Comparision of pretreatment procedures to detect lead content of tea by square wave stripping voltammetry
Square wave stripping voltammetry(SWASV) was a high sensitivity electrochemical methods to detect the trace metal ions. The paper compared 5 pretreatment procedures to detect lead content of tea by SWASV. Results showed that microwave digestion method had the least loss, the minimum blank value and the determination value was similar to GB. The precision and accuracy results are better. Followed was the extraction digestion, the value detecting by nitrate -perchloric acid(4∶1) digestion was similar to value of GB, but it was high blank values, poor stability. The results of nitrate-sulfuric acid(3∶1) digestion and hydrochloride bre-wing methods were unsatisfactory. Comprehensive evaluation, microwave digestion method was optimum method in five kinds of sample pre-treatment methods in the tea which applied in SWASV to rapidly determinate the trace lead.