Residual Analysis of Aflatoxin M<sub>1</sub> in Cheese by HPLC Coupled with SolidPhase Dispersive Extraction and Solid-Phase Fluorescence Derivatization Method, and Its Accuracy Management for Method Validation

A sophisticated pretreatment method that combines solid-phase dispersive extraction (SPDE) and fluorescence derivatization using immunoaffinity (IA) gel was developed to analyze aflatoxin M1 (AFM1) in cheese by liquid chromatography. Cheese samples were homogenized adding acetonitrile/methanol/purified water mixture (6:1:3, v/v/v), followed purification SPDE. Trifluoroacetic acid added the IA for on-site derivatization. Recovery experiments (high concentration = 1 ng/g low 0.1 ng/g) performed. The limit of detection (S/N 3) AFM1 0.006 ng/mL, quantification > 10) 0.02 ng/mL. repeatability intermediate precision < 12% 14%, respectively, accuracy 109–116%. For external control, calculated HorRat values less than 2 both high- low-concentration samples. survey 10 commercial cheeses performed, trace amounts detected cottage mascarpone cheeses. In proposed method, validity, reliability, practicality, robustness demonstrated. By SPDE combination analysis, during clean-up realized, leading simplification operation.