The objective of this research was to determine the limit of detection (LOD) and limit of quantification (LOQ) at split ratios of 50:1, 25:1, and 10:1 when running sensitivity analyses under typical conditions by a student with limited prior experience. GC-MS (Shimadzu Model: QP2010SE) and GC-FID/ECD (Thermo Fisher Model: Trace 1310) were used and compared. Standard solutions of octane in methanol were prepared with a range from 10,000 ppm to 0.0001 ppt, diluting as necessary to reach the detection limit of each instrument and create a working curve. The GC-MS has shown to be less sensitive to octane when compared to the GC-FID. The lowest detectable standard on GC-MS was 100 ppt run with a split ratio of 10:1, while the GC-FID was able to detect 0.0001 ppt with the same split ratio. As the split ratio decreased, the peak area on GC-FID and the total ion count (TIC) on GC-MS were consistently higher for both instruments, achieving a lower LOD for the lower split ratio. This was an expected result as more analyte was injected onto the column. Further testing on both instruments will be done to determine the calculated LOD and LOQ for each split ratio. Since the GS-MS instrument is 15-years old, while the GC-ECD is new, a halogenated compound will be run to determine the LOD and LOQ for the two instruments, with the possible implication of how sensitivity may decrease over time due to the degradation of the radioactive film containing <sup>63</sup>Ni.

Sensitivity comparison of GC-MS and GC-FID/ECD

253rd National Meeting (2017)

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