Zur Einwirkung von Ozon auf Wolle und Aminosäuren
type: CreativeWork
description: Solid histidine shows no reaction during ozonation. In contrast, the ozonation of aqueous solutions of histidine reveals quick and effective oxidation. Ozone consumption during histidine treatment is passing two phases. Depending on the duration of the ozone treatment the consumption rate is decreasing in a ratio of 3.5:1. Histidine ozonation in unbuffered liquors shows a characteristic decline of pH value in three phases. The pH shift towards acidic values points out that the imidazole ring of histidine is preferentially attacked. Depending on the duration of the ozone treatment the formation of about eight decomposition products of different polarity at pH 7.2 are detected by HPLC-analysis. Thin layer chromatography of the ozonation product resulted in the detection of six different products. The composition of the product mixture depends on the pH value of the liquor. Variation of pH within a range of 3 and 11 leads to a higher number of products with increasing pH. At the same time, the amounts of the different products are more equally distributed on increasing pH. At high pH there is no product dominating the mixture whereas at lower pH particular products are preferentially formed. Amino acid analysis of the product mixtures obtained by histidine ozonation without prior hydrolysis showed the formation of aspartic acid (Asp), asparagine (Asn) and serine (Ser). Serine formation is considered to result from secondary decomposition of aspartic acid. As a result of ozonolytic histidine decomposition the formation of acetaldehyde as well as imidazole was found by mass spectroscopic analysis. In addition, a product with high molecular mass (M=305 g/mol) is detected that could not be identified. Ozonation of histidine leads to the formation of different radical species which are detectable by means of electron paramagnetic resonance (EPR) spectroscopy. Formation of these species resp. their stability could be enhanced using spin trapping agents. Impact of ozone on th…
abstract: Solid histidine shows no reaction during ozonation. In contrast, the ozonation of aqueous solutions of histidine reveals quick and effective oxidation. Ozone consumption during histidine treatment is passing two phases. Depending on the duration of the ozone treatment the consumption rate is decreasing in a ratio of 3.5:1. Histidine ozonation in unbuffered liquors shows a characteristic decline of pH value in three phases. The pH shift towards acidic values points out that the imidazole ring of histidine is preferentially attacked. Depending on the duration of the ozone treatment the formation of about eight decomposition products of different polarity at pH 7.2 are detected by HPLC-analysis. Thin layer chromatography of the ozonation product resulted in the detection of six different products. The composition of the product mixture depends on the pH value of the liquor. Variation of pH within a range of 3 and 11 leads to a higher number of products with increasing pH. At the same time, the amounts of the different products are more equally distributed on increasing pH. At high pH there is no product dominating the mixture whereas at lower pH particular products are preferentially formed. Amino acid analysis of the product mixtures obtained by histidine ozonation without prior hydrolysis showed the formation of aspartic acid (Asp), asparagine (Asn) and serine (Ser). Serine formation is considered to result from secondary decomposition of aspartic acid. As a result of ozonolytic histidine decomposition the formation of acetaldehyde as well as imidazole was found by mass spectroscopic analysis. In addition, a product with high molecular mass (M=305 g/mol) is detected that could not be identified. Ozonation of histidine leads to the formation of different radical species which are detectable by means of electron paramagnetic resonance (EPR) spectroscopy. Formation of these species resp. their stability could be enhanced using spin trapping agents. Impact of ozone on th…
author: Quadflieg, Joachim
language: ger
keywords: info:eu-repo/classification/ddc/540, Wolle, Aminosäuren, Ozonisierungsreaktion, Histidin, Nylon, Chemie
date published: 2003
date modified: 2026-07-30T19:42:39Z
provider: RWTH Aachen University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Publikationsserver der RWTH Aachen University