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Determination of hexavalent chromium in leather by ion-exchange chromatography. Direct method versus post-column derivatisation method / Irene Compte in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 105, N° 4 (07-08/2021)
[article]
Titre : Determination of hexavalent chromium in leather by ion-exchange chromatography. Direct method versus post-column derivatisation method Type de document : texte imprimé Auteurs : Irene Compte, Auteur ; Rosa M. Cuadros, Auteur ; Anna Bacardit, Auteur ; Felipe Combalia, Auteur ; Joaquim Font, Auteur Année de publication : 2021 Article en page(s) : p. 175-182 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chromatographie par échange d'ions
Chrome hexavalent
Cuir -- Teneur en chrome hexavalent
Cuirs et peaux -- Analyse
Extraction (chimie)Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The ISO 17075-2 Standard was published in 2017. In this standard appeared for the first time the determination of hexavalent chromium in leather by liquid chromatography. Two alternative instrumental options are proposed in this method: the direct determination of the absorbance of the chromate peak (Annex B of the Standard) or after the post-column derivatisation with diphenylcarbazide (Annex C). Instrumental performance parameters and economic costs between both methods are compared in this paper. One hundred different leathers were analysed by both chromatographic systems. The two methods proved very good correlation. The post-column method has a higher instrumental sensitivity compared to the direct detection method, which is important to reduce the uncerteinty of the measure in semples around the 3mg/kg current regulatory limit. Other important advantages are its absolute selectivity, which allows the secure identification of the hexavalent chromium in all type of complicated matrixes, and the higher durability of its well protected columns due to the use of cost-effective guard columns. Due to the technical advantages and the slight difference in the equipment cost, which can be compensated thanks to the larger lifespan of the chromatographic columns, it is concluded that the post-column method is the most suitable option for the most determination of hexavalent chromium in leather. Note de contenu : - MATERIALS AND METHODS : Chemicals - Samples - Extraction
- RESULTS AND DISCUSSION : Optimisation of the post-column conditions - Method validation - Repeatability and accuracy of the post-column determination method - Analysis of leather samples - Economic assessment
- Table 1 : Optimisation of the mobile phase ionic strength
- Table 2 : Optimisation of the mobile phase flow
- Table 3 : Optimisation of the post-column reagent flow
- Table 4 : Comparison of three different cartridges
- Table 5 : Concentration of Cr(VI) obtained in 14 leather samples, all of them above 3.0 mg/kg
- Table 6 : Evaluation of the Cr(VI) results in 100 leather samplesEn ligne : https://drive.google.com/file/d/13VmY0k59wMY6TKIykzgnXLA9wEalFumN/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36106
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 105, N° 4 (07-08/2021) . - p. 175-182[article]Réservation
Réserver ce documentA simple test to determine the propensity of a fatliquor to trigger the formation of chromium (VI) in leather / Irene Compte in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVII, N° 11 (11/2022)
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Titre : A simple test to determine the propensity of a fatliquor to trigger the formation of chromium (VI) in leather Type de document : texte imprimé Auteurs : Irene Compte, Auteur ; Rosa M. Cuadros, Auteur ; Francina Izquierdo, Auteur ; Felipe Combalia, Auteur ; Anna Bacardit, Auteur Année de publication : 2022 Article en page(s) : p. 480-488 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chimie analytique
Chrome hexavalent
Chrome trivalent -- Oxydation
Liqueurs de tannageIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Since the entry into force of the EU Commission Regulation regarding hexavalent chromium in leather articles in 2014, it is of paramount importance to follow good manufacturing practices to ensure the production of leather not only free of Cr(VI) but with no tendency to its formation. The equilibrium between Cr(III) and Cr(VI) in leather can be disturbed under stressful environmental conditions such as light or heat exposure. These factors could trigger the lipid peroxidation of unprotected unsaturated fatliquoring agents, thus leading to the oxidation of Cr(III) to Cr(VI). Due to the relevance that the oxidation of the fatliquoring agents has in the subsequent Cr(VI) formation, the Propensity Test has been developed and verified as an innovative verifying in-house tool for tanners to verify that each of the fatliquoring agents used in the tannery processes are properly protected against oxidation and thus, that Cr(VI) formation is not triggered.The method has four simple steps and can be easily carried out in the tanneries’ pilot plant. It does not require special equipment or specific apparatus because all the necessary instruments are usually available in any tannery and the skills needed to perform the test are the same that leather technicians use in their day-to-day work, so the implementation cost is practically non-existent.This work leads to the conclusion that there is a higher possibility of Cr(VI) formation among sheep skins rather than among calf hides. The rechroming process also presents risks regarding Cr(VI) content in leather, however, in this study it has been shown that rechroming does not increase Cr(VI) formation risks when the fatliquoring agents are properly protected against autoxidation. Therefore, using a well-protected fatliquoring agent is mandatory for the purpose of producing Cr(VI)-free leather despite the type of leather. Note de contenu : - INTRODUCTION : Influence of faliquoring in Cr(VI) formation - Testing for Cr(VI)-free raw materials
- EXPERIMENTAL : Skins and hides - Materials and facilities - Propensity test recipe - Testing for hexavalent chromium - Apparent density of leather
- RESULTS AND DISCUSSION : Performance of the propensity test - Validation of thepropensity test - Cr(VI) content depending on the type of leather - Influence of the rechroming process
- Table 1 : Recipe to test a fatliquoring agent for propensity to the formation of hexvalent chromium
- Table 2 : Fatliquors tested during the development of the propensity test
- Table 3 : Cr(VI) content in mg/kg of the experiments for the developing of the propensity test
- Table 4 : Apparent density of the fatliquored leathers.
