The Mineral Content of Rhizona cyperi after Microwave-Assisted Digestion and Determination by AAS

Rhizoma cyperi (tuberal part of Cyperus rotundus Linn) obtained from 15 different zones of China was studied to determine the contents of 16 trace elements such as 4 minor (Ca, K, Mg, and Na), 9 trace (Co, Cr, Cu, Fe, Mn, Mo, Ni, V, and Zn), and 3 toxic (Ag, Cd, and Pb) elements. The concentration determination of 16 elements was performed by atomic absorption spectrophotometry (AAS) after microwave-assisted digestion. A microwave-assisted digestion procedure based on the mixture nitric acid-hydrogen peroxide was evaluated. The method was successfully validated with the good recoveries (97-105%) against CRM GBW07603 (bush twigs and leaves). The calibration curve furnished good linear correlation coefficients (r=0.9956-0.9999), excellent recoveries (99.35-103.7%), and limits of detection (LOD=1-50ng center dot mL-1) suitable to determine in Rhizoma cyperi. The results showed that K, Ca, Mg, and Na were the most abundant of the major elements in Rhizoma cyperi with average concentrations of K, 26,221 mu g center dot g-1; Ca, 1097 mu g center dot g-1; Mg, 714 mu g center dot g-1, and Na, 293 mu g center dot g-1, respectively. K element was determined for the first time in this plant.