Analysis of clenbuterol in pig liver and muscle by high performance liquid chromatography-electrospray ionization mass spectrometry

For beta-agonist clenbuterol, its typical ion peaks at m/z 277, 259 and 203 in electrospray ionization mass spectrometry (ESI/MS) were found and elucidated. The high performance liquid chromatography (HPLC)-ESI/MS method for analyzing the residue of clenbuterol in pig liver and muscle was developed. With the optimal mobile phase of MeOH-10 mmol/L NH4Ac (45:55, V/V) at 0.9 mL/min and the separation column of 250 mm x 4.6 mm i.d. ODS, clenbuterol and the sample blanks can be completely separated with the retention time of 16 min. With 243 nm detection, the linear range was between 2 and 100 mg/L with the detection limit of 0.75 mg/L, the recovery of 95%-98% and the RSD less than 2.0%. Using the proposed HPLC-ESI/MS, clenbuterol can be accurately identified with both retention time and the typical ion peaks. The experimental results of the real biologic samples of pig liver and muscle show the residue content of clenbuterol can be accurately determined by ultraviolet detection when the residue of clenbuterol. was higher. For the residue of clenbuterol lower than its detection limit, the quantitative result was not able to obtain, however the accurately qualitative result can be made according to its typical ion peaks at corresponding elution time.