Abstract

This research introduces a new analytical methodology for measuring chemical activity of nonpolar (semi)volatile organic compounds in different sample matrices using automated solid-phase microextraction (SPME). The chemical activity of an analyte is known to determine its equilibrium concentration in the SPME fiber coating. On this basis, SPME was utilized for the analytical determination of chemical activity, fugacity, and freely dissolved concentration using these steps: (1) a sample is brought into a vial, (2) the SPME fiber is introduced into the headspace and equilibrated with the sample, (3) the SPME fiber is injected into the GC for thermal desorption and analysis, and (4) the method is calibrated by SPME above partitioning standards in methanol. Model substances were BTEX, naphthalene, and alkanes, which were measured in a variety of sample types: liquid polydimethylsiloxane (PDMS), wood, soil, and nonaqueous phase liquid (NAPL). Variable sample types (i.e., matrices) had no influence on sampling kinetics because diffusion through the headspace was rate limiting for the overall sampling process. Sampling time was 30 min, and relative standard deviations were generally below 5% for homogeneous solutions and somewhat higher for soil and NAPL. This type of activity measurement is fast, reliable, almost solvent free, and applicable for mixed-media sampling.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.