Determination of Residual Organic Solvents in Raw Medicinal Piroxicam by Head-Space Gas Chromatography

Four residual organic solvents, including ethanol, acetone, chloroform and toluene, in raw medicinal piroxicam were determined by head-space GC. The temperature and time chosen for equilibration of the sample in the head-space vessel were 65 ℃ and 30 min respectively. Capillary chromatographic column, Rtx-1 (0.25 mm×30 m, 0.25 μm) was used for the separation, and hydrogen FID was adopted in the determination. Under the optimum conditions, the 4 organic solvents were separated within 10 min, and the separation factor attained was more than 1.5. Linear relationships between values of peak area and mass concentration of the 4 organic solvents were obtained in definite ranges, with detection limit (3S/N) in the range of 0.043-0.114 mg·L-1. The proposed method was applied to the analysis of raw medicinal piroxicam, both ethanol and acetone was detected. Values of recovery found by standard addition method were ranged from 98.1% to 101.7%.