Determination of aflatoxin in chicken feed by multifunctional purification column and liquid chromatography

Application of aflatoxin in chicken feed

Sample extraction：

Measure 5g chicken feed sample (crushed and passed through 1mm sampling screen) into 50mL centrifuge tube, add 20mL extraction solution (95% acetonitrile-aqueous solution) and mix well

Ultrasonic extraction 30min, centrifuge (8000r/min centrifuge 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 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, 68%; B, 32%

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

Experimental result：

Aflatoxins mixed liquid chromatogram

(AFG1 and B1 concentrations were 5ng/mL; AFG2 and B2 concentrations were 1.5ng/mL)

Comparison of chicken feed negative samples and negative labeled samples

(AFG1 and B1 were 10ng/g; The concentration of AFG2 and B2 is 3ng/g)

The minimum detection limit, standard recovery and repeatability of chicken feed samples

(AFG1 and B1 were 10ng/g; The concentration of AFG2 and B2 is 3ng/g)