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Lab Methods

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Dye Content

  • Method ASTM D6258
  • Repeatability 0.1847(x)0.5
  • Reproducibility 0.7652(x)0.5
  • Blending linear
  • Additive Correction Yes

This test method covers the procedure for determining the concentration of dye Solvent Red
164 in commercially available diesel and burner fuels using visible spectroscopy.

The concentration ranges specified for the calibration standards are established in response to the Internal Revenue Service dyeing requirements which state that tax-exempt diesel fuel satisfies the dyeing requirement only if it contains the dye Solvent Red 164 (and no other dye) at a concentration spectrally equivalent to 3.9 lb of the solid dye standard Solvent Red 26 per thousand bbl (11.1 mg/L) of diesel fuel.

This method uses a spectrophotometer to identify the quantity of dye in the diesel sample. First a standard is placed in the unit to confirm it is reading correctly. After a small vial of sample is placed and the final reading is given by the unit to confirm the product meets spec for the dye content. The dye is important to the IRS for taxation purposes. Dyed fuel is for off road use only as it is not taxed like on road fuel is.