| 摘要: |
| 在线消解海水测定溶解态总氮生成活性氯,引发气泡隔断异常和不稳定的现象,导致监测数据准确度和稳定性欠佳。通过优化消解试剂配方、采用气瓶在线控压注入气泡分隔液流、利用串联镉圈装置去除盐度干扰的技术建立一种自动测定海水中溶解态总氮的方法,在0~2.00 mg/L范围内具有较好线性关系,检出限为0.010 mg/L,平行样相对标准偏差为5.1%~7.0%,加标试验回收率为93.0%~101%,实样测定结果与HY/T 147.1—2013[1]相比,相对偏差为0.33%~3.7%。研究显示在线控压消解-串联镉圈去盐法抗干扰能力强,气泡分隔液流片段一致性好,使得仪器状态稳定性好和持续监测能力增强,根据质量控制标准其性能指标精密度、正确度和实样结果比对符合要求,检出限低于现有标准。 |
| 关键词: 串联镉圈 控压消解 气泡间隔 溶解态总氮 |
| DOI：10.11759/hykx20250122002 |
| 分类号:O657.32 |
| 基金项目:2024 年度中山市第一批社会公益与基础研究项目(2024B2027) |
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| Determination of total dissolved nitrogen in seawater by online controlled pressure digestion and serial cadmium ring desalting |
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QIU Zhenwu
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Guangdong Zhongshan Ecological Environment Monitoring Station, Zhongshan 528400, China
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| Abstract: |
| The measurement of dissolved total nitrogen in seawater by online digestion produces active chlorine, which causes abnormal bubble partition and instability, resulting in poor accuracy and stability of the monitoring data. This study established an automatic method for determining the total dissolved nitrogen in seawater by optimizing the digestion reagent formulation. This was achieved by applying online controlled pressure injection from a gas cylinder to separate the liquid flow and using a serial cadmium ring device to remove salinity interference. The method has a good linear relationship in 0–2.00 mg/L, and its detection limit is 0.010 mg/L. The standard deviation of the parallel sample is 5.1%–7.0%, and the spike recovery rate is 93.0%–101%. The relative deviation of the actual sample determination results compared with HY/T 147.1-2013 was 0.33% to 3.7%. Results show that the online controlled pressure digestion and serial cadmium ring desalting method has the following advantages: strong anti-interference ability, good consistency of bubble separator flow fragments, good state stability of the instrument, and enhanced and continuous monitoring ability. According to quality control standards, the method’s precision and accuracy, as well as measurement results for actual sample results, meet the specified requirements. Further, the detection limit is lower than that of the existing standards. |
| Key words: series cadmium ring controlled pressure digestion bubble spacing total dissolved nitrogen |
