title: A negative-pressure flow-injection micro-electrode system for rapid and simultaneous determination of four electrolytes in human serums.
abstract: An automatic system for simultaneous determination of K(+), Na(+), Cl(-) and Ca(2+) in serums was established on the basis of a negative-pressure flow-injection using micro-electrodes, and parameters of the system were optimized. The total ionic strength adjustment buffer consisted of 0.25 mmol L(-1) K(+), 48.6 mmol L(-1) Na(+), 2.56 mmol L(-1) Cl(-), 0.25 mmol L(-1) Ca(2+) and 23 mmol L(-1) Na(2)B(4)O(7)-H(3)BO(3); the flow rate was 1.58 mL min(-1), the sampling volume was 45 µL, and the mixing coil length was 30 cm. The system could conduct 480 detections h(-1), and its RSD was less than 1.6%. Recoveries were 97.3 - 103.6%, and linear responses were 2.0 - 22.0 mmol L(-1) for K(+), 89.6 - 253.0 mmol L(-1) for Na(+), 20.1 - 248.2 mmol L(-1) for Cl(-), and 0.35 - 10.0 mmol L(-1) for Ca(2+), respectively. The ion concentration ranges were in ranges of human serum electrolytes. The system features minimized sorption of fibrin in sensors and prolonged sensor life.
authors.affiliation: School of Chemical Engineering, Sichuan University, Chengdu, PR China. lysgxf2005@yahoo.com.cn
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.forename: Hui-Sheng
authors.initials: HS
authors.lastname: Zhang
authors.forename: Zhen-Yao
authors.initials: ZY
authors.lastname: Lai
authors.forename: Xiu-Feng
authors.initials: XF
authors.lastname: Gao
mesh_terms: D002118:Calcium / Q000097:blood; D002712:Chlorides / Q000097:blood; D004573:Electrolytes / Q000097:blood*; D017022:Flow Injection Analysis / Q000295:instrumentation; D006801:Humans; D008839:Microelectrodes; D011188:Potassium / Q000097:blood; D011312:Pressure; D012964:Sodium / Q000097:blood; D013997:Time Factors
chemical_list: D002712:Chlorides; D004573:Electrolytes; D012964:Sodium; D011188:Potassium; D002118:Calcium