Metal levels in traditional Chinese and ayurvedic medicines

Abstract

The calcium, magnesium, nickel and zinc contents in seven Traditional Chinese Medicines (TCM) and four Ayurvedic Medicines (AM) purchased locally were determined using flame atomic absorption spectroscopy following five different digestion methods: four open wet hot plate with various mixturesof acids and/or H2O2, and microwave oven (MWO) with conc HNO3 and H2O2. Sodium and potassium levels were analysed using flame photometry after MWO digestion. Potassium had the highest mean level among the six metals analysed. MWO was found to be more effective for Mg, method M1 [conc HNO3 + H2O2 (30 %)] for Ca and Zn, and method M4 (aqua regia) for nickel. From replicate measurements, the inter-day precision of the flame photometric measurements for sodium and potassium was found to be 3.0–9.0% and 1.3–9.0 % respectively. Comparison of results obtained from standard calibration curves and standard addition indicated that the percentage difference of sodium content in the TCM Niuhuangchiehdu Pien and the potassium content in AM, Diabecon was 3.9 % and 0.22 % respectively, indicating that the matrix did not have much influence on the metal content.