Organophosphate esters by GC-MS: An optimized method for aquatic risk assessment

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Ecotoxicology

Background:

• Organophosphate esters (OPEs) are widespread contaminants in surface waters.
• OPEs are known neurotoxicants, endocrine disruptors, and can harm aquatic organism reproduction and development.

Purpose of the Study:

• To develop and validate an analytical method for accurate OPE quantification in river water.
• To ensure the method's detection limits are below predicted no-effect concentrations for aquatic risk assessment.

Main Methods:

• Solid phase extraction (SPE) coupled with gas chromatography-mass spectrometry (GC-MS).
• Multivariate optimization for large volume injection using a Programmable Temperature Vaporization (PTV) inlet.
• Matrix effect compensation using extraction-blank-matched calibration and isotopically labeled standards.

Main Results:

• Method quantification limits ranged from 0.009 to 0.11 µg/L, suitable for risk assessment.
• Eight of ten target OPEs were quantified in river water samples from Sao Paulo State, Brazil.
• Tris(2-chloroisopropyl) phosphate and tris(phenyl) phosphate were the most frequently detected OPEs.

Conclusions:

• The developed GC-MS method is effective for analyzing OPEs in environmental water samples.
• The method's sensitivity meets the requirements for ecological risk assessment of OPE contamination.
• The study highlights the prevalence of specific OPEs in Brazilian rivers, informing environmental monitoring strategies.