Validation of methods for determination of lead and cadmium content in butterfly pea flowers (Clitoria ternatea) in the Cai Rang district, Can Tho city by atomic absorption Spectrophotometer AAS

The content of cadmium (Cd), lead (Pb) was determined in butterfly pea flower samples by atomic absorption Spectrophotometer (AAS). Method validation was evaluated through of parameters such as linear range, the limit of detection (LOD), the limit of quantitation (LOQ), recovery, repeatability, and intermediate precision. The validation results showed that the LOD of Cd, Pb were 1.20 and 6.20 μg/kg, respectively, while the LOQ of Cd and Pb were 4.01 and 20.5 μg/kg, respectively. The recovery of Cd is 96 - 98% and Pb is 98 - 100%. The relative repeat standard deviation (RSDr) of Cd, Pb is in the range of 1.50 - 2.50% and 1.90 - 2.13%, respectively. Meanwhile, the intermediate precision of Cd, Pb is 2.02% and 1.97%, respectively. The working range of the method is 0.2 - 4 μg/L (Cd) and 3 - 30 μg/L (Pb) with the standard curve equations having the correlation coefficient R2 ≥ 0.995. The quantitative method of Cd, Pb by atomic absorption Spectrophotometer is accurate and highly reliable, used to analyze butterfly pea flower samples collected in Cai Rang district, Can Tho city.