Abstract:
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 HNO
3-HCl-H
2O
2-HF mixture solution;2)the optimum conditions for determining Hg were:the HCl concentration in carrier solution 5%(v/v), NaBH
4 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.