Characterization of alkyl‐ and aryl‐tins by means of electrospray mass spectrometry

Abstract

The organotins, mainly the trialkyltins and triphenyltins, have a widespread application as fungicides, anti-fouling coatings for porous and non-porous surfaces, herbicides, insecticides, and generic biocides. Traditional environmental monitoring methods can only give limited speciation of the organometallics. The speciation of a wide variety of alkyl-and aryl-tin isomers using liquid chromatography coupled with mass spectrometry under positive-ionization conditions is reported. Detection of the organotins was enhanced by the use of acetic acid in the methanol mobile phase. There were unexpected high-mass ions with multiple tin-isotope patterns present in many of the spectra. These high-mass species were possibly attributable to tin polymers, whose presence has been observed by others using X-ray methods.The use of alkyl-and aryl-tins in the environment has increased dramatically over the last few decades. The US Environmental Protection Agency (U.S. EPA), through the Office of Research and Development (ORD) and its analytical methods development program at the Environmental Monitoring Systems Laboratory at Las Vegas (EMSL-LV) is conducting a program to understand the properties of organometallics, including organotin compounds. The objective is to provide effective monitoring, measurement, or speciation methods. Prevailing methodology only analyzes the total amount of tin. It is important to be able to differentiate the differing organic functional groups, as they can impart various levels of toxicity to different organisms.' The ability to monitor and speciate the organotins at low levels has become a serious environmental need., The organotins, mainly the trialkyltins and triphenyltins, are widely applied as fungicides, anti-fouling coatings for porous and non-porous surfaces, herbicides, insecticides, and generic biocides.' The di-and mono-organotin compounds are mainly used in non-pesticidal industrial applications, for example as stabilizers for polyvinyl chloride and as precursors for forming SnO, films on glass and homogeneous catalyst^.^ It is estimated that the world-wide pesticidal use of the triorganotin compounds is 8000 metric tons, and is exceeded by the non-pesticidal applications of the di-and mono-organotins, at 27 000 metric tons annually. Traditional environmental monitoring methods (e.g., derivatization with gas chromatography/flame photometry4 and hydride formation with atomic absorption spectrometry') can only give limited speciation of the organometallics. Other researchers have used liquid chromatography/ionspray mass spectrometry (LC/IS-MS) to characterize the alkyl-and aryl-tin species6 and to quantify tributyltin in a sediment reference materiaL7 Our research efforts have concentrated on the speciation of a wide variety of alkyl-and aryl-tin congeners (Table 1) by liquid chromatography coupled to electrospray mass spectrometry (LC/ES-MS) under positive-ionization conditions. *Author to whom correspondence should be addressed. EXPERIMENTALElectrospray mass spectrometry. A Vestec (Hous...

Tandem mass spectrometric analysis of distinct fragmentation patterns to [M+Na]/z and [M+H]/z of dendritic Al(III) and Zn(II) quinolates

“…The electrospray ionization mass spectrometry (ESI‐MS) method allows ionization/desorption of non‐volatile analytes into the gas phase, to be detected by mass spectrometry 8. The ability of ESI to produce ions from aqueous or organic solutions with high sensitivity makes it a complementary tool for examining the speciation of dissolved metals9 and organometallic species 10. ESI‐MS has been used to monitor the synthesis of dendrimers11 and polyamide/peptide conjugates 12.…”

Speciation and detection of organotins from PVC pipe by micro‐liquid chromatography–electrospray–ion trap mass spectrometry

“…The presence of tin(II) ions is not unexpected and has been seen by one of the authors in previous work, and other researchers have shown that charge reduction of metal ions can occur in the electrospray source. 21,22 The other butyltins, TBT and MBT, were also screened for. TBT was not present above the limit of detection (LOD) of this method (LOD = 780 pg).…”

Determination of organotins in water by micro liquid chromatography-electrospray/ion trap mass spectrometry

“…Newer methodologies to overcome the use of derivatization and complexation include the use of capillary electrophoresis (CE) with indirect ultraviolet 18 and direct (UV) 19 absorbance detection, ICP MS with micellar liquid chromatography, 20 HPLC with ion-exchange chromatography coupled to ICP MS 21 and electrospray-mass spectrometry (ES-MS) (see Ref. 22 , and references cited therein). Although ICP MS is a very sensitive mass-spectrometric method, still it is not totally definitive.…”

“…The presence of Sn(II) ions is not unexpected and was seen by one of the authors in previous work the ion at m/z. 22 Also, 413 (Fig. 3b) is a background ion, attributable to ion clusters formed from the mobile-phase constituents.…”