[Analysis of chlorophenol compounds contaminating food by LC/MS]

A simple method using a liquid chromatograph with a mass spectrometer has been developed for the determination of chlorophenols in food. mass spectral acquisition was performed in the negative mode by applying sungle ion monitoring. In LC separation, Cadenza CD-C18 and 10 mmol/L ammonium acetate-methanol were used as the column and mobile phase, respectively. Chlorophenols in food were extracted with methanol, and cleaned up with an Oasis HLB cartridge. The quantification limits were 0.2 ng/g for 4-chlorophenol, 2 ng/g for 2,6-dichlorophenol, 1 ng/g for 2,4-dichlorophenol and 0.5 ng/g for 2,4,6-trichlorophenol. The average rocoveries of chlorophenols from food at the spiked level of 20 ng/g were in the range of 70-85%. The relative standard deviations of all examined compounds were within 10%.