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

## TL;DR

This paper introduces a new method to measure both the inhalable and vapor forms of tri-n-butyl phosphate in workplace air to better assess worker exposure.

## Contribution

A novel personal sampling method that simultaneously quantifies both the inhalable fraction and vapor concentration of tri-n-butyl phosphate.

## Key findings

- The method achieved high extraction and desorption efficiencies for TBP from the sampling media.
- The developed method has a quantitation limit of 6.00 μg/sample and good reproducibility.
- The method enables accurate exposure assessment of TBP in the range of 0.05 to 10 mg/m³.

## Abstract

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 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.

Key points:

What is already known on this topic: Tri-n-butyl phosphate (TBP) is used in various industrial applications. Owing to its physical properties, TBP can exist both as an aerosol and a vapor in workplace environments. Despite this, there has been no adequate method to simultaneously quantify both states to evaluate worker exposure to TBP.
What this study adds: This research introduces a method using an IFV Pro Sampler equipped with a glass-fiber filter and a Chromosorb 106 adsorption tube. The method enables the measurement of personal exposure concentrations of TBP ranging from 0.05 to 10 mg/m3.
How this study might affect research, practice, or policy: The developed method provides a means to more accurately estimate TBP exposure levels among workers, potentially influencing occupational safety standards and health policies.

What is already known on this topic: Tri-n-butyl phosphate (TBP) is used in various industrial applications. Owing to its physical properties, TBP can exist both as an aerosol and a vapor in workplace environments. Despite this, there has been no adequate method to simultaneously quantify both states to evaluate worker exposure to TBP.

What this study adds: This research introduces a method using an IFV Pro Sampler equipped with a glass-fiber filter and a Chromosorb 106 adsorption tube. The method enables the measurement of personal exposure concentrations of TBP ranging from 0.05 to 10 mg/m3.

How this study might affect research, practice, or policy: The developed method provides a means to more accurately estimate TBP exposure levels among workers, potentially influencing occupational safety standards and health policies.