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

Objectives: This study aimed to develop a personal exposure measurement method that concurrently determines both the inhalable fraction and vapor concentration of tri-n-butyl phosphate (TBP). Methods: A personal sampler, the IFV Pro, equipped with a glass fiber filter (GFF) and a Chromosorb 106 adsorption tube was utilized. 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%, while the desorption efficiency from Chromosorb 106 was between 98% and 102%. The retention efficiencies for TBP were 0% (not quantitative, <0.68 μg/sample)–88% on the GFF and 7%-95% on Chromosorb 106, culminating in a total retention efficiency of 95%-98%. Relative standard deviations, 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.