UV Irradiation Controlled Cold Vapor Generation Using SnCl₂ As Reductant For Mercury Speciation Without Chromatographic Separation

Mercury is a very useful substance. It is used in many industry areas and physical-chemical laboratory. At the same time, we can not ignore the poison of mercury, and methylmercury is the most toxic state among mercury compounds. In environmental pollution caused by mercury, methylmercury does much more harm to people than other forms of mercury compounds. So it is meaningful for environmental, biological, medicinal to study the speciation analysis for mercury.A new , simple, fast and sensitive method was proposed for speciation analysis of inorganic mercury (Hg²⁺) and methylmercury (MeHg⁺) in aqueous samples. This method is based on cold vapor generation coupled to atomic fluorescence spectrometry. In the presence of UV irradiation, MeHg⁺ can be decomposed and total mercury (MeHg⁺ + Hg²⁺) in a sample solution can be reduced by SnCl₂. However, without UV irradiation, only Hg²⁺ species can be determined. Then the concentration of MeHg⁺ can be obtained from the difference of the total mercury and Hg²⁺, and thus speciation of Hg²⁺ and methylmercury was simply achieved without chromatographic separation. Experimental parameters such as the concentrations of SnCl₂ and hydrochloric acid, and irradiation time were optimized for the best analytical response. The effect of seven metal ions was examined, which may interfere with the determination. Under the optimized experimental conditions, the limits of detection of 0.02 ng · mL^-1 for Hg²⁺ and 0.01 ng · mL^-1 for MeHg⁺, respectively, were achieved. The proposed method was preliminarily applied to analysis of tap water samples.