Evaluation of aliphatic/aromatic compounds and fluorophores in dissolved organic matter of contrasting natural waters by SEC-HPLC with multi-wavelength absorbance and fluorescence detections.

The analytical high performance size exclusion liquid chromatography (SEC-HPLC) with multi-wavelength absorbance and fluorescence detections and fluorescence 3D-excitation/emission matrix (EEM) were used for the analysis of average molecular size (MS), molecular size distribution of aliphatic/aromatic compounds and fluorophores in dissolved organic matter (DOM) from Suwannee River (SRDOM) and two Karelian lakes (Vodoprovodnoe Lake - L1DOM and Onego Lake - L2DOM). The average MS of DOM samples varied in the order SRDOM > L1DOM > L2DOM. The absorbance ratios A250/A365 and A210/A254 have been used for the DOM samples characterization.

Molecular Size Distribution of Fluorophores in Aquatic Natural Organic Matter: Application of HPSEC with Multi-Wavelength Absorption and Fluorescence Detection Following LPSEC-PAGE Fractionation.

Analytical high performance size exclusion liquid chromatography (HPSEC) with multiwavelength absorbance and fluorescence detections was used for the analysis of molecular size distribution and optical properties of dissolved natural organic matter. Experiments were conducted on Suwannee River organic matter (SRNOM) and its fractions A, B, C+D preliminary obtained by combination of preparative low pressure size exclusion chromatography and polyacrylamide gel electrophoresis (LPSEC-PAGE) and purified by dialysis on membrane with nominal cutoff 10 kDa, the fractions molecular size varied in order A > B > C + D > 10 kDa. The multistep fractionation of SRNOM enabled the size-separation of at least five types of humic-like fluorophores within NOM showing emission maxima at 465, 450, 435, 420, and 405 nm.

Evaluation of Suwannee River NOM electrophoretic fractions by RP-HPLC with online absorbance and fluorescence detection.

Reversed-phase high-performance liquid chromatography (RP-HPLC) with online absorbance and fluorescence detections was used for the evaluation of Suwannee River natural organic matter (SRNOM) and its fractions A, B, and C+D, obtained by conventional size exclusion chromatography-polyacrylamide gel electrophoresis (SEC-PAGE) setup, for which the electrophoretic mobility (EM) and the absorptivity varied in the order C+D > B > A, and the molecular size (MS) in the opposite order. Analysis of SRNOM and its fractions in part of their relative irreversible adsorption on C18-column and relative distribution of eluted from the column matter on hydrophobic and hydrophilic peaks showed that hydrophobicity of fractions decreased in order: A > B > C+D. The online fluorescence detection showed that SRNOM and its fractions contained at least three groups of humic substances (HS)-like fluorophores with emission maxima at 435, 455-465, and 455/420 nm and two protein-like fluorophores with emission maxima at around 300 and 340 nm.

Analysis of electrophoretic soil humic acids fractions by reversed-phase high performance liquid chromatography with on-line absorbance and fluorescence detection.

A combination of reversed-phase high performance liquid chromatography (RP HPLC) with on-line absorbance and fluorescence detection was used for analysis of chernozem soil humic acids (HAs) and their fractions A, B and C+D with different electrophoretic mobility (EM) and molecular size (MS). Samples were injected onto the column at the identical volume and absorbance. All chromatograms exhibit the resolution of seven peaks.