Optimization of the QuEChERS-UPLC-APCI-MS/MS method for the analysis of vitamins D and K nanoencapsulated in yogurt

A novel approach was developed to simultaneously determine the contents of vitamins D₂, D₃, K₁, and K₂ in yogurt fortified with nanoencapsulated vitamins D and K. This method combines QuEChERS extraction with UPLC-APCI-MS/MS analysis. Optimization of the QuEChERS process included fine-tuning the addition of salts using response surface methodology based on the Box-Behnken design. Under the optimized conditions, the developed method exhibited an excellent linearity (R² > 0.999) across concentrations ranging from 0.5 to 500 µg/L. The limits of detection and quantification (LOD and LOQ) were found to be 0.01-0.04 µg/L and 0.04-0.11 µg/L, respectively, with precision, accuracy, and recovery rates exceeding 94.88 %, and accompanied by acceptable relative standard deviations. Comparative analysis with traditional methodologies revealed the significant advantages of the proposed approach. Previous techniques such as liquid-liquid extraction combined with saponification are time-consuming and require high sample quantities. In addition, dispersive liquid-liquid microextraction requires a long analysis time and exhibits a poor sensitivity, particularly in terms of its LOD and LOQ values. In contrast, our method offers a straightforward, efficient, and reliable sample preparation technique suitable for detecting vitamins D₂, D₃, K₁, and K₂ in a yogurt matrix. This study not only demonstrates the feasibility of applying the QuEChERS method for stable vitamin quantification in yogurt, but it also represents an innovative contribution to enhancing the detection sensitivity and efficiency in food analysis. By emphasizing these methodological advancements and comparative benefits, this research underscores the significance of adopting advanced analytical approaches in food science.