Yu Jie, Zhang Xiaomin, Lu Quanfang, Yin Ling, Feng Feifei, Luo Hui, Kang Yuejing
College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, China.
Editorial Department of the University Journal, Northwest Normal University, Lanzhou 730070, China.
ACS Omega. 2020 Jul 27;5(31):19541-19547. doi: 10.1021/acsomega.0c01906. eCollection 2020 Aug 11.
A liquid cathode glow discharge (LCGD) was developed as a low-power and miniaturized excitation source of atomic emission spectrometry (AES) for the determination of K, Na, Ca, and Mg in water samples from rivers and lakes. The discharge stability and parameter influencing the analytical performance of LCGD-AES were systematically examined. Moreover, the measurement results of water samples using LCGD-AES were verified by ion chromatography (IC). The results showed that the optimized operating parameters are a 660 V discharge voltage, pH = 1.0 HNO as the supporting electrolyte, and a 4.0 mL min solution flow rate. High concentrations of some metals may interfere with the detection of Ca and Mg. Low-molecular-weight organic substances do not have a remarkable enhancement on signal intensity. With the addition of 0.5% cetyltrimethylammonium chloride (CTAC), the emission intensity of elements can enhance significantly. However, it is not used to further evaluate the analytical performance due to instability of plasma after adding CTAC. The maximum power of LCGD is 52 W. The limits of detection and precision (RSD, in 1 mg L) of K, Na, Ca, and Mg are 0.20, 0.02, 0.01, and 0.01 mg L and 0.9, 1.5, 0.6, and 1.2%, respectively. The measurement results of K, Na, Ca, and Mg in water samples by LCGD-AES are basically in agreement with the reference values measured by IC. The recovery of samples ranged from 84 to 113% except for Na, suggesting that the measurement results have high accuracy and reliability. All the results indicated that the LCGD-AES can provide an alternative analytical method for in situ, real-time, on-line determination of K, Na, Ca, and Mg in water samples from rivers and lakes.
液态阴极辉光放电（LCGD）被开发为一种低功率且小型化的原子发射光谱法（AES）激发源，用于测定河流和湖泊水样中的钾、钠、钙和镁。系统地研究了放电稳定性以及影响LCGD-AES分析性能的参数。此外，使用离子色谱法（IC）对LCGD-AES测定水样的结果进行了验证。结果表明，优化的操作参数为660V放电电压、pH = 1.0的硝酸作为支持电解质以及4.0 mL/min的溶液流速。某些金属的高浓度可能会干扰钙和镁的检测。低分子量有机物质对信号强度没有显著增强作用。添加0.5%的十六烷基三甲基氯化铵（CTAC）后，元素的发射强度可显著增强。然而，由于添加CTAC后等离子体不稳定，未用于进一步评估分析性能。LCGD的最大功率为52W。钾、钠、钙和镁的检测限和精密度（RSD，1mg/L时）分别为0.20、0.02、0.01和0.01mg/L以及0.9%、1.5%、0.6%和1.2%。LCGD-AES测定水样中钾、钠、钙和镁的结果与IC测定的参考值基本一致。除钠外，样品回收率在84%至113%之间，表明测量结果具有较高的准确性和可靠性。所有结果表明，LCGD-AES可为现场、实时、在线测定河流和湖泊水样中的钾、钠、钙和镁提供一种替代分析方法。
