APPLIED ORGANOMETALLICCHEMISTRY, VOL. zyxwvu 8,577-585 zyxwvut (1994) zyxwv Validation of the Analysis of Organotin Compounds in Biological Tissues Using Alkylation and Gas Chromatography Joan A. Stab,*t Udo A. Th. BrinkmanS and Wim P. Cofino * Institute for Environmental Studies, Free University, De Boelelaan 1115, 1081 HV Amsterdam, The Netherlands, and t Department of Analytical Chemistry, Free University, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands Several critical steps in the analytical procedure for organotin compounds in the environment are identified in this paper and solutions are sug- gested. In particular, an improved procedure for quenching excess Grignard reagent is described. After insight into the nature of losses was obtained, the use of internal standards made it possible to reduce further the method variability. The systematic optimization of the analytical pro- cedure resulted in a well investigated and robust method for analysis of organotin compounds in zebra mussel samples. Organotin compounds (OTs) which enter the environment as a result of their use zyxwvut as biocides and their degradation pro- ducts are regularly found in environmental sam- ples. Many different analytical techniques are cur- rently being used,' but little is known about their accuracy and precision. Keywords: Organotin, gas chromatography, mass spectrometry, atomic emission, validation, environmental analysis INTRODUCTION This presents a considerable challenge for several reasons. The methods have to be very sensitive and selective to be able to detect concentrations at the low environmental target values issued for triphenyltin (TPT) and tributyltin (TBT). In most European countries environmental quality targets of 10 ng 1-' for water samples and 1-2 n g-' for and mono-OTs no legal environmental threshold sediment samples are now implemented. 8 For di- t To whom correspondence should be addressed. Present address: Dune Water Works, P.O. Box 34, 2270 AA Voorburg, The Netherlands. limits have yet been set, but in view of their toxicity and presence in the environment it is desirable to incorporate them in new analytical techniques. For reasons of efficiency it is desired to extract both non-polar tri-OTs and polar mono- and di- OTs simultaneously. These compounds span a range of hydrophobicity. Techniques employing apolar solvents will extract the polar OTs only to a limited extent.' Aggressive digestion tech- niques, such as those used in heavy-metal analy- sis, cannot be used, as OTs are not stable under these conditions. Therefore, a non-destructive extraction technique that still allows good extrac- tion of polar compounds has to be used. Extraction schemes employing acetic acid, metha- nol or diethyl ether, combined with complexing agents, are often For separation, GC has a high separation capa- bility. A derivatization step is required, however, because the high polarity of di- and mono-OTs prevents direct analysis by capillary GC. Analysis by high-performance liquid chromatography (HPLC) is not a viable solution as the great difference in polarity makes chromatography in a single run of non-derivatized mono-, di- and tri- OTs difficult. Moreover sensitive detection of OTs after HPLC is not easily accomplished. For GC, sensitive and selective detectors are nowa- days available. In this study an atomic emission detector (AED) and two types of mass- spectrometric detectors (a quadrupole and an ion trap) were used successfully. For the assessment of accuracy of the analysis of all OTs found in biological matrices, no certi- fied reference materials exist yet. In this study, validation was accomplished by a thorough investigation of the technique. An assessment of the precision of the method was obtained by determining recoveries of spikes and by compar- ing two different extraction procedures, CCC 0268-2605/94/070577-09 @ 1994 by John Wiley & Sons, Ltd. zyxwvutsr Received 5 April 1994 Accepted 14 June 1994