Determination of Polyhexamethylene Biguanide in Compound Disinfectant Products by UHPLC-Q-TOF-MS

A method for the determination of polyhexamethylene biguanide in compound disinfectant products by ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UHPLC-Q-TOF-MS) was developed. The disinfectant sample of 2 mL was added to 4.0 mol·L^-1 hydrochloric acid solution of 2 mL and hydrolyzed in 95 ℃ water bath for 2.0 h. The solution was adjusted to weak acid and made its volume up to 10 mL by water, and filtered with 0.45 μm filter membrane. The sample solution was separated on Poroshell EC120 chromatographic column with the mixture of acetonitrile and 0.1% (φ) formic acid solution at different volume ratios as mobile phase for gradient elution. The characteristic ion (m/z 184.155 9) was extracted for quantification with ESI under positive ion full scan mode. As shown by the results, 8 characteristic ions were obtained from hydrolyzing polyhexamethylene biguanide hydrochloride. Linear relationship between mass concentration of polyhexamethylene biguanide and its peak area was kept in the range of 1.0-100.0 mg·L^-1, with detection limit (3S/N) of 1.0 mg·L^-1. Recovery test was made on blank samples by standard addition method, giving results of polyhexamethylene biguanide in the range of 99.5%-117%, and RSDs (n=6) of the determined values were in the range of 7.2%-8.1%. The method was applied to determination of polyhexamethylene biguanide in disinfection products from different manufacturers, and the mass fraction were 0.030%-0.110%.