Dozens of research efforts in the previous 10+ years have demonstrated that measurements made using Passive Sampling Devices (PSDs) represent precise and accurate estimates of available organic compounds in aquatic sediment, surface water, and soil.
To overcome the challenges of impractical PSD deployment times in environmental matrices, the PSD research community has adopted the use of Performance Reference Compounds (PRCs) which are loaded into PSDs prior to deployment and used to infer the fraction of steady state attained during the deployment. Traditional PRCs have included compounds with a similar hydrophobicity to the compounds of interest such as stable isotope‐labeled or deuterated forms of the compounds of interest or compounds that are not expected to be absorbed in significant amounts (e.g., rare Polychlorinated Biphenyl (PCB) congeners). Adding these PRCs to PSDs is expensive and requires complicated and time-consuming PRC measurement techniques (e.g., GC or HPLC methods). This presentation will highlight the application of a potentially more time- and cost-efficient suite of compounds for PRCs: visibly-detectable dye compounds. Compared to compounds traditionally used as PRCs, dyes are orders of magnitude less expensive, generally less toxic, can be added and extracted from PSDs in amounts easily measured via Ultraviolent/Visible (UV/VIS) spectroscopy or other visible/colorimetric means, and can be observed in the PSDs with the naked eye. Measurement of dyes in PSDs can be performed with an inexpensive benchtop UV/VIS spectrophotometer via a non-destructive technique in a matter of seconds for a fraction of the cost to measure traditional PRCs. This presentation will detail the approaches and benefits of using dyes as PRCs in a commercially-available PSD, as well as empirical evidence that demonstrates the proof of concept. Our experiments in static and mixed PSD deployments in the laboratory, as well as deployments in the field, indicate the kinetics of dye PRC desorption match those of target analytes (and traditional PRCs) such that dye PRCs can serve as replacements for traditional PRCs. Overall, the use of dye PRCs will allow a much more streamlined and efficient approach for PSD research and development and will also enable more cost-effective analytical chemistry techniques.