基于纸芯片的离子选择性电极系统检测海水中钙离子

A paper-based ion-selective electrode system for determination of Ca^(2+) in seawater

以滤纸为基底材料,通过滴涂导电碳浆及Ag/Ag Cl浆,分别制备了固态聚合物膜钙离子选择性指示电极和固态聚合物膜参比电极,构建了纸芯片离子选择性电极系统,用以检测海水中Ca^(2+)。实验中,优化了离子载体含量与离子选择性敏感膜厚度,考察了参比电极的稳定性及指示电极的选择性。结果表明,在0.5 mol/L NaCl背景下,该系统在1.0×10-4~3×10-2mol/L范围内呈现线性响应,响应斜率为24.3 m V/dec。将纸芯片电极用于实际海水样品中Ca^(2+)含量的测定,所得结果与电感耦合等离子体-原子发射光谱法检测数据一致。

A paper-based ion-selective electrode system for determination of Ca^2＋in seawater was described in the paper. The electrode system was constructed on a paper chip,composed of an allsolid-state polymeric membrane indicator electrode consisting of conductive carbon inks coated by a Ca^2＋-selective membrane and an all-solid-state reference electrode consisting of Ag/Ag Cl inks coated by a lipophilic salt-incorporating polymeric membrane. The content of ionophore and the thickness of the ion-selective membrane were optimized,and the stability of the reference electrode and the selectivity of the electrode were investigated. The results indicated that the electrode system showed a stable potential response with a slope of 24. 3 m V/dec in the linear range from 1. 0 × 10^-4 to 3 ×10^-2 mol/L under the background solution of 0. 5 mol/L Na Cl. The practical application of the proposed sensor system was carried out for detection of Ca^2＋in seawater samples,and the results agreed with those by inductively coupled plasma-atomic emission spectrometry.