The presence of heavy metals in infant formula has become a global concern. The most
common method to determine heavy metals is AAS. However, as this technique is lacking
in several aspects, including the instrument’s low sensitivity, a more sensitive instrument
such as ICP-MS is necessary. The Inductively Coupled Plasma Mass Spectrometry (ICPMS) was used in accordance with the standard method AOAC 2015.01 with modifications
on the microwave condition and the addition of hydrochloric acid (HCl) during the sample
digestion process. The modified standard method requires a validation process. This
research aimed to validate the method of analysis for the determination of Pb, Cd, Hg, As
in infant formula using ICP-MS and its application in formula milk. This research consists
of five stages: 1) instrumental performance; 2) homogeneity test; 3) method orientation; 4)
method validation; and 5) the application of the validated method to other products. The
findings in the research were: the method linearity was confirmed at working
concentration 5-30 µg/kg for all the heavy metals with R2
value of nearly 1,000; the
method limits of detection (LOD) were 0.74 µg/kg (Pb), 0.41 µg/kg (Cd), 0.08 µg/kg
(Hg), 0.50 µg/kg (As), while the method’s limits of quantification (LOQ) were 2.48 µg/kg
(Pb), 1.36 µg/kg (Cd), 0.27 µg/kg (Hg), 1.67 µg/kg (As); the method was found precise
with Relative Standard Deviation (RSD) below 2/3 RSD Horwitz and all the recovery
values were found to fall within the acceptable range (60–115%); the % RSD intra-lab
reproducibility was below RSD Horwitz; and the method was robust, indicating that it was
unaffected by small changes in its variables. The validated method can be applied
routinely to determine heavy metals in infant formula and formula milk.