Metals in pork lard: Determination by RP DLLME and FAAS, and risk estimation of daily intake

A new method for determining metals (Cu, Fe, Mg, Mn, and Ni) in pork lard was proposed by flame atomic absorption spectrometry (FAAS) using the reversed-phase liquid-liquid dispersive microextraction technique (RP-DLLME) in sample preparation. In optimizing the protocol, the dispersion solvents n-propanol and isopropanol were evaluated, as well as HNO₃ and HNO₃ + HCl (1:1 v v⁻¹) as extracting solvent, the effect of ultrasound and the centrifugation time for the separation of the aqueous extraction phase of the matrix. The estimated limits of quantification for Cu, Fe, Mg, Mn, and Ni were 0.0106, 0.0136, 0.0042, 0.0169, and 0.0124 mg kg⁻¹, respectively. The accuracy for the metals analyzed varied between 95.6 % and 104.4 %, and the precision (RSD) was estimated at around 1 %. Different brands of lard (n = 6) showed recoveries between 90.2 % and 103.2 %, with RSD between 0.024 % and 0.094 %. The estimated daily intake risk for the elements ranged from 0.43 % to 2.79 % for Fe, 0.21–4.22 % for Mg, and 5.13–25.83 % for Ni, of the maximum tolerable intake level. The estimated risk quotient for the metals analyzed was less than 1 ×10⁻⁵, indicating that it is unlikely that sensitive populations will be affected by lard consumption for the metals evaluated.