DEVELOPMENT AND VALIDATION OF FLAME ATOMIC ABSORPTION SPECTROMETRY (FAAS) FOR THE DETERMINATION OF POTASSIUM IN STACHYS AFFINIS ROOTS

Tóm tắt

Stachys affinis was considered a food and a medicinal plant with the s of anti-oxidation, antibacteria, anti-inflammation... and contains high content of potassium in roots. In this study, for development of potassium in Stachys affinis, Box-Behnken model was applied to optimize the sample digestion followed by FAAS. The experimental variables chosen were ashing time (270 - 390 min), furnace temperature (450 - 650°C), and nitric acid concentration (16 - 64%). Concentration values of potassium were used as a response. The potassium concentration can reach as high as 17.74 ± 0.26 mg/g at the ashing time of 340 min, furnace temperature of 461°C, and nitric acid concentration 38%. The analytical method developed and validated according to ICH and AOAC guidelines met the requirements of selectivity,  precision ( RSD = 1.44%), accuracy (recovery rate ranged from 95.6% to 107.8%). The calibration curve was obtained using linear regression y = 0.1049x - 0.0102 (R² = 0.9991) in the range of potassium concentration from 0.2 ppm - 5 ppm. The LOD and LOQ values for potassium were 0.046 ppm and 0.138 ppm, respectively.