## 3 Results and Discussion
### Arrow Method Optimization
However, the standard deviation of peak areas appeared to be comparable for the two fiber types (Figure 3). The % RSD on the peak area of each compound was found to be, on average, less than 5.8% for intraday variation (n = 3 replicates measured on three individual days). Naphthalene, 1,2-3-trimethylbenzene, and the n-alkanes larger than C\({}_{12}\) were the only compounds that exhibited intraday variation greater than 10%. Naphthalene exhibited the highest intraday variation with a % RSD of 24.5% on the first of three days of analysis. The lowest intraday variation was for nonane with a% RSD of 0.6% on the first of three days of analysis. The interday variation was slightly higher for each compound than intraday variation. The average of the interday % RSD for all compounds was 9.2%. With the exception of naphthalene and the n-alkanes higher than C\({}_{12}\), the interday variation was always less than 15% RSD. The naphthalene and higher n-alkane data being higher in variation could possibly be attributed to the fact that these compounds had inherently low recoveries on the CWR/PDMS fiber; therefore, variation in the peak area represented a larger proportion of error compared to the average. The tabulated % RSD for intraday and interday variation by each compound can be found in Supplementary Material, Table S1. Figure 3: Comparison data for the carbon wide range (CWR)/polydimethylsiloxane (PDMS) fiber using the volatiles reference mix (VRM) 3 and the saturated alkanes mix (SAM) 3. Error bars represent standard deviation based on n = 3 samples. Fibers in both categories were exposed at room temperature for 5 min and analyzed using the same GC–MS method. Statistical significance (*) was determined using the multiple t-test option, correcting for multiple comparisons using the Holm–Sidak method with \(\alpha=0.05\). Each compound was analyzed individually, without assuming a consistent standard deviation. In this study, some compounds on the wide end of the volatility range were not recovered in significantly higher quantities when comparing SPME Arrow with traditional SPME. Benzene and naphthalene were two compounds that were expected to be recovered in higher quantity by SPME Arrow that were not. A previous study comparing some similar volatiles demonstrated a 2.5 fold increase for benzene and 32 fold increase for naphthalene when comparing SPME Arrow to traditional SPME fibers [18]. However, this previous study compared the two types of fibers for the PDMS sorbent [18] and not for the CWR/PDMS fiber used in the study herein. The PDMS Arrow used in the previous study also had a fiber phase volume of 10.2 \(\upmu\)L [18], whereas the current commercial version of the CWR/PDMS Arrow has a phase volume of 3.8 \(\upmu\)L. This is in contrast to the traditional SPME fiber phase volume of 0.6 \(\upmu\)L used in both studies. The differences in phase coating and phase volume likely contributing to the inconsistency in results compared to the previous report. However, it is important to stress that the responses recovered for these two compounds were still sufficient for detection and quantification, and therefore, this does not represent a significant challenge.