Extração em fase sólida molecularmente impressa de acesso restrito acoplada à espectrometria de massas para determinação de anti- helmínticos em amostras de leite

Abstract

The analysis of organic compounds in complex biological samples poses a challenge due to the presence of interferents, such as proteins. In conventional approaches, protein precipitation is a prerequisite before extraction, often resulting in increased analytical errors. In this context, multifunctional materials, particularly restricted-access molecularly imprinted polymers coated with bovine serum albumin (RAMIP-BSA), have emerged as a promising alternative. These materials can selectively adsorb analytes while excluding macromolecules, significantly enhancing analysis efficiency. Regarding analytical techniques, electrospray ionization tandem mass spectrometry ESI-MS/MS successfully identifies and quantifies polar organic molecules, including drugs at low concentrations. In this context, an integrated online extraction/analysis system was developed, combining the advantages of RAMIP-BSA and mass spectrometry for identifying and quantifying benzimidazole anthelmintics in milk samples, without the need for chromatographic separation. Initially, a selective RAMIP for mebendazole (MBZ) was synthesized using the in-bulk method, with methacrylic acid as the functional monomer and glycidyl methacrylate as the hydrophilic co-monomer. Subsequently, epoxide ring opening was performed, and the polymer was coated with bovine serum albumin, generating RAMIP-BSA. In an online system, a mini-column packed with this adsorbent was coupled to the ESI-MS/MS mass spectrometer. Milli-Q water was employed as the loading and reconditioning mobile phase, while the cleaning and elution phase consisted of a solution containing 1% formic acid in water and methanol. The flow rate was maintained at a constant 0.5 mL min-1

. This system enabled simultaneous extraction, identification, and quantification of mebendazole (MBZ) and albendazole (ABZ) in milk samples. The method demonstrated linearity within the range of 10.0 to 125.0 μg L−1

(with a correlation coefficient

exceeding 0.99). The quantification limits were determined to be 15.0 μg L−1

for MBZ and

10.0 μg L−1

for ABZ, respectively. Precision and accuracy values were suitable, with all tested concentrations yielding results below 15%. The developed method was employed for the analysis of MBZ and ABZ in real milk samples and proved to be a viable alternative to conventional sample preparation and chromatographic techniques.