The Development and validation of an RP-HPLC-FD method for the multi-residue analysis of antiparasitic macrocycliclactones in cattle edible tissues.

A method was developed and validated for the simultaneous determination of five macrocyclic lactones (ivermectin, abamectin, doramectin, moxidectin, and eprinomectin) in edible tissues (meat, liver, kidney, and fat) of cattle using a modified QuEChERS extraction procedure. Residue levels were determined by high-performance liquid chromatography with fluorescence detection. Recovery rates for all drugs across all edible tissues ranged from 73.91 to 96.15%. The limits of detection and quantification for macrocyclic lactones in cattle edible tissue samples ranged from 0.85 to 1.25 µg/kg and 2.55 to 3.80 µg/kg, respectively. Application of the method to real samples revealed the presence of macrocyclic lactone residues in 18 of 168 samples evaluated. One cattle meat sample (40 µg/kg, ivermectin) exceeded the maximum residue limit, while all other positive samples were below their respective maximum residue limits. This developed and validated method offers an alternative for the simultaneous analysis of multiple macrocyclic lactone residues in cattle edible tissues intended for human consumption, thanks to fewer processing steps, lower solvent volume, and fewer chemicals. Unlike other methods in the literature, this technique uses a very small sample amount (1 g) and solvent volume (3 ml). While these findings indicate that the developed method can be applied to detect macrocyclic lactone residues in edible tissues of cattle, potential matrix effects should be carefully evaluated, especially in matrices with high lipid content, such as adipose tissue (fat), given the target compounds high lipophilicity.