Novel Method for in Situ Monitoring of Organophosphorus Flame Retardants in Waters

Abstract

Widespread use of organophosphorus flame retardants (OPFRs) and their ubiquity in water results in the need for a robust and reliable monitoring technique to better understand their fate and environmental impact. In situ passive sampling using the diffusive gradients in thin-films (DGT) technique provides time-integrated data and is developed for measuring OPFRs here. Ultrasonic extraction of binding gels in methanol provided reliable recoveries for all tested OPFRs. Diffusion coefficients of TCEP, TCPP, TDCPP, TPrP, TBP, and TBEP in the agarose diffusive gel (25 °C) were obtained. The capacity of an HLB binding gel for OPFRs was >115 μg per disc, and the binding performance did not deteriorate with time up to 131 days. DGT performance is independent of typical environmental ranges of pH (3.12-9.71), ionic strength (0.1-500 mmol L), and dissolved organic matter (0-20 mg L), and also of diffusive layer thickness (0.64-2.14 mm) and deployment time (3-168 h). Negligible competition effects between OPFRs was found. DGT-measured concentrations of OPFRs in a wastewater treatment plant (WWTP) effluent (12-16 days) were comparable to those obtained by grab sampling, further verifying DGT's reliability for measuring OPFRs in waters.

In Situ Catchment Scale Sampling of Emerging Contaminants Using Diffusive Gradients in Thin Films (DGT) and Traditional Grab Sampling: A Case Study of the River Thames, UK

“…52 The DGT measurement of the studied OPEs is independent of pH 3.1-9.7. 24,53 The above literature also showed the DGT measurement of these target chemicals is independent of ionic strength (0.001-0.1 M) and dissolved organic matter (0−20 mg/L). Overall, DGT measurement of these target chemicals in the rivers of the Thames catchment is not expected to be affected by pH (pH = 7.9±0.2 in sampling periods), ionic strength (average 0.01 M) and dissolved organic matter (DOM = 7.2±2.6 mg/L in sampling periods) (pH and DOM measured and provided by CEH).…”

“…They are important ECs in river systems with well-developed DGT methods 23 and can be monitored using one DGT configuration (see sampler details later). 24,26,27,[48][49][50] Thirteen target chemicals were selected across EC types, as follows: S3 and their structures in Figure S3. Isotope-labelled chemicals were used as surrogate internal standards (SIS): SMX-d4, CAF-13C3, MEP-13C6, PRP-13C6, BUP-13C6, PHBA-d4 and E3-d2.…”

“…At the time of writing, DGT has been developed and validated for over 150 organic compounds, including pharmaceuticals, HPCPs, flame retardants, estrogens, pesticides, drugs, etc. [24][25][26][27][28] Until now, research into DGT for organics has mainly focused on laboratory development and calibration, 20,22,29,30 with a few field evaluations conducted mostly in raw or treated wastewaters. 26,31,32 Applying DGT to rivers at a catchment scale is necessary to test and demonstrate its reliability and challenges in a dynamic water system, with different environmental conditions.…”

A new method based on diffusive gradients in thin films for in situ monitoring microcystin-LR in waters

“…Zou et al . 31 also used HLB in DGT to detect organo-phosphorus flame retardants. The HLB material is a well-known and effective adsorbing material for several organics, including MCs 32 .…”

Investigating Potential Limitations of Current Diffusive Gradients in Thin Films (DGT) Samplers for Measuring Organic Chemicals

“…In contrast, research and development of DGT for organic chemicals only started in 2012, but it has already attracted considerable interest and is developing rapidly . To date, sampler development and testing of 136 organic compounds has been reported in the literature (a few from personal communication), with more being conducted. − Compound classes include pharmaceuticals and personal care products, illicit drugs, endocrine-disrupting chemicals and pesticides, etc. Table S1 summarizes these publications.…”