- Table 5 : Comparison of the Cr(VI) content in mg/kg of the rechrçmed and not-rechromed leathersDOI : https://doi.org/10.34314/jalca.v117i11.6294 En ligne : https://drive.google.com/file/d/1JTGfnNwD0pUvNwz6m4yhvoUoLEx2yOPA/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38341
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVII, N° 11 (11/2022) . - p. 480-488[article]Réservation
Réserver ce documentUse of long-chain synthetic phenolic antioxidants to produce chromium-tanned leather without risk of hexavalent chromium formation / Irene Compte in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 10 (10/2023)
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Titre : Use of long-chain synthetic phenolic antioxidants to produce chromium-tanned leather without risk of hexavalent chromium formation Type de document : texte imprimé Auteurs : Irene Compte, Auteur ; Quim Torras, Auteur ; Francina Izquierdo, Auteur ; Rosa M. Cuadros, Auteur ; Anna Bacardit, Auteur Année de publication : 2023 Article en page(s) : p. 439-449 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antioxydants
Auto-oxydation
Cuirs et peaux de moutons
Essais accélérés (technologie)
Lipides
Phénols
Tannage au chromeIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Chromium tanned leather is the widest form of leather tanning across the world, but it might involve a risk of hexavalent chromium formation, which is restricted in leather products above 3 mg/ kg. Among other conditions, certain processes might lead to the oxidation of natural fats or fatliquoring agents with unsaturated carbon-carbon bonds, thus generating free radical molecules that can contribute to the Cr(III) oxidation to Cr(VI). The autooxidation of unsaturated lipids is promoted by exposure to high temperatures and light, specifically UV radiation. Among other relevant manufacturing practices, the addition of synthetic phenolic antioxidants (SPAs) during the synthesis of fatliquoring agents or during leather manufacturing can be a relevant tool for preventing lipid auto-oxidation.
The efficiency of the long-chain synthetic antioxidant 1135 (AO1135, CAS RN® 125643-61-0) has been assessed for Cr(VI) prevention. The performance of AO1135 has been tested in two different skin types (sheepskin, woolly sheepskin), with two different fatliquoring agents (unprotected and protected against oxidation). The protected fatliquoring agent was formulated with AO1135. Also, two commercial products that contain the AO1135 in its formulation have been applied to leathers. Upon completion of the post-tanning process, the leathers have undergone two different thermal ageing processes.
AO1135 has been verified an effective SPA for Cr(VI) prevention and its application during the post-tanning process does not alter the visual aspect of the leathers. Otherwise, if the post-tanning recipe does not contain well-sourced raw materials or Cr(VI) prevention tools, unsaturated fatliquoring agents or natural fats present in the skins can be a cause for Cr(VI) formation.Note de contenu : - INTRODUCTION : Origins of Cr(VI) in leather-hexavalent chromium containing substances - Influence of the pH value - Oxidation of fatliquoring agents - Natural extracts as a way for reducing formed Cr(VI) - Synthetic phenolic antioxidants as a tool for preventing lipid auto-oxidation - Forcing lipid auto-oxidation in leather - Determining the efficiency of antioxidant 1135 to prevent Cr(VI) formation - Commercial products with synthetic phenolic antioxidant
- EXPERIMENTAL : Design of the experiment - Samples - Chemicals and appartus - Methods - Determination of natural fat content in leather
- RESULTS : Cr(VI) content in the tanned leathers - Dispersion of the Cr(VI) content depending on the different parts of the leather
- DISCUSSION : Use of synthetic phenolic auxiliaries (AO1135) and its consequences on the Cr(VI) content - Zone of the leather and Cr(VI) distribution - Effect of different ageing treatments in Cr(VI)
- Table 1 : Structure of the study
- Table 2 : Conditions of sample exposure prior to Cr(VI) testing
- Table 3 : Cr(VI) content according to ISO 17075-2:2017 of sheep-skins produced
- Table 4 : Cr(VI) content according to ISO 17075-2:2017 of wooly sheep leathers produced
- Table 5 : Average and % RSD of leathers with Cr(VI) detectionDOI : https://doi.org/10.34314/jalca.v118i10.8232 En ligne : https://drive.google.com/file/d/1a3qDDoXd-GKDH-5gVHfu1cAh_Tje3ck8/view?usp=share [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39942
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 10 (10/2023) . - p. 439-449[article]Réservation
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