METHOD FOR DETECTING CONTENT OF FORMALDEHYDE IN TOFU SKIN

摘要

A method for detecting the content of formaldehyde in tofu skin, comprising the following steps: weighing 10 g of a tofu skin sample, adding a small amount of a stabilizer, shaking evenly and standing in an environment of 30-38 degrees for 50 mins; adding 10-15 ml of deionized water, placing in an ultrasonic cleaning machine for ultrasonic extraction, retrieving a filtrate; then placing same in an ultrasonic oscillator for 20 mins; fetching 5 ml of the filtrate into a flask, then adding ferric ammonium sulfate powder, shaking slightly the flask until all of the powder is dissolved; placing in water of 100 degrees away from light and heating for 35-50 mins; retrieving the reacted sample liquid, and standing for 15-25 mins then filtering via a microporous membrane. The product of the sample, when dried and digested by an ultrasonic water bath machine, obviates the need for an organic solvent for extraction, thus reducing loss in a derivative product, reducing labor intensity, saving medicaments, and, with time being reduced, experimental results detected per the method satisfy analysis requirements for the sample, and achieving the goal of quick detection.