海水中氨氮的纳氏试剂分光光度法测定条件优化

Optimized conditions of Nessler's reagent spectrophotometry for ammonia nitrogen determination in seawater

采用纳氏试剂分光光度法,以试液吸光度和浊度作为参考,按照正交试验设计方法,优化了海水中氨氮测定过程中酒石酸钾钠、氢氧化钠及纳氏试剂用量.结果表明:纳氏试剂分光光度法测定海水中氨氮时,纳氏试剂的使用量是影响测定的主要因素.当试液的体积为10mL时,酒石酸钾钠(500g/L)、氢氧化钠(200g/L)和纳氏试剂的最佳用量分别为1.0,0.6,0.2mL,最佳显色时间为10min.通过对实际海水养殖过程中氨氮的测定,验证了优化的测定条件具有很强的实际操作性.

Using Nessler＇s reagent spectrophotometry as ammonia nitrogen determination method in seawater,selecting the absorbance and turbidity of test solutions as evaluation criteria,the amount of potassium sodium tartrate, sodium hydroxide and Nessler＇s reagent were optimized by orthogonal ex- periment design. The results show that the main factor affecting the determination is the used amount of Nessler＇s reagent. When the volume of test solutions is 10 mL,the optimum volume for potassium sodium tartrate（500 g/L）, sodium hydroxide （200 g/L）, and Nessler＇ s reagent are 1.0,0.6, and 0.2 mL, respectively. Meanwhile, the best color time for measurement is 10min. Based on the perform- ance of optimum conditions in ammonia nitrogen determination, this methodology display enormous operability in marine aquaculture.