Determination of benzo(a)pyrene and aflatoxins (B1, B2, G1, G2) in vegetable oil by GPC-HPLC-FLD

Abstract

This study develops a gel permeation chromatography-high performance liquid chromatography-fluorescence detection (GPC-HPLC-FLD) method for determination of benzo(a)pyrene and aflatoxins (B1, B2, G1, G2) in vegetable oil. In the method, sample is extracted with ethyl acetate/cyclohexane (1 : 1, v/v), and cleaned up with the GPC. The separation of target compounds is performed on a Extend C₁₈ column (4.6 × 250 mm, 5 μm) at 25 °C with methanol and 10 mmol L⁻¹ ammonium acetate solution as mobile phase with gradient elution at a flow rate of 1.0 mL min⁻¹. The injection volume was 10 μL, detection wavelengths were set at 360 nm (λ_ex) and 440 nm (λ_em) at 0–23 min, and 380 nm (λ_ex) and 408 nm (λ_em) at 23–35 min using FLD. The detection limits of benzo(a)pyrene and aflatoxins (B1, B2, G1, G2) were 0.5, 1.0, 1.0, 1.0 and 1.0 μg kg⁻¹, respectively. The linear detection ranges of benzo(a)pyrene and aflatoxins (B1, B2, G1, G2) are 0.5–25.0 μg kg⁻¹, 1.0–30.0 μg kg⁻¹, 1.0–10.0 μg kg⁻¹, 1.0–30.0 μg kg⁻¹, 1.0–10.0 μg kg⁻¹ with correlation coefficients (R²) of 0.9998, 0.9999, 0.9997, 0.9998, 0.9996, respectively. Recovery rates in vegetable oil spiked with target compounds are in the range of 82.6–101.6%, with the relative standard deviation of 4.85–9.84%. The real sample tests show that this simple and accurate method can be used for determination of benzo(a)pyrene and aflatoxins (B1, B2, G1, G2) in vegetable oil.