GF-AAS Determination of Heavy Metal Elements in Shuanghuanglian Oral Liquor and Its Raw Medicines with Microwave Assisted Sample Digestion

Sample of Shuanghuanglian Oral Liquor and its raw medicines (i.e. Lonicera, Forsythia suspensa and Baicalin) were soaked overnight with mixture of HNO3 and H2O2(3+1), and then digested in the microwave digestor. The lead, cadmium, chromium, copper, iron and zinc in the sample solution were determined by GF-AAS. Ammonium dihydrogen phosphate was used as matrix modifier for the determination of Pb, Cd, Cu and Fe, 8-hydroxyquinoline as matrix modifier for Cr, and selenium for Zn. Under optimized working conditions of the instrument, values of recovery and RSD′s (n=5) found were in the ranges of 90.4%-106.0% and 1.8%-4.6% respectively. As shown by the experimental results, the oral liquor was rich in Fe, Zn and Cu, while the contents of harmful elements Pb and Cd were found to be lower than that qualified in the “green trade standard”.