Critical Evaluation of Different Extraction Procedures for Determination of Organotin Compounds in Mussels

Tadeja Milivojevič Nemanič,a Lucija Zupančič-Kralj,b Radmila Milačič,a Janez Ščančara*

a Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.

University of Ljubljana, Faculty of Chemistry and Chemical Technology, Aškerčeva 5, 1000 Ljubljana, Slovenia

Paper based on a presentation at the 12th International Symposium on Separation Sciences, Lipica, Slovenia,
September 27–29, 2006.

The efficiency of different extraction procedures for the simultaneous determination of organotin compounds in mussels
Mytilus galloprovincialis by gas chromatography – mass spectrometry was critically evaluated. Three different solvents, hydrochloric acid (0.1 mol L–1, 0.5 mol L–1 and 1 mol L–1) in methanol, acetic acid (0.5 mol L–1, 5 mol L–1 and 13 mol L–1) in methanol and a 25% aqueous solution of tetramethylammonium hydroxide, and three different extraction approaches of mechanical shaking, ultrasonic and closed vessel microwave-assisted extraction were used for the extraction of organotin compounds from ERM-CE477 certified mussel tissue reference material. Before determination by GC-MS, extracted organotin species were derivatised with sodium tetraethyl borate and extracted into iso-octane. The results of analyses of ERM-CE477 reference material obtained after the different extraction procedures indicated that 1h of ultrasonic extraction at 50 °C with 0.1 mol L–1 hydrochloric acid in methanol as extraction solvent provided satisfactory recoveries for all organotin compounds certified in this reference material.
The analytical method developed was successfully applied to determination of organotin compounds in mussels
Mytilus galloprovincialis from the Slovenian costal area. Butyltins were found in mussels from all locations investigated. Among them, the highest concentration was of tributyltin, reaching 1100 ng Sn g–1 (dry mass).

Keywords: organotin compounds, mussels, extraction procedures, GC-MS