## 7 Applications
### Environmental Analysis
This geometry uses a tape-like PDMS thin film as a sampling device, providing an easy method of application for the non-invasive sampling of environmental and biological [61] matrices, recently being demonstrated by [PERSON] et al. [33] to be suitable for the analysis of herbivory-induced plant volatiles. While viewed currently as a passive sampling device, similar technology could be implemented in the development of new, more convenient TF-SPME devices. During the development of particle-loaded TF-SPME devices, in this instance DVB particles in PDMS, [PERSON] et al. demonstrated the greatly enhanced sensitivity TF-SPME offers in trace air sampling and monitoring [36]. This particle loaded TF-SPME device was able to achieve extraction of a wide range of analytes with differing volatilities at high capacity. Furthermore, the study quantitatively samples benzene as a model analyte, a known carcinogen that is found commonly in fuels and smoking devices or from polluted air near a high-traffic road. Other more recent studies have confirmed the use of TF-SPME as a validated onsite sampling tool by its use in the analysis of biocides and UV blockers in sunscreen found in rivers, utilizing HLB/PAN and octadecyl (C\({}_{18}\))/PAN TF-SPME devices [54]. Moreover, the efficacy of TF-SPME for the analysis of trace and ultra-trace level analysis in environmental matrices has been repeatedly tested and validated since its inception. In more recent times, since the development of carbon mesh-based TF-SPME devices, TF-SPME has been proven to be even more of a convenient sampling tool for onsite analysis due to the structural robustness of the device and its ease of introduction to portable instrumentation [19]. Since then, an interlaboratory study comparing these newly improved TF-SPME devices (DVB/PDMS on carbon mesh) to EPA-validated LLE methods demonstrated the efficacy of TF-SPME as a greener and more sensitive technique for the routine analysis of pesticides in water [55]. This comparative study by [PERSON] and colleagues compared the suitability of different TF-SPME approaches to LLE. These approaches comprised of an in-bottle TF-SPME method using benchtop GC/MS, an onsite drill-assisted sampling that later used benchtop GC/MS and a procedure that used the same drill-assisted sampling as the previous but instead used a portable GC/MS to achieve both onsite sampling and onsite analysis. Results demonstrated (Table 2) the robustness of all TF-SPME-based methods, with the onsite extraction and analysis being the most environmentally friendly of all methods in the study [55]. In a similar fashion, the performance of TF-SPME has further been compared to other extraction methods, namely fiber SPME and SPE, in the analysis of harmful coal frothing agents that have been reportedly released into environmental waters and, by consequence, contaminated drinking water supplies. This study, the first to use a Car/PDMS TF-SPME device with carbon mesh support, was able to reliably extract multiple components of the coal frothing agent, crude (4-methylcyclohexyl)methanol (MCHM), along with a tentative metabolite with minimal sample manipulation. Results again showed TF-SPME devices to be more efficient at trace-level analysis than other methods (Table 2) [8]. Furthermore, with the development of novel HLB TF-SPME devices, [PERSON] and colleagues demonstrated the wide range of analytes that can be extracted by the analysis of chlorination byproducts in residential hot tubs [30]. Applications of TF-SPME devices using other modes of desorption have also been applied in the environmental sector. Recently, [PERSON] and colleagues have utilized graphene TF-SPME devices coupled with chelating agents to sample various different metals in aqueous samples before analysis using total reflection X-ray fluorescence (TXRF) [28]. Similar methods have also employed similar TF-SPME-TXRF protocols with the use of nanomaterial TF-SPME devices [27]. In recent years, nanomaterial-based TF-SPME devices have been successfully applied to TD [63]. [PERSON] et al.