16 CFR Part 306; Automotive Fuel Ratings, Certification and Posting; Project No. R811005
The FTC is considering allowing NIR spectroscopy methods to be used for measuring critical fuel properties. This is an excellent idea. To be fair please broaden the spectroscopic methods to include any spectroscopic method that can demonstrate good correlation with existing Knock Engine methods. Specifically, Raman spectrscopy a form of vibrational spectroscopy that affords excellent resolution and ease of use, when compared with existing NIR spectroscopy. Many of the ASTM methods such as D6122 were written long ago when spectroscopic methods only included, NIR and perhaps MIR-IR. Raman is rapidly replacing these older spectroscopic methods as Best Practices for on-line gasoline monitoring. To keep the FTC's regulations up to date, including newer spectroscopic methods now, will eliminate having to go back and adjust the regulations later on. Raman spectroscopy affords many advantages when compared to conventional NIR spectroscopy: 1. No sample conditioning is required, which means the end user does not have to install considerable expensive sample conditioning equipment, saving money and reducing maintenance. 2. Raman is easier to model due to its better spectral resolution, which means the end user requires fewer samples for model building, requires fewer chemometric models, and the models tend to be more robust, i.e. they last longer before they need to be update. 3. Raman can measure more key properties, in addition to just Octane, Raman spectroscopy can measure, RVP, aromatics, benzene, total olefins, total sulfur, etc. many properties that are critical for fuel monitoring. Many of these properties, such as RVP, Total sulfur, and benzene, are not easily measured using conventional NIR spectroscopic methods. Thank you for your consideration.