Comparison of ICP-MS and direct mercury analyzer for the analysis of mercury in pharmaceuticals

Abstract

Mercury (Hg) is a harmful heavy metal and non-essential element. Also Hg has bioaccumulating characteristics and is rated as one of the most hazardous heavy metals. It seems very toxic at only trace amount. But Hg is found at various foods and cosmetics as part of an ingredient by chance. Unintended contamination of Hg may be introduced in the products from raw materials and in the process of production and it may be trace level. This study compared the determination method for mercury by instruments (Hydra-IIC and ICP-MS). One method for mercury determination was by the Hydra-IIC direct mercury analyzer (Teledyne Leeman Labs, Hudson, NH, USA). The Hydra-IIC have fully automated operation and pre-treatment is unnecessary. The other was by inductively coupled plasma-mass spectrometry (ICP-MS) in the CCT mode after microwave digestion in closed pressurized vessel. Each method was validated for limit of detection, linearity, accuracy and precision before comparison. The linearity of analyzing mercury obtained by two methods were very satisfied, with a coefficient of determination (r2) higher than 0.99. The limit of detections was 0.2 ng/g sample for Hydra-IIC and 2.0 ng/g for ICP-MS. The accuracies for both methods were 80% ˜ 120% and precisions were lower than 20% relative standard deviation. The concentrations of mercury in samples detected by two methods were comparable.