TY - JOUR

T1 - Investigating Potential Limitations of Current Diffusive Gradients in Thin Films (DGT) Samplers for Measuring Organic Chemicals

AU - Wang, Runmei

AU - Zou, Yitao

AU - Luo, Jun

AU - Jones, Kevin C.

AU - Zhang, Hao

N1 - This document is the Accepted Manuscript version of a Published Work that appeared in final form in Analytical Chemistry, copyright ©2019 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.analchem.9b02571

PY - 2019/10/15

Y1 - 2019/10/15

N2 - The diffusive gradients in thin films (DGT) passive sampler has emerged as a powerful tool for measuring in situ concentrations of organic contaminants in waters with appropriate spatial and temporal resolution at low cost. This study addresses the property range of compounds which can be routinely sampled with the present design of DGT device. Sorption experiments and DGT deployment with 9 model chemicals [organophosphate esters with a wide range of log KOW (0.8–9.5), molecular weight (182–435 Da)] and different functional groups showed compounds with high hydrophobicity and aromatic rings are prone to retention on membrane filters, which slows the supply of chemical to the binding resin of the sampler. The current DGT sampler (PTFE membrane filter, agarose gel diffusion layer, and HLB binding layer) is potentially reliable for measuring hydrophilic [log KOW (0.8–2.6)] and nonaromatic-ring chemicals. For compounds of higher values of KOW or with aromatic rings, knowledge of the lag phase is necessary to optimize sampling times to avoid biasing subsequent laboratory analyses. A standard procedure is used to measure lag times (from minutes to days) by exposing a series of DGT samplers in waters until linear mass accumulation in samplers is achieved. We discuss how monitoring of a wide array of organic contaminants across classes should be possible in the future with a range of validated new DGT devices, optimized for the choice of membrane filter, diffusive material, and binding resin.

AB - The diffusive gradients in thin films (DGT) passive sampler has emerged as a powerful tool for measuring in situ concentrations of organic contaminants in waters with appropriate spatial and temporal resolution at low cost. This study addresses the property range of compounds which can be routinely sampled with the present design of DGT device. Sorption experiments and DGT deployment with 9 model chemicals [organophosphate esters with a wide range of log KOW (0.8–9.5), molecular weight (182–435 Da)] and different functional groups showed compounds with high hydrophobicity and aromatic rings are prone to retention on membrane filters, which slows the supply of chemical to the binding resin of the sampler. The current DGT sampler (PTFE membrane filter, agarose gel diffusion layer, and HLB binding layer) is potentially reliable for measuring hydrophilic [log KOW (0.8–2.6)] and nonaromatic-ring chemicals. For compounds of higher values of KOW or with aromatic rings, knowledge of the lag phase is necessary to optimize sampling times to avoid biasing subsequent laboratory analyses. A standard procedure is used to measure lag times (from minutes to days) by exposing a series of DGT samplers in waters until linear mass accumulation in samplers is achieved. We discuss how monitoring of a wide array of organic contaminants across classes should be possible in the future with a range of validated new DGT devices, optimized for the choice of membrane filter, diffusive material, and binding resin.

U2 - 10.1021/acs.analchem.9b02571

DO - 10.1021/acs.analchem.9b02571

M3 - Journal article

VL - 91

SP - 12835

EP - 12843

JO - Analytical Chemistry

JF - Analytical Chemistry

SN - 0003-2700

IS - 20

ER -