Determination of salbutamol in livestock meat foods by electro-membrane extraction coupled with liquid chromatography-tandem mass spectrometry

To solve the problems of low salbutamol residue concentrations and severe matrix interference in various livestock meat foods, an analytical method has been developed for the determination of salbutamol in livestock meat foods using a novel electromembrane extraction（EME） technique combined with liquid chromatography-tandem mass spectrometry（LC-MS/MS）. The samples were extracted using acetonitrile, followed by selective separation, purification, and enrichment using EME. Salbutamol detection was performed in positive ion mode with multiple reaction monitoring on an LC-MS/MS instrument, and quantification was conducted using the external standard method. In EME, salbutamol was first converted into its ionic form by adjusting the pH of the solution. Two L-shaped platinum electrodes were put into the sample solution and acceptor solution as the cathode and anode, respectively. The other ends of both L-shaped platinum electrodes were connected to the electrophoresis power supply. Upon activation of the power supply and stirring device, salbutamol in the sample phase migrates directionally through the supported liquid membrane（SLM） into the acceptor phase. The results indicated that optimal extraction recovery of salbutamol was achieved under the conditions of an applied voltage of 80 V, a mixed solvent with a ratio of di-（2-ethylhexyl） phosphate to 2-nitrophenyl octyl ether of 2∶ 8 as the organic solvent, 20 mmol/L formic acid solution as the acceptor phase, and an extraction time of 30 min. This method exhibited a wide linear range of 1～1 000 ng/mL with a coefficient of determination（R²） ＞ 0.999 6. The limit of detection（LOD, S/N=3） and the limit of quantification（LOQ, S/N=10） of the method were 0.05 μg/kg and 0.17 μg/kg, respectively. The spike recovery experiments were conducted on four different samples of beef, lamb, pork, and pork liver, and the average recovery rates and relative standard deviations（RSDs, n=6） were 83.5% to 110% and 3.3% to 9.8%, respectively. This method has the characteristics of strong sample purification ability, rapid mass transfer rate, high sensitivity, and simple operation, etc., making it suitable for highly sensitive and accurate determination of salbutamol in various livestock meat foods.