ABSTRACT
A single-laboratory validation (SLV) study was conducted for the determination of sodium fluoroacetate in dairy powders by LC-tandem MS (LC-MS/MS). Linearity of response was confirmed by analysis of samples fortified over the concentration range 0.10-100 µg/kg. The LOD was estimated to be 0.028 µg/kg (0.028 ppb) from the SD of the measured concentrations of infant formula samples fortified at 0.10 µg/kg. The corresponding LOQ calculates at 0.085 µg/kg (0.085 ppb), which ensures excellent reliability of quantification at the limit of reporting of 1.0 µg/kg (1 ppb). Repeatability and intermediate precision were estimated from the SD of the recovery of samples fortified at 0.075, 0.10, 0.20, 0.50, 1.0, and 10.0 µg/kg. The previously mentioned method performance values were established using a representative stage 2 (6-12 months) bovine infant formula, and the robustness of the method was tested by the analysis of 107 unique dairy powders and formulations fortified at 1.0 µg/kg. The data collected in this study satisfy the requirements of SLV studies established by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN), and the method was awarded First Action Official Method(SM) status by the AOAC Expert Review Panel on SPIFAN Nutrient Methods (Contaminants) on March 17, 2015.
