Fluorimetric method based on diazotization-coupling reaction for determination of clenbuterol.

A novel fluorimetric method based on diazotization-coupling reaction (DCR) for the determination of clenbuterol is described. In acidic solution, clenbuterol was first diazotized with sodium nitrite, followed by coupling with bisphenol A to produce an azo-compound in NH3- NH4Cl buffer. It has found the diazotized clenbuterol- bisphenol A- NH3- NH4Cl (DCBN) system has strong fluorescence efficiency compare with the bisphenol A solution. There is a linear relationship between the increased intensity of the fluorescence emission spectra (λex/λem = 276 nm/306 nm) and the concentration of clenbuterol. The effects of the amount of sodium nitrite, diazo reaction time, the amount of bisphenol A, coupling reaction time and coupling reaction temperature have been examined. Under the optional conditions, clenbuterol can be determined over the concentration range of 0.02 to 2.0 μg mL(-1) with a correlation coefficient of 0.9953. The detection limit is 0.01 μg mL(-1) at a signal-to-noise ratio of 3. The relative standard deviation (RSD) for 11 repetitive determinations of 0.9 μg mL(-1) clenbuterol is 0.22 %. The utility of this method was demonstrated by determining clenbuterol in meat samples.