Abstract:

A high performance liquid chromatography method for the determination of kathon in oral care products was established. It was dissolved in water and methanol, and after ultrasonic extraction and filtration, a column of C₁₈ column （250 mm×4.6 mm, 5 μm） was used. The mobile phase was methanol and water （45∶55,V/V） and the quantitatively analysis was carried out at a wavelength of 275 nm in 15 minutes. The results show that methylchloroisothiazolone （CMIT） and methylisothiazolone （MIT） have good separation performance, among which the linear range is 0.07-10 mg/L （R ²>0.999 0）. The limits of quantitation （LOQs） and detection （LODs） are 0.7 and 0.2 mg/kg, respectively. The recovery rate of the actual sample is 96.1%-101.4%, and the relative standard deviation （RSDs） is between 1.1% and 5.6%. The linear range of methylchloroisothiazolone is 0.2-30 mg/L （R ²>0.999 0）. The limits of quantitation （LOQs） and detection （LODs） are 2 and 0.6 mg/kg, respectively. The spiked recovery and relative standard deviation range of the actual samples are 96.0%-101.8% and 1.0%-2.9%, respectively. The detection of the kathon sample can be confirmed by liquid chromatography-tandem quadrupole mass spectrometry （HPLC-MS/MS）. The analytical method is simple, accurate and rapid, and it is suitable for the determination of kathon in oral care products.

Key words: kathon, oral care products, liquid chromatography, methylisothiazolinone, methylchloroisothiazolinone, liquid chromatography-tandem quadrupole mass spectrometry