In-syringe dispersive micro-solid phase extraction method for the HPLC-fluorescence determination of aflatoxins in milk

The simultaneous determination of aflatoxins (B1, B2, M1 and M2) in milk using a new sample pretreatment technique, the in-syringe dispersive micro-solid phase extraction (ISDμSPE), coupled with high performance liquid chromatography with fluorescence detection is described. The separation of the aflatoxins were performed using C18 Hypersil gold (250 mm × 4.6 mm, 5 μm) column at 40 °C under gradient elution for 35 min. The excitation and emission wavelengths of the fluorescence detector were at 360 nm and 440 nm, respectively. On-line photo-chemical derivatization was used to enhance the detection of aflatoxin B1. Several parameters such as type and amount of sorbent, vortex speed, vortex time and elution solvent were evaluated. Limits of detection (LOD) ranged from 0.003 to 0.005 ng mL−1, limits of quantification (LOQ) ranged from 0.01 to 0.02 ng mL−1, recoveries ranged from 73.0 to 109.6%, and relative standard deviations (RSDs) was less than 17.3%. The proposed method was succesfully applied to the analysis of aflatoxins in milk.