I say Organotins; you say… wait organotins by GC-MS/MS? I said the same thing. In fact GC-MS/MS is a great way to test for organotins. Now the next question is why to test for organotins. There are a few reasons. First there is the regulatory reason. This is a good one. Countries must meet their own regulatory requirements for keeping their coasts and other areas safe. Second is economic as it relates to food contamination. If the waters you are fishing in waters contaminated with organotins it stands to reason that the food will be too. The third reason is, well, because we honestly should not be contaminating the environment with chemicals we know cause harm to living things. It’s one thing to do it accidently but if you know there is a problem it’s time to fix it.
The European Union Water Framework Directive seeks to lower detection and reporting limits for many contaminants. One class of these compounds is Organotins. These include mono-, di-, tri-, tetrabutyl- and tiphenyl tin compounds. Tributyltin compounds are considered the most hazardous, and several studies have shown the effect on shell malformation of oysters, imposex of marine snails and reduced resistance to infections. Exposure to these compounds has been reported to cause acute kidney and central nervous disorders in humans. Organotins are used widely in industry for a variety of applications, including as antifouling agents on underwater structures for both tributyl- and triphenyltin; triphenyltin is used as a fungicide in crop protection. Mono- and dibutyltin have uses as stabilizers in plastics and catalysts in soft foam production.
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Concentration levels of organotins in seawater are in the ppb to ppt range. Higher concentrations are found in sediment and biological samples. Organotins are lipophilic and get absorbed into adipose tissue. They can also be absorbed into particulate matter. The toxicity of these compounds at low concentrations drives the requirement for accurate and sensitive analytical methods for their detection, quantitation and research for less-toxic replacements. The method described in this paper uses theTSQ Quantum XLS GC-MS/MS systems to provide detection and quantitation limits that go below regulatory requirements with the use of t-SRM.
Sample preparation is pretty simple but very important for this, and any, analysis. It is described in the application note and in the references. The instrument method was relatively simple too. The GC injection and oven parameters are listed in the application note. This method did benefit from a guard column. T-SRM allowed the instrument to determine the best length of time to monitor specific ion transitions so you do not have to think about it. The TSQ Quantum XLS parameters for all of the organotins are listed in a table in the application note. The method demonstrates detection and quantitation levels to 0.05 ng/L, exceeding the EU Directive’s annual allowable average of 0.2 ng/L.
Downlaod the application note here; Organotins in Seawater