There are plenty of protocols available for the fractionation of humic acid from fulvic acid. Acidification generally separates the humic acid as fulvic acid stays in solution. Similar topic has been discussed on Researchgate many times in the past, you can search for those too. You need to reduce the pH of the solution very low to precipitate humic acid out. However methods using organic acid for the separation is not very common. You should also know that Humic acids undergo transformations if not kept in low pH so unless you do that interactive studies using it will not be successful. Also the exact extraction protocol should be designed by you depending on the source of the acids.

This link < Article Methods for the Assessment of Humic Substances Quality in Forest Soils

Regards,

Dr. Abhishek Mukherjee

I do agree with Dr Abhishek Mukherjee regarding fractionation of humic acid from fulvic acid. There are so many standard methods in the literature that will help any one for this.

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Please go through this document, hope this will serve you better.

There is much debate on humic substances going on, also i Research Gate.. In a recent article in Nature, Lehmann and Kleber among other things made a suggestion to drop terms like "humus", "humic substances", and "humification" from the language used to describe soil organic matter. As HA and FA are not simple chemical components but complexes/associates of smaller building blocks, it is necessary to follow a standard procedure for their isolation and separation. As quite correctly pointed out by Binder Singh, the protocol of the IHSS should be followed. Only in this way we will be able to meaningful compare results on HA and FA obtained by different researchers.

Luuk K Koopal I couldn't find the protocol of the IHSS by Singh. I would be appreciated if you can share with us.

Thank you everyone for your advice.

I am particularly, looking for any organic acid that may help me to successfully separate the HA and FA. I normally follow the guidelines of the IHSS (alkaline extraction followed by acidification). I use the inorganic acid for separation. My question is, have you tried or know someone who tried organic acid for separation?

Thanks,

Dereje

Why you seek to use organic acid to separate HA and FA when there is mature method like IHSS (alkaline extraction followed by acidification) to achieve your goal?