原子荧光光谱法测定化妆品中汞的结果不确定度评定

本文介绍了原子荧光光谱法测定化妆品中汞的不确定度评定方法 ,分析和识别在分析过程中的不确定度来源 ,较为全面地评定了测量不确定度。根据最小二乘法原理计算校准曲线的标准不确定度 ,采用极差法评定测量次数较少时引起的标准不确定度。对原子吸收法、电感耦合等离子体 -原子发射光谱法和原子荧光光谱法等测定结果的不确定度的评定具有参考作用。     

Acid Effects on the Measurement of Mercury by Cold Vapor Atomic Absorption Spectrometry

Abstract

The influence of nitric, hydrochloric and sulfuric acids on the measurement of mercury by cold vapor atomic absorption spectrometry has been investigated. Small pre-reduction peaks associated with the instability of mercury were observed in solutions containing ≤ 12.5, < 2 and ≥ 12.5% v/v of each acid, respectively. Mercury was found to be most stable in ≥, 2% v/v hydrochloric acid and the measured absorbance was not greatly influenced by varying concentration of the acid. The mercury absorbance measurements were more sensitive in solutions containing ≤ 6.3% v/v hydrochloric acid than in similar concentrations of nitric and sulfuric acids. The use of the three acids as a digestion mixture result in serious interference from nitrogen oxides. The interferant was removed by use of expelling agents such as urea and sulfamic acid or overcome by use of excess stannous chloride, prior to the reduction of mercury(II) ions. The determination of mercury in NBS albacore tuna using both of these approaches to overcome the interference problem proved to be successful.