Comparison of the analysis of beta-blockers by different techniques

In this work we have compared three analytical techniques (ELISA, GC-MS, and LC-MS) for the analysis of 16 beta-blockers: acebutolol, alprenolol, atenolol, betaxolol, bisoprolol, carteolol, labetalol, metipranolol, metoprolol, nadolol, oxprenolol, pindolol, propranolol, sotalol, timolol, and bupranolol. Several sample-preparation methods were optimized for each technique and enabled compounds of interest to be extracted from small urine samples (1-2.5 mL). The results enabled us to assess the possibilities and the sensitivity of each technique for application to doping tests. ELISA, whose selectivity is very poor and sensitivity the lowest one, is, nevertheless, useful as a rapid screening method. GC/MS and LC/MS provide confirmation procedures with the identification and quantification of the beta-blockers with good sensitivity, accuracy, precision. The LC-MS analytical procedure allows the determination of the target analytes in the lower ng/mL range (0.53-2.23 ng/mL). The methodology was applied to the analysis of beta-blockers in different urines.