Objective: To establish an method for determination of methyl nonyl ketone in Maozhiqing Oral Liquid. Method: The methyl nonyl ketone was determined by gas chromatography with Rtx-1 capillary chromatographic column(0.25 mm×30 m

0.25 μm). Column temperature: 80℃ for 2 min

increased at 10℃·min-1 to 220℃

then 20℃·min-1 to 270℃. Injector temperature: 240℃

FID temperature: 280℃. Injector volume was 1 μL; Split ratio was 30: 1. Nitrogen was used as carrier gas

the flow of column was 1.13 mL·min-1. Air: 400 mL·min-1. Hydrogen: 40 mL·min-1. Result: Methyl nonyl ketone has a good linear relationship with the peak area within the range of 0.032 1-0.641 6 g·L-1 with an regression equation being Y=3.00×106X-19 844(r=0.999 8). The average recovery was 97.76% and the relative standard deviation was 1.82%. Conclusion: The established method of gas chromatography can be used for quality control of Maozhiqing Oral Liquid because of its simplicity

accuracy

high sensitive and good reproducibility.