Abstract:Pentafluorophenylhydrazine derivatization liquid chromatography was performed to analyze the residual formaldehyde in fruits and vegetables under different digestion dynamics conditions, as well as to detect the background level of formaldehyde in various fruits and vegetables. Results showed that the digestion rate of formaldehyde in fruits and vegetables was associated with the storage medium. The digestion rate in water was significantly faster than that in air. The main factors affecting formaldehyde digestion in air were air temperature and the matrix of the fruits and vegetables; the higher the temperature, the faster the digestion. Digestion in water was related to water temperature, pH, and the matrix of the fruits and vegetables; the digestion speed in water at 50 ℃ was higher than that at 25 ℃; the digestion rate at pH 9 was higher than those at pH 7 and pH 5. Background levels of formaldehyde could be detected in 31 out of 32 types of fruits and vegetables. Among them, only Houttuynia cordata showed no detectable background level of formaldehyde. Relatively high background levels of formaldehyde could be detected in citrus fruits, such as mandarin and oranges, which reached 0.79 mg/kg~2.52 mg/kg, while formaldehyde contents in the other 30 kinds of fruits and vegetables were 0.08 mg/kg~0.61 mg/kg. These results provide reference data for the detection of formaldehyde content in fruits and vegetables.
