Dear all members In my reaserch I want to measure the amounts of humic and fulvic acids in soil but I faced to a problem.I have extracted and fractionated them by means of NaOH and changes in pH but I can not measure the amount of fulvic and humic acid in final solution with low pH (fulvic acid) and precipitated materials (humic acid) because I do not access to necessary tools and I am seeking for a simple presedure.Is it a true method to measure by drying and weighting final solution and precipitated materials. I shall be greatful if you will help me with your advices and comments. Regards Hossein Karimi Department of Soil Science Agricultural College,Ferdowsi University,Mashhad,IRAN P.O.Box 91775-1163 E-Mail http://skarimi343@yahoo.com --------------------------------- Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now