Following U.S. EPA 8260B method requirements, the system was tuned using 25 μg/L (ppb) of BFB (4-bromofluorobenzene). There are nine EPA BFB ion ratios that were checked for compliance (Figure 1). 19 compounds were analyzed and examined for detection limits, linearity and throughput. Linearity was checked using a five-level calibration curve in DI water. The range was 0.5-100 μg/L. Ethanol and tert-butyl alcohol were calibrated from 5-200 μg/L. Table 2 displays the list of components analyzed, demonstrates the quantitative precision and linearity of the method. The %RSD (based on relative response factors) for all analytes was within the 15% U.S. EPA 8260B method requirement mandated in environmental labs.
All 19 compounds were identified at all 5 calibration levels and a chromatogram of the 25 μg/L (mid-level calibration) standard is shown in Figure 2. All standards were prepared with appropriate Method 8260B internal standards and surrogates. Inserted into Figure 2 is an extracted ion chromatogram of 5 μg/L of ethanol (the lowest level standard), which demonstrates excellent signal to noise at this concentration. Ethanol is challenging at low concentration levels, when using traditional purge-and-trap technology. Fuel oxygenates such as ethanol are highly soluble in water and difficult to purge. This application illustrates the low detection limits achieved for these difficult components using the new headspace-trap technology.
The TurboMatrix Headspace Trap