous determination of nitrogen and phosphorus in water samples,including ammonium nitrogen,nitrite,nitrate,total nitrogen,phosphate and total phosphorus. By integrating of a large auto sampler and two continuous flow analyzers and using mixed standard solutions for determination,the required amount of samples were reduced,and the simultaneous determination of the six indicators was also ensured. Measurement results of environmental reference materials were consistent with their certified values and uncertainty. Recoveries and relative standard deviations at five levels for spiked actual samples were 96. 3% ~ 107. 6% and 0. 54% ~ 2. 9%,respectively. This method could be widely applied to the rapid analysis of nitrogen and phosphorus concentrations in large amounts of water samples in the field of environmental monitoring,especially for small volume of water sample.