Dermal wipe sampling method development and validation for semivolatile and nonvolatile flame-retardant compounds TBBPA and TPP for use in occupational exposure assessments

Accurately estimating exposure is critical to assessing the potential health risks of chemicals. Characterizing dermal exposures to semivolatile or nonvolatile compounds in occupational studies can be challenging because of a lack of standardized procedures for dermal wipe sample collection and methods for sample analysis for most industrial chemicals, especially organic compounds. Methodologies are sometimes available in the scientific literature; however, the approaches vary, typically have not been validated, and may not be suitable for application in commercial laboratory settings. This article describes the laboratory development and validation of a method to identify and quantify the semivolatile organic compounds, tetrabromobisphenol A (TBBPA, CAS: 79-94-7) and triphenyl phosphate (TPP, CAS: 115-86-6) in dermal wipe samples and to validate recovery of these chemicals from porcine skin. The analytical method involved extraction of the test compounds on two different wipe media (cotton and polyester-rayon blend) in 100% isopropanol using gas chromatography-mass spectrometry. The results indicate that polyester-rayon wipes were preferable to cotton wipes. Additionally, the dermal wipe sampling method was tested and validated using porcine skin as a surrogate for human skin. This study provides a framework to perform validation of analytical and dermal sample collection methods for other semivolatile and nonvolatile chemicals and provides a baseline method for the development of commercial laboratory methods to evaluate exposure to other chemicals.