Zhou Yue, Sun Yue, Zhang Feifang, Yang Bingcheng
Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai, 200237, China.
Heliyon. 2021 Feb 10;7(2):e06229. doi: 10.1016/j.heliyon.2021.e06229. eCollection 2021 Feb.
We for the first time describe a gas-free electrodialytic pH modifier deployed at the pump outlet side to manipulate carbonate eluent used for ion chromatography (IC). It is in sandwich configured, in which the central eluent channel is spatially isolated from two outer regenerant chambers by a stacked cation exchange membranes (sCEM) and a bipolar membrane (BPM) plus a stacked anion exchange membranes (sAEM) (BPM-sAEM), the cation exchange side of BPM is facing the central channel (the cathode direction). One electrode is put in each regenerant chamber and the sCEM side is cathode with respect to the anode of BPM-sAEM side. When a potassium carbonate eluent is pumped into the central channel and a DC current is applied, a controlled amount of potassium ions will be removed by migrating across sCEM into cathodic chamber. Meanwhile, hydronium ions generated from enhanced water splitting at the intermediate layer of BPM will electromigrate into central channel to form bicarbonate. By controlling the current, the potassium carbonate eluent can be manipulated to obtain a mixed eluent with different ratio of carbonate and bicarbonate. At least 10 mM KCO eluent can be online changed modified into 10 mM KHCO with near-ideal Faradaic efficiency (∼92%). The device demonstrated good reproducibility, as indicated by retention time of relative standard deviation (RSD) < 0.43% and the peak area of RSD <0.93%.
我们首次描述了一种部署在泵出口侧的无气电渗析pH调节剂，用于操控离子色谱（IC）中使用的碳酸盐洗脱液。它采用三明治结构，其中中央洗脱液通道通过堆叠的阳离子交换膜（sCEM）、双极膜（BPM）和堆叠的阴离子交换膜（sAEM）（BPM-sAEM）与两个外部再生室在空间上隔离，BPM的阳离子交换侧朝向中央通道（阴极方向）。每个再生室中放置一个电极，sCEM侧相对于BPM-sAEM侧的阳极而言为阴极。当将碳酸钾洗脱液泵入中央通道并施加直流电流时，一定量的钾离子会通过sCEM迁移到阴极室而被去除。同时，在BPM中间层增强的水分解产生的水合氢离子将电迁移到中央通道形成碳酸氢盐。通过控制电流，可以操控碳酸钾洗脱液以获得具有不同碳酸盐和碳酸氢盐比例的混合洗脱液。至少10 mM的KCO洗脱液可以在线转变为10 mM的KHCO，法拉第效率接近理想值（约92%）。该装置具有良好的重现性，相对标准偏差（RSD）的保留时间<0.43%，峰面积的RSD<0.93%。
