| Titre : |
A simple test to determine the propensity of a sample of leather to the formation of chromium |
| Type de document : |
texte imprimé |
| Auteurs : |
Joaquim Font, Auteur ; Marta Bacardit, Auteur ; Niria Pascual ; Rosa M. Cuadros ; Francina Izquierdo |
| Année de publication : |
2018 |
| Article en page(s) : |
p. 65-71 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Analyse quantitative (chimie)
Colorimétrie
Cuir -- Teneur en chrome hexavalent
Cuirs et peaux -- Analyse
Décoloration
Extraction par solvant
PyrolyseLa pyrolyse est la décomposition ou thermolyse d'un composé organique par la chaleur pour obtenir d'autres produits (gaz et matière) qu'il ne contenait pas. L'opération est réalisée en l'absence d'oxygène ou en atmosphère pauvre en oxygène pour éviter l'oxydation et la combustion (L’opération ne produit donc pas de flamme). Il s'agit du premier stade de transformation thermique après la déshydratation.
Elle permet généralement d'obtenir un solide carboné, une huile et un gaz. Elle débute à un niveau de température relativement bas (à partir de 200 °C) et se poursuit jusqu'à 1 000 °C environ. Selon la température, la proportion des trois composés résultants est différente.
|
| Index. décimale : |
675 Technologie du cuir et de la fourrure |
| Résumé : |
Since the EU Commission Regulation of chromium(VI) in leather articles, there is a huge demand of analyses and controls in the leather sector for this parameter.
However, for many tanners and leather dealers, the necessary cost to have a laboratory capable to carry out the analyses according to an ISO method is not affordable.
An easy test has been developed to carry out a screening of a leather sample in order to check out its compliance with the Cr(VI) restriction. This test is able to distinguish leathers that contain chromium(VI) or show signs of tendency to develop it, from leathers that even after thermal ageing exposure remain free of it.
The test is based on the scientist principle of the ISO 17075-1 method. Some operations of this Standard have been adapted with the aim of saving costs and simplifying and shortening the workload of the test. The essential criterion of this adaptation has been that the developed test does not lead to false negatives.
The only required devices are a laboratory oven, a balance of 0.01g of resolution, and a shaker. Neither a spectrophotometer nor a colorimeter is necessary.
The method has four main steps. The first one is an ageing process at 80°C during 24 hours. After cooling down for 30 minutes, the sample is extracted for one hour, using an overhead rotatory shaker or a magnetic stirrer. The third step is the discoloration of the extract, to remove the dyes of the colored solution so as to eliminate interferences. Finally, the extract is assessed by visual colorimetry. The workload per sample is about 40 minutes.
So far, more than 300 samples of leather have been tested. The kit performed very well and only gave 5% of false positives. The kit did not commit any false negative. |
| Note de contenu : |
- MATERIALS AND METHODS : Samples - Reagents and instruments for the LeatherKit_Cr6 method - Instruments for the ISO 17075-2 reference method - Operating procedure for LeatherKit_Cr6 method - Measurement
- RESULTS AND DISCUSSION : Ageing - Cooling down time - Degasification of samples and extration solution - Extraction procedure - Color removal - Determination |
| En ligne : |
https://drive.google.com/file/d/1-Pc0JEd9a6YcAPhK0_-PJAntrsYBnDj0/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=29955 |
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXIII, N° 2 (02/2018) . - p. 65-71
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A simple test to determine the propensity of a sample of leather to the formation of chromium in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXIII, N° 2 (02/2018)
