Comparison Experiment of UV Spectrophotometric Method and Flow Injection Analysis for Determination of Total Nitrogen in Water Samples
This article focuses on the determination of total nitrogen in practical water samples,and evaluates the reliability of applying the flow injection analysis method to replace the UV spectrophotometric method in the laboratory.Specifically,two experiments are designed to achieve this gold:the quality control experiment and the comparison experiment of the two methods.For quality control experiments,the determination results of total nitrogen meet the quality control requirements of the standards:curve correlation coefficient R≥0.999;calculated detection limit and calculated lower limit of determination show a lower value than that in related standards;blank experiments,RSD for parallel determinations,recovery rates,and the determination of certified reference materials all meet the requirements of the standards or certificates.For the method comparison experiment,two methods were used to measure total nitrogen in 22 groups of industrial wastewater,and the difference was evaluated by t test.The p value was 0.054(over 0.05),which proved that the results for total nitrogen determination were not different to some extent when using two methods.Therefore,it is reliable to use flow injection method to replace UV spectrophotometric method.In addition,this article discusses potential factors(reagent quality and purity,flow injection system,pH,metal ions and non-metal ions)that affect the determination of total nitrogen,and concludes that interference factors have little impact on the determination of total nitrogen in this experiment.
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