# A method for determining workers’ exposure concentration to airborne nitrilotriacetic acid

## TL;DR

This paper introduces a reliable method to measure workers' exposure to airborne nitrilotriacetic acid using a glass-fiber filter and gas chromatography-mass spectrometry.

## Contribution

The study presents a novel method for collecting and analyzing airborne NTA using a glass-fiber filter and gas chromatograph–mass spectrometer.

## Key findings

- The retention efficiency of NTA on the glass-fiber filter was 94%-101%.
- NTA samples were stable at 4°C for at least 7 days.

## Abstract

This study aimed to establish a method to determine workers’ exposure concentrations to airborne nitrilotriacetic acid (NTA).

The sampler used an air sampling cassette containing a glass-fiber filter (GFF). After sampling, NTA extracted from the GFF using ultrapure water was derivatized using a boron trifluoride-methanol complex methanol solution and analyzed using a gas chromatograph–mass spectrometer. The developed method was validated for the following parameters: retention efficiency, storage stability, method quantitation limit, and reproducibility.

The retention efficiency for NTA on the GFF was 94%-101%, with the relative SD indicating the overall reproducibility (range 0.9%-2.4%). NTA on the GFF was stable at 4°C for at least 7 days. The method quantitation limit was 4.8 μg per sample.

The developed method will be useful for risk assessments because it can determine workers’ exposure concentrations to NTA ranging from 0.02 to 4 mg/m3 in a 240 L sampling volume; the quantitation limit is 4.8 μg per sample.

Key points

What is already known on this topic: Nitrilotriacetic acid (NTA) is used in a wide range of industrial applications. The Deutsche Forschungsgemeinschaft has proposed occupational exposure limits based on the toxicity of NTA, but no method existed to measure airborne NTA exposure concentrations for workers.

What this study adds: This study presents a method for collecting NTA using a glass-fiber filter and analyzing it using a gas chromatograph–mass spectrometer. The developed method can measure workers’ exposure concentrations to NTA ranging from 0.02 to 4 mg/m3 in a 4-hour sampling period.

How this study might affect research, practice, or policy: The established approach can estimate workers’ NTA exposure levels and subsequently help prevent their exposure to NTA.