The phenyl content is an important quality parameter for phenyl silicone oils, yet its current determination method by 1H NMR is still unsatisfactory due to the potential interference of methylphenylcyclosiloxane or solvents such as toluene and xylene. Herein, a novel method has been developed for the determination of the phenyl content in phenyl silicone oils by gel permeation chromatography-ultraviolet detection (GPC-UV) analysis. Under optimized parameters, the standard curve has been established in the linear range of 5-1000 µg/mL with a squared correlation coefficient of more than 0.999, and a quantification limit of 0.972 µg/mL. The GPC-UV method can easily exclude potential interfering substances, such as methylphenyl cyclosiloxane, toluene or xylene, and various silicone oils. The phenyl content in 9 available phenyl silicone oil samples was determined with a recovery in the range of 84.63%-106.74%. The determined phenyl content of sample H1 by GPC-UV was in good agreement with that (0.603 mg/g) by the 1H-NMR analysis.

The phenyl content is an important quality parameter for phenyl silicone oils, yet its current determination method by 1 H NMR is still unsatisfactory due to the potential interference of methylphenylcyclosiloxane or solvents such as toluene and xylene. Herein, a novel method has been developed for the determination of the phenyl content in phenyl silicone oils by gel permeation chromatography-ultraviolet detection (GPC-UV) analysis. Under optimized parameters, the standard curve has been established in the linear range of 5-1000 µg/mL with a squared correlation coe cient of more than 0.999, and a quanti cation limit of 0.972 µg/mL. The GPC-UV method can easily exclude potential interfering substances, such as methylphenyl cyclosiloxane, toluene or xylene, and various silicone oils. The phenyl content in 9 available phenyl silicone oil samples was determined with a recovery in the range of 84.63%-106.74%. The determined phenyl content of sample H1 by GPC-UV was in good agreement with that (0.603 mg/g) by the 1 H-NMR analysis.