Extraction and analysis of nitrogen, phosphorus and carbon fractions in plant material

Abstract A method is described for the extraction and analysis of various nitrogen‐, phosphorus‐ and carbon‐containing fractions from plant material. Lipids were extracted with chloroform/methanol and chloroform/methanol/water. Soluble nitrogen (nitrate, ammonia, and amino acid), phosphorus (inorganic and sugar phosphate) and carbon (sugar and tannin) fractions were extracted with cold trichloracetic acid. Hot soluble nitrogen and phosphorus (nucleic acid) and carbon (starch and tannin) fractions were extracted with hot trichloracetic acid. Protein remained in the residue. A detailed automated scheme is described for the analysis of each of the above fractions. Also included are methods for analyzing triglyceride, hydrolyzable ester phosphate and phytic acid.