Rapid Detection of Exogenous Bovine Insulin in Camel Milk Based on Dispersive Liquid-Liquid Microextraction

To addresses technical bottlenecks such as the complexity of the camel milk matrix and the interference of endogenous proteins with target detection, this study established an analytical method to detect exogenous bovine insulin in camel milk using dispersive liquid-liquid microextraction (DLLME) coupled with high performance liquid chromatography (HPLC). The extraction conditions and the instrumental parameters were optimized. The results showed that efficient enrichment and accurate quantification of target analytes in complex milk matrices were achieved by HPLC combined with DLLME using 0.01 mol/L HCl as the extractant, volume fraction 60% aqueous acetone as the extraction solvent, and n-hexane as the separation phase. The method exhibited good linearity for bovine insulin over the concentration ranges of 5-500 μg/mL (R² = 0.999). Recoveries for blank sample of Bactrian camel milk from Dabancheng District, Ürümqi ranged from 64.1% to 86.9% at spiked levels of 5, 50 and 500 μg/mL, with relative standard deviations (RSDs) of 4.9%-12.4%. The limit of detection and limit of quantification were 0.5 and 5 μg/mL, respectively. The DLLME-HPLC method is characterized by simple operation, short pretreatment time, and high analytical efficiency, providing technical support for rapid screening of exogenous bovine insulin in camel milk.