Incorporation of Co-Cyromazine Complexes Onto Halloysite Nanotubes as a Spin-Tip Solid-Phase Extraction Sorbent for Determining Hydrophilic B Vitamins in Functional Foods

Quantifying hydrophilic B vitamins (B1 [(thiamine], B2 [riboflavin], and B3 [nicotinic acid]) in complex functional food matrices presents a significant challenge. Conventional sorbents, such as C18, often exhibit poor retention and low recoveries (50%–60%) due to weak hydrophilic interactions. To efficiently extract these target analytes from functional foods, a new sorbent with tailored hydrophilic affinity has been developed by incorporating Co-cyromazine complexes onto halloysite nanotubes. This composite was employed as the sorbent for a spin-tip solid-phase extraction method, which was coupled with liquid chromatography-tandem mass spectrometry analysis. Following comprehensive optimization and validation, the method demonstrates simplicity, accuracy, sensitivity, and cost-effectiveness. It requires only 10 mg (or 10 µL) of functional food sample, while delivering high recoveries (81.3%–107.8%) with good precision (relative standard deviations ≤10.7%). The limits of detection ranged from 0.4 to 2.5 ng/mL in liquid matrices and from 0.7 to 8.7 ng/g in solid matrices. Practical applicability was confirmed through the successful quantification of vitamins B1, B2, and B3 in various commercial functional foods. Consequently, the developed method provides a reliable and promising analytical tool for the determination of B vitamins, with the potential for extension to other hydrophilic analytes in biological and food matrices.