Recently on the network hot topic “earth pit sauerkraut” make the uproar, people can see the processing and production links can be so people sigh, and those who can not be naked eye identification of food safety hazards and how to identify it?
【 Aflatoxin 】
Aflatoxin (AFT) is a class of compounds with similar chemical structure, which are derivatives of dihydrofuran coumarin. Aflatoxins are secondary metabolites mainly produced by Aspergillus flavus and A. parasiticus, including B1, B2, G1, G2 and two other metabolites M1 and M2, among which M1 and M2 are isolated from milk. B1 is the most toxic and carcinogenic substance. The incidence of aflatoxin in food and feed is highest in hot and humid areas. They exist in soil, plants and animals, all kinds of nuts, especially easy to pollute peanut, corn, rice, soybean, wheat and other grain and oil products, mycotoxin is the most toxic mycotoxin, the harm to human health is very prominent.
[Preparation of sample solution]
The sample is ground to a fine size (less than 2mm) and accurately weighed 25g in a 250 mL corkscrew conical flask (vegetable oil: Weigh 10g, dissolve with n-hexane, and then dissolve with methanol water for extraction), add 5g sodium chloride and methanol-water (7+3) to 100mL, stir with homogenizer at high speed for 2min, centrifugal for 5min (speed 6000r/min). 15mL of supernatant was accurately removed, and the filtrate was placed in a 50ml measuring flask, diluted to scale with water, shaken well, filtered with microporous membrane (0.45um), and 20ml of filtrate was measured. The filtrate was eluted with 20ml of water through the immunoaffinity column at a flow rate of 3ml/min. The eluent was discarded to allow air to enter the column, and the water was extruded out of the column, and eluted with appropriate amount of methanol. Collect all the eluent, place it in a 2ml flask, dilute it to scale with methanol, shake well, and serve.
[Chromatographic conditions]
Chromatographic conditions of iodine derivative method:
Detector: fluorescence detector
Iodine derived mobile phase: methanol – acetonitrile – water
Flow rate: 1.0 mL/min
Column temperature 35 ℃
Injection volume: 20uL
Chromatographic conditions of photochemical derivation:
Detector: fluorescence detector
Photochemical derivatization: 254nm uv light derivatization
Mobile phase :(methanol – acetonitrile) – water
Flow rate: 1.0 mL/min
Column temperature 35 ℃
Injection volume: 20uL
