流动注射串联电极法同时测定海水及地热水中的钾/钠/钙/氯离子

Simultaneous Determination of K^+/ Na^+/Ca^(2+)/Cl^-in Seawater and Geothermal Water with Flow-Injection Serial-Ion Selective Electrodes

随着对海水、地热水资源越来越多的开发利用,测定其中的K+、Na+、Ca2+、Cl-含量的需求也随之增加。研究建立了一种双管线流动注射串联离子选择电极自动方法(FI-ISE-S),能用于海水、地热水中K+、Na+、Ca2+、Cl-同时、快速、自动测定。在研究过程中,对FI-ISE-S系统的各种影响因素,如系统流量、进样体积、混合盘管长度、干扰物质、总离子强度调节缓冲液的酸度及离子浓度等进行了考察和优化。在最优条件下,得到的分析速度为100样h 1,每次测定的样品用量仅为160μL,相对标准偏差小于1.96%(n=11),标准添加回收率为91.9%~109.6%,测定范围分别为1.0~8.0 mmol L 1K+、50~290 mmol L 1Na+、3.2~16.0 mmol L-1Ca2+、70~430 mmol L -1Cl-。该方法已成功应用于实际海水及地热水样品的测定。

With more and more exploitation and utilization of seawater and geothermal water, the demand of determining the concentration of K~, Na~, Ca^（2＋） and Cl- in them has been increased. A method of flow-injection serial- ion selective electrodes （FI-ISE-S） for simultaneous and rapid determination of K＋, Na＋, Ca^（2＋） and Cl- in sea water and geothermal water was established. In the research, various influence factors of the FI-ISE-S system were investigated and optimized, including flow rate of system, sampling volume, the length of mixing coil, interfering substances, the acidity and ion concentration of the total ion strength adjusting buffer solution. Among the optimal conditions, the analysis speed of the system is 100 samples.h^（-1）; the consumption of the sample is only 160 p.L per time; the relative standard deviation （RSD） is less than 1.96% （n=11）; the recoveries obtained by adding K＋, Na＋, Ca^（2＋） and Cl- in the samples are in range of 91.9%-109.6%; and the linear determination ranges of the method are 1.0-8.0 mmol·L^（-1） for K＋, 50-290 mmol.L-l for Na＋. 3.2-16.0 mmol·L^（-1） for Ca^（2＋）, 70-430 mmol·L^（-1） for C-. It has been successfully applied in the determination of seawater and geothermal water.