Determination of Hg in Tipping Paper with Cold Vapor Atomic Absorption Spectrometry

A method for determining mercury(Hg)in tipping paper with microwave digestion-cold vapor atomic absorption spectrometry was developed, the influencing factors, such as microwave digestion, HCl(reaction medium)concentration, NaBH4(reducing agent)concentration and carrier gas flow rate, etc.were investigated, and the contents of Hg in 16 domestic tipping paper samples were determined with the established method.The results showed that:1)the samples were completely digested under microwave in HNO₃-HCl-H₂O₂-HF mixture solution;2)the optimum conditions for determining Hg were:the HCl concentration in carrier solution 5%(v/v), NaBH₄ concentration 0.3%(m/v)and the flow rate of carrier gas 95 mL/min;3)the recoveries of Hg was from 90.0% to 98.0 % with RSDs of ≤ 3.0% and limit of detection of 0.016 μg/L;4)the Hg content in no sample was higher than 0.6 mg/kg, in 6 samples was from 0 to 0.1 mg/kg, 7 samples from 0.1 to 0.5 mg/kg, 1 sample 0.599 mg/kg, and 2 samples not detectable.