Determination of metals in Pork Lard: A rapid and low cost sample preparation by RP-DLLME

Abstract

ABSTRAT In this work, a new method was proposed for determination of Cu, Fe, Mg, Mn and Ni in pork lard by flame atomic absorption spectrometry (F AAS) was developed using reverse phase dispersive liquid-liquid microextraction (RP-DLLME) for sample preparation. The parameters such as type, volume and concentration of dispersing (n-propanol and isopropanol) and extracting (HNO3 and HNO3 + HCl (1:1 v/v) solvents, ultrasound and centrifugation time were evaluated. For the determination of analytes by F AAS, external using aqueous reference solutions was performed for the metals evaluated in the range from 0.25 to 1.5 mg L-1. The limits of quantification for Cu, Fe, Mg, Mn and Ni were 0.0106; 0.0136; 0.0042; 0.0169 and 0.0124 µg Kg-1, respectively. The accuracy was estimated to be between 95.64 to 104.42% and precision (RSD) less than 1% for all analytes. The method was applied to different brands of pork lard (n = 5), where the recovery was between 90.2 and 103.2% and RSD between 0.024 and 0.094. After that, a risk characterization was performed, in which it was obtained for Fe 0.43 to 2.79% and for Mg 0.21 to 4.22% in relation to the recommended daily intake and for Ni 5.13 to 25.83% to the tolerable upper intake level. The risk quotient was less than 1 x 105 so that even sensitive populations are unlikely to suffer adverse effects.