Using Receiver Operating Characteristic Curves To Optimize Discovery-Based Software with Comprehensive Two-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometry was written by Reaser, Brooke C.;Wright, Bob W.;Synovec, Robert E.. And the article was included in Analytical Chemistry (Washington, DC, United States) in 2017.Application In Synthesis of 2,5-Dimethylthiophene The following contents are mentioned in the article:
The authors report a quant. approach to optimize implementation of discovery-based software for comprehensive two-dimensional gas chromatog. coupled with time-of-flight mass spectrometry (GC × GC-TOFMS). The software performs a tile-based Fisher ratio (F-ratio) anal. and facilitates a supervised nontargeted anal. based upon the exptl. design to aid in the discovery of analytes with statistically different variances between sample classes. The quant. approach for software optimization uses receiver operating characteristic (ROC) curves. The area under the curve (AUC) for each ROC curve serves as a quant. metric to optimize two key algorithm parameters: the signal-to-noise ratio (S/N) threshold of the data prior to calculating F-ratios at each m/z mass channel and the number of these F-ratios per m/z used to calculate the average F-ratio of a tile. A total of 25 combinations of S/N threshold by number of m/z were studied. Fifty analytes were spiked into a diesel fuel at two concentration levels to produce two sample classes that should in principle produce 50 pos. instances in the ROC curves. The sweet spot for F-ratio anal. is a S/N threshold of 10 coupled with a maximum of the 10 most chem. selective m/z (requiring a min. of 3 m/z), corresponding to an ∼21% improvement in the discrimination of true positives relative to prior studies. This equates to an addnl. 9 true positives being discovered at a false pos. probability of 0.2 and 5 addnl. true positives being found overall. Also, optimization of these software parameters did not depend upon a priori determination of the statistically correct number of pos. instances in the sample classes. The AUC metric appears to be suitable for the evaluation of all data anal. methods that use the proper exptl. design. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8Application In Synthesis of 2,5-Dimethylthiophene).
2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophenes are valuable heterocycles that are widely used in medicines, agrochemicals, and materials science. Due to its aromaticity, thiophenes do not exhibit the same properties as conventional thioethers.Application In Synthesis of 2,5-Dimethylthiophene
Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem