Detection method and application of 2-methylimidazole and 4-methylimidazole in baked food

[0057] Detection of 2-MEI and 4-MEI in commercially available biscuits containing caramel pigment:

[0058] (1) Preparation of standard solution and working curve: prepare a mixed standard solution of 2-MEI and 4-MEI with 20% acetonitrile, and serially dilute to obtain 2-MEI concentrations of 5.3, 10.6, 42.2, 84.4, 105.5, 126.6, 168.8, 266.3 ng / mL, a series of mixed standard solutions with 4-MEI concentrations of 7.1, 14.2, 56.9, 113.7, 142.2, 170.6, 227.4, and 284.3 ng / mL, in which the concentration of 4-MEI-d5 is 88.44 ng / mL. Determination by adding standard method of blank matrix and quantification by internal standard method.

[0059] (2) Preparation of sample solution: Accurately weigh 3.0 g (accurate to 0.01 g) of the pulverized and mixed sample into a 25 mL stoppered colorimetric tube, add 88.44 μg / mL 4-MEI-d525 μL, and then add 10 mL of 5% trichloroacetic acid (containing 20% ​​methanol by volume) solution, vortexed to mix, ultrasonically oscillated for 30min, dilute ...

[0081] Detection of 2-MEI and 4-MEI in bread:

[0082] Standard curve making, sample processing and determination are the same as in Example 1. The contents of 2-MEI and 4-MEI in commercially available bread were lower than the detection limit.

[0083] Example 3: Detection of 2-MEI and 4-MEI in cookies

[0084] Standard curve making, sample processing and determination are the same as in Example 1. The measured contents of 2-MEI and 4-MEI in commercially available cookies were 11.48 μg / kg and 584.78 μg / kg, respectively.