Determination of ochratoxin in flour by multifunctional purification column and liquid chromatography

Application of ochratoxin in flour

Sample extraction：

Weigh 5g flour sample into a 50mL centrifuge tube, add 20ml extraction solution (84% acetonitrile-aqueous solution) and mix well

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

Sample purification：

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

Step 2: Insert the rubber tip of the column into the test tube from the top and press the 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 purified extract, blow nitrogen to dry, redissolve with 0.4mL initial mobile phase, filter through microporous membrane, machine analysis

HPLCDetection condition：

 Mobile phase: acetonitrile-water-glacial acetic acid (96+102+2)

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

Flow rate: 1.0mL/min

 column temperature: 35℃

 Injection size: 50μL

Detection wavelength: excitation wavelength 333nm, emission wavelength 460nm

Experimental result：

Ochratoxin liquid chromatography

(Ochratoxin concentration was 20.0ng/mL)

Comparison of flour sample and flour labeling sample

(Ochratoxin concentration is 16.0ng/g)

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

(Ochratoxin concentration 16.0ng/g)