同时测定血清中4种电解质的流动注射微电极串联电化学自动分析系统

An Automatic Flow-injection Micro-electrode Electrochemical Analysis System for Simultaneous Determination of Four Kinds of Serum Electrolytes

基于流动注射-微电极串联的动态电化学技术,建立了能快速、自动、同时测定血清中K+,Na+,Cl-和Ca2+的分析方法和系统,并成功用于血清样品的测定。为稳定4种电极的基线电位、加快电极响应速度,优化了载流的组分:23 mmol/L Na2B4O7-H3BO3(pH 7.40),0.25 mmol/L K+,48.6 mmol/L Na+,2.5 mmol/LCl-和0.25 mmol/L Ca2+的混合液,流量为1.56 mL/min;混合盘管长度为30 cm(I.D.0.5 mm)。本方法的测定范围分别是2.0～22.0 mmol/L K+,90～253 mmol/L Na+,20～248 mmol/L Cl-,0.35～10.0 mmol/LCa2+,相对标准偏差小于1.05%(n=11),回收率为96.7%～103.7%,分析速度为120样/h,每次测定的样品耗量仅为45μL。本系统采用载流连续流动和微量样品注入,实现了系统的自动清洗,解决了样品交叉污染、流通式电极敏感膜表面血清纤维蛋白吸附及堵塞等问题,延长了使用寿命。

A new automatic analysis method and system for simultaneous determination of K ＋,Na ＋,Cl-and Ca2 ＋ in serum was proposed on the basis of flow-injection micro-electrode dynamic electrochemical technology （FI-ME-ECA）.To stabilize baseline potentials of four electrodes and to accelerate response of the electrodes, we have examined various components in the carrier of the FI-ME-ECA and optimized experimental conditions. Obtained results were as follows：23 mmol/L of Na2B4O7-H3BO3（pH 7.40） was used as the buffer solution, the carrier solution are consist of 0.25 mmol/L K ＋,48.6 mmol/L Na ＋,2.5 mmol/L Cl-and 0.25 mmol/L Ca2 ＋,and its flow rate is selected 1.56 mL/min.The length of mixing coil was 30 cm（I.D.0.5 mm）.The linear determination ranges of the method are 3.0-6.0 mmol/L for K ＋,90-253 mmol/L for Na ＋,20-248 mmol/L for Cl-and 0.35-10 mmol/L for Ca2 ＋,respectively,the relative standard deviation（RSD） is less than 1.1%（n = 11）,the recoveries obtained by adding K ＋,Na ＋,Cl-and Ca2 ＋ in serum samples are in range of 96.7%-103.7%,analysis speed of the system is 120 samples/h（480 detections/h）,consumption of the sample is only 45 μL at a time.Main merits of the FI-ME-ECA are injection of micro-volume sample and continuous flow of the carrier solution.It has achieved automatic cleaning of the FIA manifold,and has avoided carryover between the samples,and has removed sorption and stemming of fibrin on the sensor channels,and has prolonged life of the electrodes.