研制了基于气相可逆比色法的小型水样氨氮自动光学检测装置样机,该装置主要由样品室、测试室、自动进样模块和数据处理与控制电路组成。以不同浓度氯化铵水溶液作为氨氮样品测试了样机性能,建立了样机吸光度与氨氮浓度的线性依赖关系式;通过比较样机对氨氮标样的测试值和样品标准值,验证了样机的可靠性。研究结果表明,该样机能够在室温下对水样氨氮进行连续长时间的自动检测,具有较好的测试重复性,探测极限约为0.04 mg/L(以N计),低于国家标准对一类水的检测上限(0.15 mg/L,以N计)。该装置体积小,重量轻,成本低,功耗小,自动化程度高,无需对水样进行复杂预处理,适合水环境现场的快速检测。

A compact optical sensor for the automatic detection of ammonia nitrogen in water was developed based on a combination of liquid-gas separation and gas-phase reversible colorimetry. The sensor consists of a sample chamber, a test chamber, a program-controlled sampling unit and a data-processing circuit module. The sensor performance was investigated by using a series of aqueous ammonium chloride solutions with different concentrations as the ammonia nitrogen samples. The linear relationship between the measured absorbance and the ammonia-nitrogen concentration was obtained and the high reliability of sensor was demonstrated by comparing the measured and given concentrations of standard ammonia nitrogen samples. The experimental results indicate that the sensor works continuously and automatically for a long time at a room temperature and has good repeatability. The detection limit is 0.04 mg/L (NH3-N). The sensor is characterized by its smaller volume, light-weight, lower cost and power consumption, high-level automation, and it is suitable for on-site rapid detection of ammonia nitrogen in a practical water environment.