ANALYSIS OF FULVIC-ACIDS USING HPLC UV COUPLED TO FT-IR SPECTROSCOPY/

Reversed-phase high performance liquid chromatography (RP-HPLC) couple d with an ultraviolet (UV) detector was used to separate three fulvic acid samples into two major fractions which contain several components based on the polarity of the samples. The chromatographic effluent wa s then directed into the LC-Transform, an interface between HPLC and F ourier transform infrared spectroscopy (FT-IX). The LC-Transform used a heated ultrasonic nozzle to evaporate all the HPLC mobile phase and deposit the eluates onto a rotating sample collection disk. The collec tion disk with the sample was subsequently analyzed by FT-IR. The UV c hromatogram and the corresponding FT-IR chromatogram (Gram-Schmidt rec onstruction) agreed with each other quite well. Spectral comparisons b etween the unseparated fulvic acid and separated fractions were done. Most of the typical functional groups found in fulvic acid, such as ca rboxylic acids, alcohols and phenols, were present in all fractions se parated. Significant amounts of the aliphatic groups were detected in the least polar fractions which responded only to the FT-IR measuremen t. The carboxyl groups in the early eluting fractions were determined to be present in the form of carboxylate anions. Carboxylic add anhydr ides were found in the soil fulvic acid extracted from Amherst, MA. Se cond-derivative spectroscopy was used to confirm the anhydride absorba nce band.