Simultaneous Determination of Related Substances Benzaldehyde and Toluene in Benzoic Acid Crude Drug by RP-HPLC

OBJECTIVE:To establish a method for the determination of related substances benzaldehyde and toluene in benzoic acid crude drug.METHODS:RP-HPLC method was adopted.The determination was performed on Wondasil TM-C 18 column with mobile phase consisted of methanol-0.02 mol/L ammonium acetate(pH 4.0)(80:20)at the flow rate of 0.5 ml/min.The detection wavelength was set at 254 nm.RESULTS:Benzoic acid,benzaldehyde and toluene could be separated completely.The linear range of benzaldehyde and toluene were 2.0-7.2 μg/ml(r=0.999 5)and 1.75-6.30 μg/ml(r=0.998 9)respectively.The detection limits were 0.05 μg/ml and 0.2 μg/ml.The average recoveries were 100.57%(RSD=0.99%,n=9)and 99.58%(RSD=0.86%,n=9),respectively.CONCLUSIONS:This method is sensitive and accurate,and it can be used for the simultaneous determination of related substances benzaldehyde and toluene in benzoic acid crude drug.