State Key Laboratory of Biogeology and Environmental Geology, Faculty of Earth Sciences, China University of Geosciences, Wuhan, China 430074.
Analyst. 2011 Nov 7;136(21):4539-44. doi: 10.1039/c1an15332c. Epub 2011 Sep 21.
This paper describes a low-temperature dielectric barrier discharge (DBD)-plasma induced vaporization technique using mercury as a model analyte. The evaporation and atomization of dissolved mercury species in the sample solution can be achieved rapidly in one step, allowing mercury to be directly detected by atomic fluorescence spectrometry. The DBD plasma was generated concentrically in-between two quartz tube (outer tube: i.d. 5 mm and o.d. 6 mm, inner tube: i.d. 2 mm and o.d. 3 mm). A copper electrode was embedded inside the inner quartz tube and sample solution was applied onto the outer surface of the inner tube. The effects of operating parameters such as plasma power, plasma gas identity, plasma gas flow rate and interferences from concomitant elements have been investigated. The difference in the sensitivities of Hg(2+), methylmercury (MeHg) and ethylmercury (EtHg) was found to be negligible in the presence of formic acid (≥1% v/v). The analytical performance of the present technique was evaluated under optimized conditions. The limits of detection were calculated to be 0.02 ng mL(-1) for Hg(2+), MeHg and EtHg, and repeatability was 6.2%, 4.9% and 4.3% RSD (n = 11) for 1 ng mL(-1) of Hg(2+), MeHg and EtHg, respectively. This provides a simple mercury detection method for small-volume samples with an absolute limit of detection at femtogram level. The accuracy of the system was verified by the determination of mercury in reference materials including freeze-dried urine ZK020-2, simulated water matrix reference material GBW(E) 080392 and tuna fish GBW10029, and the concentration of mercury determined by the present method agreed well with the reference values.
本文描述了一种使用汞作为模型分析物的低温介电阻挡放电（DBD）等离子体诱导蒸发技术。溶解在样品溶液中的汞物种可以在一步中迅速蒸发和原子化，从而可以直接通过原子荧光光谱法检测汞。DBD 等离子体在内、外两个石英管（外管：内径 5 毫米，外径 6 毫米；内管：内径 2 毫米，外径 3 毫米）之间同心产生。一个铜电极嵌入在内管内部，样品溶液施加在外管的内表面上。研究了等离子体功率、等离子体气体种类、等离子体气体流量等操作参数的影响以及共存元素的干扰。发现在存在甲酸（≥1%v/v）的情况下，Hg(2+)、甲基汞（MeHg）和乙基汞（EtHg）的灵敏度差异可以忽略不计。在优化条件下评估了本技术的分析性能。检测限计算为 0.02 ng mL(-1) Hg(2+)、MeHg 和 EtHg，对于 1 ng mL(-1) Hg(2+)、MeHg 和 EtHg，重复性分别为 6.2%、4.9%和 4.3%RSD（n = 11）。这为小体积样品提供了一种简单的汞检测方法，绝对检测限达到飞克级。通过对包括冷冻干燥尿液 ZK020-2、模拟水基质参考物质 GBW(E)080392 和金枪鱼鱼 GBW10029 在内的参考材料中汞的测定，验证了系统的准确性，本方法测定的汞浓度与参考值吻合良好。
