| A high performance liquid chromatographic (HPLC) method for the determination of 11 adulterated drugs (acetaminophen,aspirin,salicylic acid,sulfapirazinmetossina,sulfadiazine,sulfamethazine,ofloxacin,ciprofloxacin,lomefloxacin,terramycin and doxycycline) in herbal tea was developed.The samples were extracted ultrasonically with methanol-acetonitrile (1∶1),and the extracts were separated on an Agilent Poroshell 120 EC C18 column (100 mm×4.6 mm,2.7 μm) with trifluoroacetic acid triethylamine (pH 3.0)-methanol-acetonitrile as mobile phases by gradient elution.The flow rate was 1.2 mL/min and the column temperature was 35 ℃.Identification of 11 compounds was achieved by the comparison of the chromatographic peaks retention times and the DAD spectra between the samples and reference substances.Quantification analysis was performed by the external standard method.The calibration curves showed good linearities in the range of 0.5-25 mg/L with correlation coefficients not less than 0.998 2.The detection limits of 11 compounds ranged from 1 mg/L to 5 mg/L.The average recoveries ranged from 86.9% to 108.0% with RSDs of 0.5%-1.4%.The method was applied in the analysis of 286 herbal tea samples,and 9 positive samples containing acetaminophen,aspirin,salicylic acid and sulfapirazinmetossina were found.The positive samples were further identified and verified by HPLC-MS/MS.The experimental results indicated that the proposed method was simple,sensitive and accurate,and was suitable for the determination of 11 adulterated drugs in herbal tea. |