Inspection body: Only half an hour to detect whitening agent

How to detect the whitening agent in flour?　　6th, the reporter came to Jinan related inspection agencies, to understand the flour in the whole process of whitening agent detection. "The testing countries have relevant regulations, the process is not very complicated." "A Dragon surname inspection personnel introduction. The tester briefed the reporter on the entire testing process: generally 5 grams of flour samples placed in 50 ml colorimetric tube, add 10 ml methanol, mix in the vortex mixer, static, add potassium iodide aqueous solution 5 ml, mix evenly on the vortex mixer, static place, add water to 50 ml, mix evenly, static.　　The upper supernatant is then measured by liquid chromatography, and the standard series (benzoic acid or benzoyl peroxide) are quantitatively compared and then the chromatogram is drawn. "The principle of this method is to restore benzoyl peroxide in flour, to generate benzoic acid, to detect the content of benzoic acid by HPLC and to determine the content of benzoyl peroxide indirectly." "The tester introduced that if there is a peak in the chromatogram, it contains benzoic acid, which is indirectly measured in flour containing benzoyl peroxide (Brightener). The initial detection of the flour in the absence of whitening agent, about half an hour.