Determination of aflatoxins in rapeseed oil by liquid chromatography

Application of aflatoxins in rapeseed oil

Sample extraction：

Measure 5g rapeseed oil sample into 50mL centrifuge tube, add 20mL extraction solution (84% acetonitrile-aqueous solution) and mix well

Ultrasonic extraction 30min, centrifuge (8000r/min) for 20min, take the supernatant as the sample extraction solution

Sample purification：

Step 1: Add 5mL of sample extract to the test tube

Step 2: Insert the rubber tip of the purification column into the test tube from the top of the test tube, and press the purification column down to the bottom of the test tube

Step 3: Pour the purified sample extract from the upper part of the column into the sample bottle or EP tube

Step 4: Take 2mL of purified extract, blow nitrogen until dry, redissolve with 1mL or 0.5mL methanol, filter through microporous membrane, and then analyze on machine

HPLCDetection condition：

Y Mobile phase: phase A, water; Phase B, methanol

Equal gradient elution condition: A, 70%; B, 30%

Y column: C18 column (column length 250mm, column inner diameter 4.6mm, packing particle size 5μm)

Flow rate: 1.0mL/min

Y column temperature: 40℃

Y Sample size: 50μL

Fluorescence detection: excitation wavelength: 360nm; Emission wavelength: 440nm, derived after photochemical column

Aflatoxins mixed liquid chromatogram

(AFG1 and B1 concentrations were 4ng/mL; AFG2 and B2 concentrations were 1ng/mL)

Liquid chromatogram of blank sample of rapeseed oil

Liquid chromatogram of rapeseed oil blank labeled sample

(The concentration of AFG1 and B1 was 4ng/g; The concentration of AFG2 and B2 is 1ng/g)

The minimum detection limit, standard recovery and repeatability of rapeseed oil samples

(The concentration of AFG1 and B1 was 4 ng/g; The concentration of AFG2 and B2 is 1ng/g)