Since the kerogens all have different densities. You could selectively isolate  individual kerogens  by density gradient centrifugation techniques.

I don't think the density seperation via centrifugation works in this case, because densities of bitumen is to close to diffrent types of amorphous kerogen particles and some plant debris. If you want to quantify the different groups, just do a palynological slide and count the different groups at your microscope. If you want to analyse the bitumen seperately from the kerogen you have to take your residues after maceration (HCl and HF processing) and pick out the bitumen or whatever you want to analyse under the microscope with a needle. It will take some time, but it will be the only way to clearly seperate the different groups of organic matter in your residue. Good luck.

Hi Jingqiang,

First of all, I hope that this email finds you well! I wonder if you manage to develop (know of) a potential way to quantify these two fractions: pyrobitumen and kerogen?

If they have a different combustion point, then use TGA. You will only get a mass loss number though. If they have different density, you could use a specific saline concentrate with density between them, then centrifuge to separate them.

Quick wiki search thought me that Pyrobitumen is mostly insoluble in carbon disulfide. Some of them dissolve in dichloromethane, and others in benzene-methanol. I couldn't find absolute solubility for one component from either Kerogen or Pyrobitumen with a quick search, but i believe it should exist.

Maybe even using time - mass dissolution curves combined with a photometer with a stirring cuvette. Add strong solvent and you should be able to separate at least two speeds of dissolving.