A method for simultaneously determining both the inhalable fraction and vapor concentration to assess worker exposure to tri- <i>n</i> -butyl phosphate

A personal sampler, the IFV Pro, equipped with a glass-fiber filter (GFF) and a Chromosorb 106 adsorption tube was used. Postsampling, TBP was extracted or desorbed separately from the GFF and Chromosorb 106 using dichloromethane containing tri-n-amyl phosphate as an internal standard. The solutions obtained were analyzed via gas chromatography with a flame ionization detector. The evaluation parameters for validating the method included extraction efficiency, desorption efficiency, retention efficiency, storage stability, method quantitation limit, and reproducibility. Results The extraction efficiency of TBP from the GFF ranged from 97% to 100%, whereas the desorption efficiency from Chromosorb 106 was between 98% and 102%. The retention efficiencies for TBP were 0% (not quantitative, <0.68 μg/sample) to 88% on the GFF, and 7% to 95% on Chromosorb 106, culminating in a total retention efficiency of 95%-98%. Relative SDs, indicative of reproducibility, ranged from 0.8% to 6.9%. Both TBP on the GFF and in the Chromosorb 106 tube maintained stability under refrigeration at 4°C for at least 7 days. The method quantitation limit was established at 6.00 μg/sample. Conclusions A method was established to measure both the inhalable fraction and vapor concentration of TBP across an air concentration range of 0.05 to 10 mg/m3. This method is potentially valuable for assessing TBP exposure levels in workers.