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Method validation of heavy metals determination in traditional herbal tablet, capsule and liquid by graphite furnace atomic absorption spectrometer and flow injection for atomic spectroscopy hydride system
Nor Hayati Abdullah, Ong Boo Kean, Nurhazwani Mohd. Hirmizi, Norulaiman Yusoff, Amiera Rina Nurdiana Mohd. Sabarudin

Abstract
The validation on the test method applied showed acceptable limits of detection (LOD), limits of quantification (LOQ), linearity, precision (repeatability and intermediate precision) and accuracy. The LOD and LOQ for cadmium (Cd) were acceptable at below 1.0 ug/L, plumbum (Pb) 10 ug/L, arsenic (As) 5 ug/L, and mercury (Hg) 1.0 ug/L. The working linearity ranges were found as: 1-5 ug/L for Cd, 20-100 ug/L for Pb and As, and 10-30 ug/L for Hg. The correlation coefficient were found to be more than 0.995 each. All concentrations for each heavy metal in the linearity ranges showed repeatability of below 10% RSD value and accuracy in the range of 120-80%. Intermediate precision study within different days of same concentration for each analyts gave similar result with slight different but still in the acceptable range for all studied parameter. Therefore, the test method could be applied in performing routine analytical test in laboratory.

Keywords: Graphite Furnace Atomic Absorption Spectrometer (GFAAS); Flow Injection For Atomic 
Spectroscopy Hydride System (FIAS MHS); method validation; heavy metals; herbal product matrix.