Identification of source of a marine oil-spill using geochemical and chemometric techniques.

The current work aimed to identify the source of an oil spill off the coast of Maranhão, Brazil, in September 2005 and effect a preliminary geochemical survey of this environment. A combination of bulk analytical parameters, such as carbon isotope (δ(13)C) and Ni/V ratios, and conventional fingerprinting methods (High Resolution Gas Chromatography and Mass Spectrometry) were used. The use of bulk methods greatly speeded source identification for this relatively unaltered spill: identification of the likely source was possible at this stage. Subsequent fingerprinting of biomarker distributions supported source assignment, pointing to a non-Brazilian oil. Steranes proved the most useful biomarkers for sample correlation in this work. Distribution patterns of environmentally more resilient compound types, such as certain aromatic structures, proved inconclusive for correlation, probably in view of their presence in the background.

Diagnostic evidence for the presence of beta-agonists using two consecutive derivatization procedures and gas chromatography-mass spectrometric analysis.

A GC-MS procedure for the detection of different beta-agonists in urine samples based on two consecutive derivatization steps is described. The derivatization procedure is based on the consecutive formation of cyclic methylboronate derivatives followed by a second derivatization step with MSTFA on the same extract, forming TMS derivatives. Injections in the GC-MS system may be carried out after each one of the derivatization steps, obtaining enough information for unambiguous identification. Limits of detection for the two derivatization steps ranged from 0.5 to 5 ng/ml. This procedure was tested with the beta-agonists bambuterol, clenbuterol, fenoterol, formoterol, salbutamol, salmeterol, alpha-hydroxy-salmeterol and terbutaline.