抗坏血酸对等离子体质谱法测定汞的增敏作用研究

研究了将抗坏血酸加入到样品中作为增敏剂,以电感耦合等离子体质谱测定汞的增敏效应。考察了硝酸浓度、抗坏血酸浓度、水浴温度和时间等实验条件对增敏作用的影响。结果表明,在5%硝酸,500 mg·L~(-1)的抗坏血酸,水浴温度50℃,时间为20 min的条件下,汞的灵敏度最高,此时,汞的灵敏度增强近30倍,其检出限低至1 ng·L~(-1)。在汞浓度为0.005~10.0μg·L~(-1)范围内线性关系良好,相关系数为0.999,相对标准偏差为5.6%(0.1μg·L~(-1),n=7)。该文还进一步探讨了抗坏血酸产生增敏作用的机理。

Study on Ascorbic Acid Signal Enhancement for Hg Determined by Inductively Coupled Plasma Mass Spectrometry

In this study,ascorbic acid was added into the sample solution to improve the signal intensity of Hg determined by inductively coupled plasma mass spectrometry (ICP-MS).Factors effecting the signal enhancement,such as concentrations of nitric acid and ascorbic acid,temperature and time of water bath,were optimized.According to the results,5％ of HNO3,500 mg · L-1 of ascorbic acid and a 50 ℃ water bath for 20 min resulted in the highest sensitivity for Hg.A nearly 30 times signal enhancement factor could be achieved,and the detection limit of Hg was 1 ng· L-1.The calibration curve had a good linearity in the concentration range of 0.005-10.0 μg · L-1 with correlation coefficients above 0.999.The repeatability of the proposed method was obtained at 0.1 μg · L-1 of Hg2+ with the relative standard deviations (RSDs) of 5.6％ by seven replicates.Besides,the mechanism for signal enhancement was investigated and discussed.