Quantification of 2,4-D on solid-phase exposure sampling media by LC-MS-MS.

Area of Science:

• Environmental Chemistry
• Occupational Health and Safety
• Analytical Chemistry

Background:

• Pesticide exposure, particularly to herbicides like 2,4-dichlorophenoxyacetic acid (2,4-D), is a significant concern for agricultural workers.
• Accurate monitoring of 2,4-D exposure is crucial for assessing health risks and implementing effective safety measures.
• Existing analytical methods for 2,4-D in exposure matrices may have limitations in terms of accuracy, efficiency, or applicability to various sampling media.

Purpose of the Study:

• To develop and validate a robust analytical method for quantifying 2,4-dichlorophenoxyacetic acid (2,4-D) and its amine salts.
• To evaluate the performance of the method using common solid-phase sampling media utilized in occupational exposure assessments.
• To compare the developed method with existing recommended approaches for 2,4-D analysis in similar matrices.

Main Methods:

• Analysis of three solid-phase sampling media (cellulose, polyurethane foam, XAD-2) for 2,4-D and its amine salts.
• Sample extraction using acidified methanol.
• Quantification via liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization.
• Utilization of (13)C 2,4-D as a surrogate and labeled benzoic acid as an internal standard.

Main Results:

• The method demonstrated high average % recovery for (13)C 2,4-D, ranging from 87% to 98% over a three-year study.
• Low % relative standard deviation (7% to 12%) indicated good precision and reproducibility.
• The analytical performance was found to be favorable when compared to the National Institute for Occupational Safety and Health (NIOSH)-recommended method.

Conclusions:

• The validated LC-MS/MS method provides accurate and precise quantification of 2,4-D and its amine salts on cellulose, polyurethane foam, and XAD-2 sampling media.
• This method is suitable for high-volume analysis in occupational exposure studies, such as those involving agricultural workers.
• The developed approach offers a reliable alternative or improvement over current NIOSH-recommended methods for 2,4-D monitoring in personal exposure samples.