Appraisal and validation of a method used for detecting heavy metals in poultry feed in Bangladesh

Low concentrations of heavy metals are toxic and pose a serious threat to human health and the environment. Therefore, regular assessments of the toxic metal content in poultry feed are crucial for evaluating feed quality and customer safety. It is difficult to determine the heavy metals in the poultry feed at the trace amount. Therefore, this study aimed to validate this method through the detection of three heavy metals, chromium (Cr), cadmium (Cd), and lead (Pb), in poultry feed samples.

Graphite furnace atomic absorption spectrometry (GF-AAS) method was used to analyze the heavy metals in poultry feed according to the guidelines given by the Council Directive 333/2007/EC, Commission Decision 657/2002/EC. In this study, various parameters such as linearity check, limit of detection (LOD), limit of quantification (LOQ), recovery percentage, precision checks, repeatability, reproducibility, and uncertainty measurement were considered to validate and assess the method following international guidelines. Heavy metals, such as Pb, Cr, and Cd, were analyzed from the feed samples in the laboratory using the GF-AAS method (Model: AA-7000 Shimadzu, Japan) with high purity argon as the inert gas, and the absorbance was read at wavelengths of 283.0, 357.9, and 228.8 nm, respectively.

The coefficient of variation (CV%) for system suitability and precision data was <10% for all the metals (Pb, Cr, and Cd) detected in this study. The overall CV% of repeatability and reproducibility ranged from 8.70% to 8.76% and 8.65% to 9.96%, respectively. The linearity of the calibration curves was excellent (r² > 0.999) at various concentration levels for the three different metals. The recovery (%) was found to be 94.53, 93.97, and 101.63% for Pb, Cr, and Cd, respectively. The LOD values in feed were 0.065, 0.01, and 0.11 mg/kg, and the LOQ values were 0.22, 0.03, and 0.38 mg/kg for Cr, Cd, and Pb, respectively. The values recorded for the measurement uncertainty (%) were 11.48, 4.43, and 12.42% for Cr, Cd, and Pb, respectively.

The results show that these study criteria or parameters have met the validated or acceptable range. Therefore, it is a reliable technique that can be used undoubtedly for the routine analysis of heavy metals in poultry feed samples across the globe.