GC Determination of Diethylene Glycol in Toothpaste

Diethylene glycol in toothpaste sample was extracted with mixture of methanol and water (mixed in the ratio of 4 to 1 by vol.),and after centrifuging,the supernatant solution was used for GC analysis.Chromatographic conditions for the determination were studied and optimized.DB-FFAP chromatographic column was used for separation and FID was used in the measurements.Linear relationship between values of peak area and concentration of diethylene glycol was obtained in the range of 5.0-500.0 mg·L-1.Detection limit (3S/N) of the method was found to be 2.5 mg·L-1.Test for recovery and precision were made at 3 different concentration levels,and values of recovery and RSD′s (n=7) found were in the ranges of 96.5%-97.2% and 1.7%-2.1% respectively.