Determination of tributyltin and 4-hydroxybutyldibutyltin chlorides in seawater by liquid chromatography with atmospheric pressure chemical ionization-mass spectrometry.
A liquid chromatographic method is described for the simultaneous determination of tributyltin (TBT) and the hydroxylated intermediate 4-hydroxybutyldibutyltin (OHBuDBT). Separation was achieved in reverse phase mode on a cyanopropyl-bonded silica column under a gradient elution. Various organic solvents and additives were tested and the optimum composition of the mobile phase contained methanol, water, formic acid and tropolone as a complexing agent. Butyltin compounds were detected with an ion trap mass spectrometer interfaced to a liquid chromatograph with an atmospheric pressure chemical ionization source (LC-APCI-MS). Identification and fragmentation pattern of OHBuDBT chloride in full scan MS and MS/MS are reported for the first time using LC-APCI-MS. Gas chromatography-mass spectrometry (GC-MS) spectrum of the same compound is also reported for the first time for comparison purpose. This method allowed limits of detection (LOD) of 35 and 26 ng mL(-1) for TBT and OHBuDBT, respectively, based on successive injections of 10 microL of blank seawater extract. A liquid-liquid extraction procedure using n-hexane-ethyl acetate was developed for the simultaneous analysis of TBT and OHBuDBT chlorides in natural seawater and allowed average recoveries from 72 to 96% for the two compounds at three different spiking levels.
Békri
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K
Institut des Sciences de la mer de Rimouski (ISMER), Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, Québec, Canada G5L 3A1. khalidabekri@hotmail.com
Saint-Louis
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R
Pelletier
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E