Hyphenation of Coupled-column Liquid Chromatography and Thermospray Tandem Mass Spectrometry for the Rapid Determination ofβ2-Agonist Residues in Bovine Urine UsingDirect Large-volume Sample Injection.Set-up of Single-residue Methods for Clenbuterol and Salbutamol
✍ Scribed by Hogendoorn, Elbert A.; Zoonen, Piet van; Polettini, Aldo; Montagna, Maria
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 784 KB
- Volume
- 31
- Category
- Article
- ISSN
- 1076-5174
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✦ Synopsis
In a previous work, coupled-column L C (LC/LC) with direct large-volume sample injection for the analysis of fl,-agonists in bovine urine was investigated, in view of its combination with thermospray (TSP) tandem mass spectrometric (MS/MS) detection. In this work, the potential of both conventional L C and LC/LC coupled to TSP-MS/MS for the rapid determination of P,-agonists in bovine urine was evaluated. It was first established that, in order to avoid disturbances in TSP-MS/MS detection due to changes in pressure and flow rate of the mobile phase, LC/LC is preferable to conventional LC. Then, selecting clenbuterol and salbutamol as model compounds for the class of P,-agonists, two single-residue LC/LC/TSP-MS/MS methods were developed, permitting the determination of the analytes in bovine urine samples with a limit of quantification of at least 0.1 ng, ml-', with a sample throughput of 4 h-I. The methods were validated by analysing both spiked urine samples and samples containing clenbuterol or salbutamol residues. Mean recoveries from urine samples spiked with clenbuterol a t levels of 5 and 0.22 ng ml-' were 107% (n = 9, RSD = 7.4%) and 102% (n = 6, RSD = 14%), respectively. A bovine urine sample containing 1.28 ng ml-' clenbuterol residue (previously quantified by GC/MS) was re-analysed by LC/LC/TSP-MS/MS on four different days (n = 3, each day) and yielded a mean concentration of 1.31 ng ml-', with a reproducibility of 8.4%. Bovine urine samples spiked with salbutamol at levels of 10.8 and 0.55 ng ml-' yielded mean recoveries of 101% (n = 3, RSD = 1%) and 89% (n = 3, RSD = 13%), respectively. In bovine urine samples containing salbutamol residues, the concentrations of unconjugated salbutamol were found to be in the range 8-57 ng ml-'.