"RIV/00216305:26310/07:PU70240!RIV08-MSM-26310___" . "13"^^ . . "The potential of high resolution ultrasonic analysis (HRUS) in humic acid colloidal properties research has been demonstrated. Sodium salts of humic acids from soil and lignite showed similar behaviour, supporting the hypothesis that, at both neutral and alkaline pH, they aggregate from very low concentration. The same conclusion can be reached for solutions at high ionic strength. We tried to apply the same procedure as used for the study of micellization and determination of critical micelle concentration of common surfactants. As expected, our experiments did not show the same break as demonstrated on the HRUS records for sodium dodecyl sulfate, at least in the range of measured concentration (i.e. from 0.001 up to 10 g/L). The colloidal state of humic acids in aqueous solution is very sensitive to the presence of other, both charged and neutral, molecules. Aggregation of humic acids can be disturbed or promoted, depending on the concentration, by electrostatic or other weak interactions with extra" . . . . "\u0160mejkalov\u00E1, Daniela" . "New insights into aggregation and conformational behaviour of humic substances: Application of high resolution ultrasonic spectroscopy" . . "Peka\u0159, Miloslav" . "38" . . "GB - Spojen\u00E9 kr\u00E1lovstv\u00ED Velk\u00E9 Brit\u00E1nie a Severn\u00EDho Irska" . . "New insights into aggregation and conformational behaviour of humic substances: Application of high resolution ultrasonic spectroscopy"@en . . "\u010Cechlovsk\u00E1, Hana" . "ORGANIC GEOCHEMISTRY" . . "Nov\u00FD pohled na agrega\u010Dn\u00ED chov\u00E1n\u00ED huminov\u00FDch kyselin: aplikace vysoce rozsli\u0161ovac\u00ED ultrazvukov\u00E9 spektroskopie"@cs . "Ku\u010Der\u00EDk, Ji\u0159\u00ED" . "Nov\u00FD pohled na agrega\u010Dn\u00ED chov\u00E1n\u00ED huminov\u00FDch kyselin: aplikace vysoce rozsli\u0161ovac\u00ED ultrazvukov\u00E9 spektroskopie"@cs . "RIV/00216305:26310/07:PU70240" . "[AC118E316A19]" . "437146" . "humic substances, aggregation, high resolution ultrasonic spectroscopy"@en . "2098-2110" . "4"^^ . "4"^^ . "New insights into aggregation and conformational behaviour of humic substances: Application of high resolution ultrasonic spectroscopy" . . . "New insights into aggregation and conformational behaviour of humic substances: Application of high resolution ultrasonic spectroscopy"@en . . "0146-6380" . . "Nov\u00FD pohled na agrega\u010Dn\u00ED chov\u00E1n\u00ED huminov\u00FDch kyselin: aplikace vysoce rozsli\u0161ovac\u00ED ultrazvukov\u00E9 spektroskopie"@cs . . . . "Z(MSM0021630501)" . "The potential of high resolution ultrasonic analysis (HRUS) in humic acid colloidal properties research has been demonstrated. Sodium salts of humic acids from soil and lignite showed similar behaviour, supporting the hypothesis that, at both neutral and alkaline pH, they aggregate from very low concentration. The same conclusion can be reached for solutions at high ionic strength. We tried to apply the same procedure as used for the study of micellization and determination of critical micelle concentration of common surfactants. As expected, our experiments did not show the same break as demonstrated on the HRUS records for sodium dodecyl sulfate, at least in the range of measured concentration (i.e. from 0.001 up to 10 g/L). The colloidal state of humic acids in aqueous solution is very sensitive to the presence of other, both charged and neutral, molecules. Aggregation of humic acids can be disturbed or promoted, depending on the concentration, by electrostatic or other weak interactions with extra"@en . . "1" . "26310" . .