Laboratory Performance Evaluation on Analysis of Cadmium and Lead in Herb through Participation in the Regional Laboratory Comparison APMP QM-P10

The ubiquitous presence of heavy metals in the environment arising from various natural and anthropogenic activities have led to the accumulation intrusion of these substances into agricultural products including herbal plants. With the rapid growth of herbal medicine trade market, extensive surveillance monitoring and laboratory testing of heavy metals in herbal samples are carried out worldwide nowadays. Those surveillance activities are very much rely on the quality of the data produced by analytical laboratory. As analysis of heavy metals have been one of several main interests of our laboratory of Research Center for Chemistry, then participation on the international laboratory comparison such as APMP.QM-P10: Cadmium and Lead in Herb is a valuable effort for evaluate laboratory performance in this area of analysis. Several trial run and validation had been performed on the proficiency samples, including sample preparation, level of method blanks, use of matrix modifiers, precision and also trueness check using suitable reference material. Z-scores of 0.787 and 1.105 for cadmium and lead respectively have obtained as result of participation. It was found that the z-scores were satisfactory compared to the satisfactory limit of -2 ≥ z-score ≤ 2. These results provide strong confirmation of maintained capability of Research Center for Chemistry on heavy metals analysis, particulary in herb.