Online restricted access molecularly imprinted solid phase extraction coupled with electrospray ionization-tandem mass spectrometry for determination of mebendazole and albendazole in milk samples.

Multifunctional materials, such as restricted access molecularly imprinted polymers covered with bovine serum albumin (RAMIP-BSA), are effective alternatives for sample preparation techniques. This material selectively adsorbs analytes while excluding macromolecules, enhancing the analysis's efficiency. Among analytical techniques, ESI-MS/MS (Electrospray Ionization-Tandem Mass Spectrometry) has successfully identified and quantified various molecules, including trace-level drugs. Therefore, we proposed, for the first time, an integrated online extraction/analysis system that combines the benefits of RAMIP-BSA and ESI-MS/MS for analyzing mebendazole (MBZ) and albendazole (ABZ) in milk samples without the need for chromatographic separation. Initially, a RAMIP selective for MBZ was synthesized using the bulk method with methacrylic acid and glycidyl methacrylate. Then, the polymer was covered with bovine serum albumin. Subsequently, this adsorbent was packed in a small column and coupled with an ESI-MS/MS instrument in an online configuration. Milli-Q water was used as the loading and reconditioning mobile phases, and a solution of formic acid in methanol (1:100 v/v) was employed as the elution phase. The system enabled simultaneous extraction and determination of MBZ and ABZ in milk samples. The method exhibited linearity between 15.0 and 125.0 μg L-1 for MBZ and 10.0 and 125.0 μg L-1 for ABZ (with a correlation coefficient exceeding 0.99). The limits of quantification were 15.0 and 10.0 μg L-1 for MBZ and ABZ, respectively. Good precision and accuracy were achieved. The developed method was used to analyze MBZ and ABZ in real milk samples and proved to be a viable alternative to conventional sample preparation and chromatographic techniques.