Solid-Phase Reactivity-Directed Microextraction Analysis for Identifying Unknown Toxic Disinfection Byproducts.

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Toxicology

Background:

• Many disinfection byproducts (DBPs) remain unidentified, posing potential toxicological risks in drinking water.
• Current methods for DBP identification are limited in scope and efficiency.
• Understanding the full spectrum of DBPs is crucial for public health risk assessment.

Purpose of the Study:

• To develop a novel reactivity-directed analysis method for identifying unknown toxic DBPs.
• To enhance the detection and characterization of DBPs using a biomimetic approach.
• To assess the toxicity and health risks associated with newly identified DBPs.

Main Methods:

• Development of a solid-phase microextraction (SPME) fiber coated with 4-mercaptophenylboronic acid (MPA) via cis-diol bonding.
• Utilizing thiol-Michael addition reactions for capturing potentially toxic DBPs and pH-responsive cleavage for adduct release.
• Employing boron isotope patterns and MPA-derived fragments for adduct prioritization and identification.

Main Results:

• The heterogeneous SPME method demonstrated superior performance compared to traditional homogeneous approaches.
• Analysis of chlorinated simulated source water identified 30 DBP-MPA adducts.
• Seven DBPs were identified, including one known (chloroacetic acid) and six novel DBPs, with two confirmed using authentic standards.

Conclusions:

• The developed SPME reactivity-directed method is effective for identifying unknown toxic DBPs.
• Six previously unknown toxic DBPs were discovered, with predicted toxicity contributions to disinfected water.
• This study advances qualitative methodology for DBP identification, crucial for water safety and risk assessment.