This paper describes an automated persulfate oxidation method for the simultaneous determination of total dissolved nitrogen (TDN) and total dissolved phosphorus (TDP) in seawater using a gas-segmented continuous flow analyzer. Automation of simultaneous oxidation and colorimetric determination of TDN and TDP was performed by installing a heating oil bath unit with a long Teflon tube and an air compressor on the analyzer. Blank selection using single and mixed salt solutions dissolving sodium chloride, sodium sulfate, potassium bromide, and/or sodium hydrogen carbonate in pure water indicated that the single sodium chloride solution was most appropriate. The recoveries of various N and P compounds varied from 101% to 108% and 86% to 100%, respectively. Calibration curves showed suitable linearity ranges of 0–80 μM for the TDN analysis and 0–8 μM for the TDP analysis (r² = 1.00). The detection limits for TDN and TDP analyses were 0.17 and 0.04 μM, respectively. A throughput of 17 samples per hour was achieved. Application to oceanic water samples showed that TDN and TDP concentrations in the upper 300 m varied from 3.8 μM to 11.0 μM and 0.08 μM to 0.41 μM, respectively, with the coefficients of variation of <7%. These concentrations were not significantly different from those obtained from conventional methods. This proposed method has simple, fast, and economical characteristics and is suitable for simultaneous analyses of TDN and TDP, which help our understanding of N and P dynamics in the ocean.

本文介绍了一种自动过硫酸盐氧化方法，该方法使用气体分段连续流分析仪同时测定海水中的总溶解氮（TDN）和总溶解磷（TDP）。通过在分析仪上安装带有长铁氟龙管的加热油浴装置和空气压缩机，可以同时进行TDN和TDP的氧化和比色测定的自动化。使用将氯化钠，硫酸钠，溴化钾和/或碳酸氢钠溶解在纯水中的单一和混合盐溶液进行空白选择，表明单一氯化钠溶液最为合适。各种N和P化合物的回收率分别为101％至108％和86％至100％。r ²  = 1.00）。TDN和TDP分析的检出限分别为0.17和0.04μM。每小时可处理17个样品。在海洋水样中的应用表明，上部300 m中的TDN和TDP浓度分别在3.8μM至11.0μM和0.08μM至0.41μM之间变化，变异系数<7％。这些浓度与从常规方法获得的浓度没有显着差异。该方法具有简单，快速，经济的特点，适合同时分析TDN和TDP，有助于我们理解海洋中的N和P动力学。