Extraction and determination of sulfadiazine and sulfathiazole in milk using magnetic solid phase extraction-HPLC-UV

Abstract

Sulfonamides are heat-stable antibacterial drugs and their residues in milk increase the risk of human exposure and may cause food-borne illness. In this study, Fe₃O₄ magnetic nanoparticles (Fe₃O₄ MNPs) have been successfully used for the extraction of sulfadiazine (SDZ) and sulfathiazole (STZ) from milk samples. The effect of the amount of magnetic adsorbents, volume of extracted milk and sample pH were investigated and optimized. The experimental results showed that the suggested method possessed suitable analytical performance. Linearity was obtained over a concentration range of 0.25, 0.5, 1.0, 2.0 and 4 MRL with regression coefficients ranging from 0.9985 to 0.9978 for SDZ and STZ. The limits of detection (LOD) and quantification (LOQ), for the two analytes, were 10 and 30 ng mL⁻¹, respectively. The proposed method was used for the analysis of different milk samples, and excellent recoveries in the range of 92.9–102.4% were obtained. These results indicated that the proposed method can be broadly used in the monitoring of low concentrations of drugs in milk samples and open fascinating perspectives in future studies.