To assist refiners in determining D86 boiling range data AC Analytical Controls developed the AC 8634 application. Gas chromatography and thermodynamics are the basis of the 8634 analyzer. The system is developed for samples within ASTM D86 groups 3 and 4. The application resides on an Agilent Technologies 7890 gas chromatograph, configured with a AC proprietary temperature programmable inlet (TPI) and flame ionization detector (FID).  The AC 8634 application uses a fast SIMDIS method to report