Sampling and Analysis of Butyltin Compounds in Air Using Gas Chromatography and Flame Photometric Detection

Abstract

Organotin compounds are used in a variety of applications including stabilizers, catalysts, antifouling agents, and biocides. Because of the widespread use of organotin compounds in industry and their wide range of toxic effects, it is important to measure worker exposure to specific organotin compounds. Three butyltin compounds were selected for this study—butyltin trichloride, dibutyltin dichloride, and tri-butyltin chloride. These three compounds are typically present in the same work environment; therefore, developing a sampling and analytical method that would allow all three butyltin compounds to be sampled and analyzed simultaneously was desired. A derivatization procedure using sodium tetraethyl-borate (STEB) was selected for study and validation. The validation study demonstrated that sampling using the Occupational Safety and Health Administration (OSHA) Versatile Sampler (OVS) with XAD-2 resin sorbent and analysis using gas chromatography/flame photometric detection (GC/FPD) can be used to evaluate worker exposures to specific butyltin chlorides over the range of 5 to 270 μg/m³ collected at a flowrate of 0.25 L/min over a 3-hour period for a 45-L air sample. Breakthrough studies at 1.5 times the occupational exposure guideline (OEG) of 0.05 mg/m³ showed that samples could be collected at flowrates up to 0.5 L/min for 12 hours without breakthrough. The 14-day storage stability study showed apparent degradation of tributyltin and monobutyltin within a 3-day storage period at both ambient and refrigerated temperatures. There was no further degradation from 3 to 14 days. The stability of dibutyltin was unaffected by storage condition over the 14-day storage study. Subsequent stability studies incorporating a spiking solution control sample were conducted extending the stability study out to 27 days. These data show that all three butyltins were stable at either ambient or refrigerated conditions.

Keywords:

• butyltins
• organotins
• butyltin trichloride
• dibutyltin dichloride
• tributyltin chloride
• sampling and analysis

Notes

^A STEB can spontaneously combust in moist air. Always handle STEB in a glove box flooded with nitrogen. STEB is stored in a dessicator.

^A Precision is expressed as relative standard deviation (RSD) at the 95% confidence interval (% RSD₉₅).