建立了同时快速、准确测定萝卜中K+、Ca2+、Na+和Cl-的流动注射异步注入-离子选择性电极法。最佳试验条件为:系统流量为2.43 mL·min-1;总离子强度调节缓冲液(TISAB)由80 mmol·L-1 Tris-硼酸(pH 6.00)、0.05 mmol·L-1 Na+、0.5 mmol·L-1 K+、0.01 mmol·L-1 Ca2+和0.57 mmol·L-1 Cl-组成;反应盘管长度为50 cm;采样体积为220 μL;混合标准溶液的pH为6.00。K+、Ca2+、Na+和Cl-的线性范围分别为10~70,0.5~7.0,10~36,21~119 mmol·L-1,检出限(3s/k)分别为5.0,0.2,5.0,10 mmol·L-1。加标回收率在92.8%~110%之间,测定值的相对标准偏差(n=11)小于2.0%。

A rapid and accurate method for simultaneous determination of K+, Ca2+, Na+ and Cl- in radish was established by using ion selective electrode coupled with flow-injection asynchronous injection. The optimum conditions were as follows: the flow rate was 2.43 mL·min-1; the total ion strength adjustment buffer consists of 80 mmol·L-1 of Tris-H3BO3 (pH 6.00), 0.05 mmol·L-1 of Na+, 0.5 mmol·L-1 of K+, 0.01 mmol·L-1 of Ca2+ and 0.57 mmol·L-1 of Cl-; the reaction coil length was 50 cm; the sampling volume was 220 μL; the pH of the mixed standard solution was 6.00. The linearity ranges of K+, Ca2+, Na+ and Cl- were 10-70, 0.5-7.0, 10-36, 21-119 mmol·L-1, respectively, with detection limits (3s/k) of 5.0, 0.2, 5.0, 10 mmol·L-1, respectively. Recovery rates obtained by standard addition method were in the range of 92.8%-110% and RSD (n=11) was less than 2.0%.