Sorption of Polycyclic Aromatic Compounds to Humic and Fulvic Acid HPLC Column Materials

Abstract

Two different humic acids (HA) and a fulvic acid (FA) were chemically immobilized to a high performance liquid chromatography (HPLC) silica column material. The immobilization was performed by binding amino groups in HA/FA to the free aldehyde group in glutardialdehyde attached to the silica gel. The HPLC column materials were compared with a blank column material made by applying the same procedure but without immobilizing HA or FA. Also, a column was made by binding carbonyl groups in HA to amino groups attached to the silica gel. The humic substances were selected to secure appropriate variation of their structural features. The retention factors of 45 polycyclic aromatic compounds (PAC) to the four columns were determined by HPLC. The advantage of the technique is a large number of compounds can easily be studied. The binding procedure does not appear to cause a drastic selection between the HA molecules. The k' values obtained for the two Aldrich HA columns agree in general reasonably. The retention or sorption of the compounds increased with the size of the PAC and the number of lipophilic substituents, but decreased when polar substituents were present. The PAC retention was much stronger to the two HA columns than to the FA and blank column, both for hydrophobic polycyclic aromatic hydrocarbons (PAH) and the polar PAC. Other factors impacting the PAC binding may be specific interactions with HA and the ionic strength of the aqueous phase. The technique has been applied to do direct determinations of Koc.

The application of high-performance liquid chromatography humic acid columns in determination of Koc of polycyclic aromatic compounds

“…This work presents some improvements of earlier work [4], mentioned as the carbonyl procedure in [5]. The most important improvement is the higher content of humic acid in the HPLC column together with a lowering of carrier carbon.…”

Kinetics of the sulfate radical‐mediated photo‐oxidation of humic substances

“…There is a good agreement between the experimental and simulated traces (data not shown). Simulations of the experiments obtained in the presence of various amounts of AHA were done with the same parameters [16,17].…”

Efficacy of Probiotics and Nutrients in Functional Gastrointestinal Disorders: A Preliminary Clinical Trial

“…The minerals in our study were ionic plant-based fulvic acids. Fulvic acids are a complex and heterogeneous milieu of compounds with varying molecular weights and chemical structures formed from the humification process of degrading plants and animal debris [27]. In general, fulvic acids are soluble across broad pH ranges and are a major fraction of naturally occurring organic matter [28].…”