Development and Ratification of a Precise Method (GF-AAS) Used for the Determination of Poisonous Metal Lead (Pb) in Dairy Cow Milk Sample Commonly Available in the Market of Bangladesh

Abstract

Milk is considered as an ideal food item, and it can be contaminated with the toxic metal (Pb) by various ways. The metal lead (Pb) exposes toxicity greatly when it accumulates gradually inside the body cavity of human or animal. The study is aimed at the detection of poisonous mineral lead in cow’s milk sample by Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) method.Besides, public health concern or issues in the food chain of the consumer world is also taken into consideration in this study. Though the method is a bit troublesome, but an attempt was made herein this study to make it easy access for the determination and method validation for the analysis of mineral content in milk sample by complying with the Council Directive 333/2007/E. For the ratification of this method, a pretty good number of criteria including linear range, limits of detection and quantifications, accuracy (%), measuring uncertainty, repeatability and reproducibility or precision checks etc., were assessed for the affirmation of the method. GF-AAS (Model: AA-7000 Shimadzu, Japan) technique was used for the analysis of poisonous element lead in dairy cow milk samples. Lastly, detection of Pb in milk samples was done with ultraviolet/visible detection set at 283.0 nm wave length. The method was confirmed complying with the international guidelines and acceptance values for system suitability, precision, linearity, uncertainty and accuracy or recovery % were met in all aspects. The Relative Standard Deviation (RSD) or Coefficient of Variation (CV%) for system suitability and precision was <10% for the metal (Pb) measured in the milk sample. The linearity of the calibration curves was excellent (r2>0.999) at various concentrations for the lead. The instrumental Limits of Detection (LoD) value in milk were 0.397 and the limits of quantification (LoQ) value in milk samples was 1.32μg//L, respectively, for Pb, And the method of LoD and LoQ for Pb being 0.993 and 3.30 μg/Kg, respectively. The overall recovery (%) found 98.98 for the metal (Pb). The overall RSD or CV% of reproducibility and repeatability percentages being 6.85 and 7.65%, respectively. The value for measurement uncertainty (%) was 7.0 for Pb. The developed validated parameters denote that it is an easy and economical method that can be applied greatly for the regular laboratory analysis of trace mineral element in cow milk samples. After all, the potential health of the consumer health or public health concern should not be ignored at all for the continual ingestion of toxic element contained in the milk, even though the toxic mineral content found in the supplied milk samples were within the acceptable range.