Simultaneous determination of nine beta-blockers in porcine tissues by ultra-fast liquid chromatography coupled with quadrupole/linear ion trap mass spectrometry

A highly sensitive method using ultra-fast liquid chromatography coupled with quadrupole/linear ion trap mass spectrometry (UFLC-Q/Trap MS) was developed to simultaneously screen and confirm nine beta-blockers (BBs) in porcine tissues (porcine muscle, liver and kidney). The method was used for trace determination of atenolol, pindolol, acebutolol, metoprolol, carazolol, labetalol, bisoprolol, propranolol and penbutolol. The homogenized tissues were hydrolyzed by beta-glucuronidase/aryl sulfatase and extracted with acetonitrile, followed by continuous purification procedures of disperse solid phase extraction (d-SPE) with diatomaceous earth and BondElut cartridge. The ultra-fast chromatographic separation was conducted on a Kinetex C18-XB column (150 mm x 2.1 mm, 2.6 microm) using 0.1% (v/v) formic acid aqueous solution and methanol as mobile phases in gradient elution. The optimized ion transitions were mployed in the mixed-mode of scheduled multiple reaction monitoring (sMRM) -information dependent acquisition (IDA)-enhanced product ion (EPI) scan. Qualification analysis was performed through spectra-matching with on-line lab-built MS/MS library. For quantification stable isotope-labelled analogues of the analytes were used as internal standards. As a result, in porcine liver, kidney and muscle, the nine BBs showed good linearity with all the correlation coefficients (r) more than 0.995 in the range of 0.1-20 microg/L. The limits of quantification (LOQ, S/N > or = 10) were 0.5 kg/kg for all the analytes. The developed method gave average recoveries of 87.5%-111.8% spiked at 0.5, 1.0 and 5.0 microg/kg with the relative standard deviations of 4.0%-12. 5%. The proposed method can be used to screen and confirm the nine BBs in a single run, which makes it effective in surveillance and detection of the BBs residues in porcine tissues.