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| rdf:type
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| Description
| - The methylation of humic acids (HA) with dimethylsulfate in acetone and methanol followed by the iodometric determination of the methoxy groups (Zeisel reaction) were applied to determine the contents of OH groups in solid samples of HA of different origins. For the coal- and peat-derived HA samples, the contents of OH groups determined after methylation in acetone ranged from 6.6 to 8.7 mmol/g, whereas the contents of OH groups determined after methylation in methanol ranged from 4.0 to 5.0 mmol/g. These differences may be related to the content of carboxylic groups in the HA molecule that were not methylated in methanol, as confirmed by a comparison with results of conventional titrimetric determinations. Observed differences were interpreted as results of different polarity of both solvents and alkalinity of the reaction mixture during the methylation. The contents of alcoholic groups as well as some other minor OH groups can be estimated using the OH group contents obtained after methylation
- The methylation of humic acids (HA) with dimethylsulfate in acetone and methanol followed by the iodometric determination of the methoxy groups (Zeisel reaction) were applied to determine the contents of OH groups in solid samples of HA of different origins. For the coal- and peat-derived HA samples, the contents of OH groups determined after methylation in acetone ranged from 6.6 to 8.7 mmol/g, whereas the contents of OH groups determined after methylation in methanol ranged from 4.0 to 5.0 mmol/g. These differences may be related to the content of carboxylic groups in the HA molecule that were not methylated in methanol, as confirmed by a comparison with results of conventional titrimetric determinations. Observed differences were interpreted as results of different polarity of both solvents and alkalinity of the reaction mixture during the methylation. The contents of alcoholic groups as well as some other minor OH groups can be estimated using the OH group contents obtained after methylation (en)
- Methylace huminových kyselin (HA) dimethylsíranem v acetonu a methanolu s následným iodometrickým stanovením methoxy skupin (Zeiselovou reakcí) byla využita pro stanovení obsahu -OH skupin v pevných huminových kyselinách různého původu. Pro vzorky HA z uhlí a rašeliny se obsah -OH skupin po methylaci v acetonu pohyboval v rozmezí 6,6-8,7 mmol/g, zatímco obsah -OH skupin stanovený po methylaci v methanolu byl v rozmezí 4,0-5,0 mmol/g. Tyto rozdíly souvisí s obsahem OH skupin v molekule HA, které nepodlehají methylaci v methanolu, jak lze doložit i srovnáním s výsledky konvenčních titračních stanovení. Pozorované rozdíly byly interpretovány jako důsledek rozdílné polarity obou rozpouštědel a alkality reakční směsi během methylace. Obsah akoholických OH skupin a dalších minoritních OH skupin může být stanoven s využitím obsahů OH skupin stanovených po methylaci v obou rozpouštědlech v kombinaci s výsledky konvenčních stanovení kyselých funkčních skupin. Průměrné hodnoty opakovatelnosti byly 0,38 mmol/g (cs)
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| Title
| - Determination of OH groups in humic acids using methylation with dimethylsulfate
- Determination of OH groups in humic acids using methylation with dimethylsulfate (en)
- Stanovení skupin OH v huminových kyselinách s využitím methylace dimethylsíranem (cs)
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| skos:prefLabel
| - Determination of OH groups in humic acids using methylation with dimethylsulfate
- Determination of OH groups in humic acids using methylation with dimethylsulfate (en)
- Stanovení skupin OH v huminových kyselinách s využitím methylace dimethylsíranem (cs)
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| skos:notation
| - RIV/44555601:13520/08:00004394!RIV09-MSM-13520___
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| http://linked.open...avai/riv/aktivita
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| http://linked.open...avai/riv/aktivity
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| http://linked.open...iv/cisloPeriodika
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| http://linked.open...vai/riv/dodaniDat
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| http://linked.open...aciTvurceVysledku
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| http://linked.open.../riv/druhVysledku
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| http://linked.open...iv/duvernostUdaju
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| http://linked.open...titaPredkladatele
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| http://linked.open...dnocenehoVysledku
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| http://linked.open...ai/riv/idVysledku
| - RIV/44555601:13520/08:00004394
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| http://linked.open...riv/jazykVysledku
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| http://linked.open.../riv/klicovaSlova
| - Humic acids; OH groups content; carboxylic groups content; methylation (en)
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| http://linked.open.../riv/klicoveSlovo
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| http://linked.open...odStatuVydavatele
| - GB - Spojené království Velké Británie a Severního Irska
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| http://linked.open...ontrolniKodProRIV
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| http://linked.open...i/riv/nazevZdroje
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| http://linked.open...in/vavai/riv/obor
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| http://linked.open...ichTvurcuVysledku
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| http://linked.open...cetTvurcuVysledku
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| http://linked.open...vavai/riv/projekt
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| http://linked.open...UplatneniVysledku
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| http://linked.open...v/svazekPeriodika
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| http://linked.open...iv/tvurceVysledku
| - Kozler, J.
- Kuráň, Pavel
- Madronová, L.
- Novák, J.
- Janoš, Pavel
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| http://linked.open...ain/vavai/riv/wos
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| issn
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| number of pages
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| http://localhost/t...ganizacniJednotka
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