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

ABSTRACT

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 = 1–50 ng·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 µg·g⁻¹; Ca, 1097 µg·g⁻¹; Mg, 714 µg·g⁻¹, and Na, 293 µg·g⁻¹, respectively. K element was determined for the first time in this plant.

KEYWORDS:

• atomic absorption spectrophotometry
• microwave-assisted digestion
• Rhizoma cyperi
• trace elements

Notes

^a LOD: limit of detection.

^b LOQ: limit of quantification.

^a n = 5.

^b Means expressed as 95% tolerance limit.

^c Values in the parentheses are not certified.

^a n = 5.

^a n = 5.

^a Mean values; —: means not reported.