Fast determination of sulfonamides from egg samples using magnetic multiwalled carbon nanotubes as adsorbents followed by liquid chromatography-tandem mass spectrometry

A simple and effective method based on magnetic separation has been developed for the extraction of sulfonamides (SAs) from egg samples using magnetic multiwalled carbon nanotubes (MMWCNTs) as an adsorbent. The MMWCNTs were simply prepared by depositing Fe₃O₄ onto MWCNTs that had been previously oxidised. The extraction procedure was carried out in a single step by blending and subsequently stirring the mixture of MMWCNTs and aqueous egg samples. The SAs were first extracted as described above, adsorbed onto the MMWCNTs directly and finally analysed by liquid chromatography-tandem mass spectrometry. The limits of detection obtained are in the range of 1.4-2.8 ng g^-1. The proposed method was successfully applied in determining SAs in the eggs obtained from laying hens fed with SA standards, and compared to eggs purchased from local markets. The results demonstrate that SAs were detectable in the incurred egg samples.