College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070, China.
College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070, China.
Anal Chim Acta. 2020 Sep 22;1131:25-34. doi: 10.1016/j.aca.2020.07.050. Epub 2020 Jul 30.
The sample introduction system of early miniaturized liquid cathode glow discharge (LCGD) was improved, and then LCGD was used as an excitation source of atomic emission spectrometry (AES) for the detection of mercury in water samples. The effects of chemical modifiers, such as ionic surfactants and low molecular weight organic substances, on emission intensities of Hg were investigated. The results showed that the addition of 4% methanol and 0.15% hexadecyltrimethylammonium bromide (CTAB) can enhance the net intensity of Hg about 15.5-fold and 7.7-fold, and the sensitivity (S) of Hg about 15.2-fold and 5.6-fold, respectively. Adding chemical modifiers markedly reduce the interferences from Fe, Co, Cl, Br, and I ions. The limit of detection (LOD) is reduced from 0.35 mg L for no chemical modifier to 0.03 mg L for 4% methanol and 0.05 mg L for 0.15% CTAB. The relative standard deviation (RSD) of Hg with adding 4% methanol, 0.15% CTAB and no chemical modifier is 2.38%, 1.17% and 3.00%, respectively, and the power consumption is below 75 W. All results indicated that the determination of Hg using improved LCGD with the addition of chemical modifiers has high sensitivity, low LOD, well precision and low power consumption. Water samples containing high mercury (10-20 mg L) and low mercury (0.2-5 mg L) can be determined by improved LCGD-AES with no chemical modifier and 4% methanol, respectively. Adding 4% methanol significantly reduces the matrix effects from real water samples. The measurement results of spiked samples using LCGD-AES are largely consistent with the spiked value. In addition, the recoveries of Hg are ranged from 95.7% to 114.8%, suggesting that the measurement results of Hg by LCGD-AES are accurate and reliable. Overall, the improved LCGD-AES with adding chemical modifiers is a promising technique for on-site and real-time monitoring of Hg in water samples because of its portability, lower cost and speed.
改进了早期微型化液体阴极辉光放电 (LCGD) 的样品引入系统，然后将 LCGD 用作原子发射光谱法 (AES) 的激发源，用于检测水样中的汞。研究了化学修饰剂（如离子表面活性剂和低分子量有机物质）对 Hg 发射强度的影响。结果表明，添加 4%甲醇和 0.15%十六烷基三甲基溴化铵 (CTAB) 可分别将 Hg 的净强度提高约 15.5 倍和 7.7 倍，将 Hg 的灵敏度 (S) 提高约 15.2 倍和 5.6 倍。添加化学修饰剂可显著降低 Fe、Co、Cl、Br 和 I 离子的干扰。无化学修饰剂时的检出限 (LOD) 从 0.35mg/L 降低到添加 4%甲醇时的 0.03mg/L 和添加 0.15%CTAB 时的 0.05mg/L。添加 4%甲醇、0.15%CTAB 和无化学修饰剂时 Hg 的相对标准偏差 (RSD) 分别为 2.38%、1.17%和 3.00%，功耗均低于 75W。所有结果表明，使用改进的 LCGD 并添加化学修饰剂测定 Hg 具有灵敏度高、LOD 低、精密度好、功耗低等特点。含有高浓度汞（10-20mg/L）和低浓度汞（0.2-5mg/L）的水样分别可以使用改进的 LCGD-AES 进行测定，无需添加化学修饰剂或添加 4%甲醇。添加 4%甲醇可显著降低实际水样的基质效应。使用 LCGD-AES 测定加标样品的测量结果与加标值基本一致。此外，Hg 的回收率在 95.7%至 114.8%之间，表明 LCGD-AES 测定 Hg 的测量结果准确可靠。总体而言，由于其便携性、低成本和快速性，添加化学修饰剂的改进型 LCGD-AES 是一种很有前途的现场实时监测水样中 Hg 的技术。
