Determination of aflatoxins M1 and M2 in milk by multifunctional purification column and liquid chromatography

Examples of aflatoxins M1 and M2 in milk

Sample extraction：

4g milk samples were taken in a 50mL centrifuge tube, and 10mL of extraction liquid (pure acetonitrile) was added and mixed well

Vortex for 6min, put into centrifuge (8000r/min centrifuge for 20min), and take supernatant as sample extraction liquid

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 the purified extract, blow nitrogen until dry, redissolve with 1mL or 0.5mL of the initial mobile phase, filter through the microporous membrane, and analyze on the machine

HPLCDetection condition：

Y Mobile phase: phase A, water; B phase, acetonitrile-methanol (50:50, v:v)

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: 430nm

Experimental result：

Aflatoxins mixed liquid chromatogram

(AFM1 and M2 concentration is 2ng/mL)

Comparison of milk sample and milk labeling sample

(AFM1 and M2 spiked concentration is 2.5ng/g)

The minimum detection limit, recovery rate and repeatability of milk samples

(AFM1 and M2 spiked concentration is 2.5ng/g)