Anal Chem. 2010 Mar 1;82(5):1612-5. doi: 10.1021/ac902836e.
The first fully reversible polymeric membrane-based sensor for the anticoagulant heparin and other polyanions using a pulsed chronopotentiometry (pulstrode) measurement mode is reported. Polymeric membranes containing a lipophilic inert salt of the form R(+)R(-) (where R(+) and R(-) are tridodecylmethylammonium (TDMA(+)) and dinonylnaphthalene sulfonate (DNNS(-)), respectively) are used to suppress unwanted spontaneous ion extractions under zero-current equilibrium conditions. An anodic galvanostatic current pulse applied across the membrane perturbs the equilibrium lipophilic ion distribution within the membrane phase in such a way that anions/polyanions are extracted into the membrane from the sample. The membrane is then subjected to an open-circuit zero current state for a short period, and finally a 0 V vs reference electrode potentiostatic pulse is applied to restore the membrane to its initial full equilibrium condition. Potentials are sampled as average values during the last 10% of the 0.5 s open circuit phase of the measurement cycle. Fully reversible and reproducible electromotive force (emf) responses are observed for heparin, pentosan polysulfate (PPS), chondroitin sulfate (CS), and oversulfated chondroitin sulfate (OSCS), with the magnitude of the potentiometric response proportional to charge density of the polyanions. The sensor provides an emf response related to heparin concentrations in the range of 1-20 U/mL. The responses to variations in heparin levels and toward other polyanions of the pulstrode configuration are analogous to the already established single-use, nonreversible potentiometric polyion sensors based on membranes doped only with the lipophilic anion exchanger TDMA(+).
本文报道了首例基于全可还原聚合膜的、用于检测抗凝剂肝素及其他聚阴离子的传感器，该传感器采用脉冲计时电位法（pulstrode）测量模式。聚合膜中含有形式为 R(+)R(-) 的亲脂性惰性盐（其中 R(+) 和 R(-) 分别为三（十二烷基）甲基铵（TDMA(+))和二壬基萘磺酸根（DNNS(-))），以抑制在零电流平衡条件下的非必要自发离子萃取。在膜的两侧施加一个阳极恒电流脉冲，在这种方式下，脂溶性离子在膜相中平衡分布被打破，阴离子/聚阴离子从样品中被萃取到膜内。随后，膜会在短时间内处于开路零电流状态，最后施加一个 0V 相对于参比电极的恒电位脉冲，以将膜恢复到初始的完全平衡状态。在测量周期的最后 10%的开路阶段，对电位进行采样作为平均值。对于肝素、戊聚糖多硫酸酯（PPS）、硫酸软骨素（CS）和过硫酸化硫酸软骨素（OSCS），可以观察到完全可逆和重现的电动势（emf）响应，其电势响应的幅度与聚阴离子的电荷密度成正比。该传感器可提供与肝素浓度在 1-20U/mL 范围内相关的 emf 响应。针对肝素水平变化和其他聚阴离子的pulstrode 配置的响应类似于已建立的、基于仅掺杂亲脂性阴离子交换剂 TDMA(+)的一次性、不可逆的电势聚离子传感器。
