基于长光程技术的痕量海水营养盐自动分析仪的设计与测试

海水中可溶性的营养盐浓度是海洋监测的常规项目之一；大洋水体中的营养盐含量很低，使用传统的分光光度计难于定量测量。文章基于液芯波导长光程技术，设计了高灵敏度的痕量海水营养盐光谱分析仪。分析仪以1.02 nm的光谱分辨率实现350～900 nm光谱范围的水样吸光度连续光谱测量，并由嵌入式PC104微机自动实现了水样采集、吸光度测量和数据分析的功能。针对亚硝酸盐的测试实验结果表明，仪器检出限达到nmol·L-1的量级，比传统分光光度计的检测限提高了三个量级，且显色反应时间可缩短到3 min，能适用于大洋水体中营养盐的现场痕量分析。

Construction and Test of Long Pathlength Automated Analyzer of Trace Nutrients in Seawater

Nutrients are routine aspects for marine environment monitoring. With low concentration in oceans, nutrients are difficult to be measured with a routine spectrophotometer. Based on liquid core waveguides, a new high-sensitivity analyzer was constructed to measure trace nutrients in oceans. The analyzer can provide continuous measurement of spectral absorbance of water sample in the spectral range from 350 to 900 nm with a spectral resolution of 1.02 nm. The processes such as sample injection, data acquisition of absorbance and data analysis are automatically controlled by a built-in PC104 micro computer. The results of test proved that, with the reaction time of about three minutes, the analyzer could provide a detection limit of the order of nmol·L-1, which is about 1 000 times lower than that of routine spectrophotometer. The analyzer is amenable to trace nutrients monitoring in oceans.