Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, 76019-0065, United States.
School of Environmental Studies, China University of Geosciences, Wuhan, 430078, Hubei, China.
Anal Chem. 2020 Apr 7;92(7):5561-5568. doi: 10.1021/acs.analchem.0c00505. Epub 2020 Mar 18.
A gas-free KOH eluent generator (EG) with 210 nL of internal volume is described. It utilizes a two-membrane configuration where there is a single CEM layer on one side and a single BPM layer on the other side for use in open tubular ion chromatography systems with typical back pressures < 50 psi. At a flow rate of ∼190 nL/min, the 10-90% gradient rise time is 3.5 min. The device shows good linearity between applied current and concentration of KOH generated, which is stable over extended periods. The overall system reproducibility (that includes contributions from any changes in flow rate), as judged by the relative standard deviation (RSD) of the retention times of individual separated ions in repeat measurements ( = 6), ranged from <0.5% for isocratic to <1.2% for gradient elution schemes. Perceptible current flow and KOH production in the BPM-based EG begins at subelectrolytic applied voltages, prompting us to look more closely at exact field strength necessary for field-enhanced dissociation of water. An increase in the specific conductance of pure water is noticeable by a field strength of 10 V/m.
一种无气 KOH 洗脱液发生器（EG），其内部体积为 210nL。它采用了一种双膜结构，一侧有一层 CEM 层，另一侧有一层 BPM 层，用于带有典型背压<50psi 的开管离子色谱系统。在流速约为 190nL/min 的情况下，10-90%的梯度上升时间为 3.5 分钟。该设备在施加电流和生成的 KOH 浓度之间表现出良好的线性关系，并且在长时间内保持稳定。通过在重复测量中（=6）单个分离离子的保留时间的相对标准偏差（RSD）来判断整个系统的重现性（包括流速变化的影响），从等度洗脱方案的<0.5%到梯度洗脱方案的<1.2%。在基于 BPM 的 EG 中，可察觉的电流流动和 KOH 生产始于亚电解施加电压，这促使我们更仔细地研究增强水离解所需的确切场强。通过 10V/m 的场强可以明显提高纯水的电导率。
