Determination of rhubarb anthraquinones and illegally added chemical drugs in weight- loss functional foods

An analytical method using high performance liquid chromatography coupled with diode array detector( HPLC- DAD) was developed for determination of illegally added chemical drugs fluoxetine and bisacodyl,and rhubarb anthraquinones such as sennoside A,sennoside B,emodin,emodin monomethyl ether,rheinic acid,chrysophanol,barbaloin and aloe- emodin in weight- loss functional foods. The separation was performed on a Diamonsil C18column( 250 mm × 4.6 mm,5 μm) by gradient elution of acetonitril and 0.02 mol / L ammonium acetate solution( containing 0.4% acetic acid) at a flow rate of 1.0 m L / min: 0~5 min,85% B,5~25 min,85% B~35% B,25~50 min,35% B,50~55 min,35% B~85% B.The detection wavelength was 268 nm and the column temperature was25 ℃. The samples containing fluoxetine or bisacodyl were confirmed by two grade of fragmention comparison using electrospray ionization- quadrupole- time of flight mass spectrometer( ESI- Q- TOF/ MS). The correlation coefficient of standard curve for each component in linearity range was not less than 0.995,as well as the average recoveries were 90.3% ~ 104.7% with the relative standard deviations( RSDs) were not more than 5.0%. After determination of 25 weight- loss functional foods,the fluoxetine and bisacodyl were detected in 2 and 1 samples,respectively.The barbaloin and aloe- emodin were both detected in one of the 25 samples.The method is reliable,sensitive,accurate and reproducible.It can be used for the qualitative and quantitative determination of above 10 components in weight- loss functional foods.