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Detection of carcinogenic amines in azo dyes / F. Planelles in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 82, N° 2 (03-04/1998)
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Titre : Detection of carcinogenic amines in azo dyes Type de document : texte imprimé Auteurs : F. Planelles, Auteur ; E. Verdù, Auteur ; D. Campello, Auteur ; N. Grane, Auteur ; J. M. Santiago, Auteur Année de publication : 1998 Article en page(s) : p. 45-52 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The proclamation of 15 july 1994 of the German law concerning consumer goods, which prohibits dyes that, after the processes of reductive cleavage give certain amines, has necesitated the developed of a methodology of analysis or arylamines, the influence of the conditions of the reducing agent/dye ratio, the pH of the medium, the reaction time and the temperature in the reduction process (sodium dithionite) of hte azo dyes Direct Red 28, Acid Red 114 and Direct Blue 35 have been studied. It has been proved that the most suitable conditions for work can vary quite significantly from one dye to antoher, but if we use those conditions which are most extreme, we are assured in any case of the greatest possible yields of arylamines.
Finally, it is reported that the maximum experimental concentration of arylamine obtained in each dye approximates quite well to the theoretical estimated values, which indicates thate the yield of reductive cleavage of the azo group using sodium dithionite as a reducing agent is practically 100 %.Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=7863
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 82, N° 2 (03-04/1998) . - p. 45-52[article]Réservation
Réserver ce documentInfluence of the fat composition of greasy leathers on their bonding capacity / M. Almela in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 83, N° 1 (01-02/1999)
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Titre : Influence of the fat composition of greasy leathers on their bonding capacity Type de document : texte imprimé Auteurs : M. Almela, Auteur ; Fernando Maldonado, Auteur ; E. Verdù, Auteur ; M. J. Gascon, Auteur ; A. Carter, Auteur Année de publication : 1999 Article en page(s) : p. 32-38 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The manufacture of footwear with greasy leathers can be estimated at about 25% of the total production with bovine leathers present. This type of leather causes problems in upper-sole bonding during footwear manufacturing. Therefore, the objective of this work is to study the composition of the greasy leathers that have previously been selected as particularly problematic for bonding. An attempt is made to determine what factors (distribution and/or type of grease) most negatively influence the adhesion capability of these materials, as well as to look for alterntive ways to modify these factors during manufacturing of the leather. In accordance with the results obtained in the characterization, modifications will be proposed throughout the thickness of the leather, and in terms of the products which must be used.
The experimental controls and procedures used were the followin :
1) Quantitative determination of the greasy extract according to standard ISO 4048
2) Analysis of the greasy extract
. Determination of unsaponifiable fraction (paraffin waxes and mineral oils)
. This layer chromatography (TLC)
. High pressure liquid chromatography (HPLC)
. Gas chromatography-mass spectrometry (GC-MS)
3) Determination of the bonding capacity of the greasy leather according to standards ISO 11644 and BS-5131 Sec. 1.1.2.
Leather that contain extractable greasy matter below 15 % of the dry weight of the material, do not present bonding problems, idependently of the composition of the greasy extract. If the leathers contain more than 15 % of extractable greasy matter they can be problematic for bonding depending on the composition of the greasy extract. Analysis and subsequent tests have shown that wax or mineral oils of high molecular weight are more detrimental for bonding. It is possible to imporove the bonding results of the difficult greasy leathers by modifying the composition of the grease, e.g. replacing paraffin waxes of high molecular weight with others of low molecular weight.
Our main conclusions were :
1) Leathers with greasy extract levels above 15 % can be difficult in bonding.
2) Paraffin waxes and mineral oils with a high molecular weight are the most detrimental components for bonding. BOth products are easy to detect by thin layer chromatography aplied to the extract.
3) Alternative grease products have been proposed.Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=7855
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 83, N° 1 (01-02/1999) . - p. 32-38[article]Réservation
Réserver ce documentInter-laboratory study on formaldehyde determination by HPLC / Joaquim Font in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIII, N° 3 (02/2008)
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Titre : Inter-laboratory study on formaldehyde determination by HPLC Type de document : texte imprimé Auteurs : Joaquim Font, Auteur ; Agusti Marsal, Auteur ; Sara Cuadros, Auteur ; M. A. Juà rez, Auteur ; E. Verdù, Auteur ; M. Jorba, Auteur ; M. Reyes, Auteur ; T. Rius, Auteur ; S. Viera, Auteur Année de publication : 2008 Article en page(s) : p. 53 - 61 Note générale : Bibliogr. Langues : Américain (ame) Résumé : The colorimetric determination of formaldehyde in a water extract of a leather sample is a procedure that has been criticized because of possible interferences of other aldehydes and coloured substances that could interfere in the spectrophotometric detection. The measurement by liquid chromatography HPLC is an alternative method that was developed some years ago. This method is more sophisticated but more selective and free of the aforementioned interferences. It is not sensitive to coloured extracts. With the implementation of HPLC equipment in many laboratories, this choice has become feasible in our sector. The process is selective. Formaldehyde is separated and quantified as a derivative from other aldehydes and ketones by liquid chromatography. The free-formaldehyde and formaldehyde which is hydrolysed during extraction to yield free-formaldehyde are detected by this method. The sample is eluted with water at 40°C. The eluate is mixed with 2,4 dinitrophenylhydrazine, whereby aldehydes and ketones react to yield the respective hydrazones. These are separated by means of a reversed-phase HPLC method, detected at 350 nm and quantified. The aim of this work is to present a collaborative inter-laboratory study coordinated by the Igualada Leather Technology School and carried out with four other laboratories that had previously implemented the HPLC method or that were planning to do this. Determination of formaldehyde content in leather was carried out in each laboratory in accordance with prEN ISO 17226:2005 - HPLC Standard, developed by the Committee CEN/TC 289. Part 2 of the ISO 5725 Standard (Basic method for the determination of repeatability and reproducibility of a standard measurement method) was applied to examine the results. The study proved successful. The HPLC method achieved very reproducible results between laboratories. This work has also demonstrated that other aldehydes, glutaraldehyde included, do not interfere in the chromatographic method. The use of a PDA detector increases the confidence of the detection of formaldehyde in leather samples. En ligne : https://drive.google.com/file/d/1E16gTqYgL-Wrer6A0lzBSboae2jF1S61/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2572
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIII, N° 3 (02/2008) . - p. 53 - 61[article]Réservation
Réserver ce documentInter-laboratory study on hexavalent chromium determination in dyed skins / T. Rius in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XCVII, N° 7 (07/2002)
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Titre : Inter-laboratory study on hexavalent chromium determination in dyed skins Type de document : texte imprimé Auteurs : T. Rius, Auteur ; Joaquim Font, Auteur ; Rosa M. Cuadros, Auteur ; Sara Cuadros, Auteur ; M. Santiago, Auteur ; E. Verdù, Auteur ; Agusti Marsal, Auteur Année de publication : 2002 Article en page(s) : p. 277-283 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuir -- Teneur en chrome hexavalent
Cuir teint
Cuirs et peaux -- AnalyseIndex. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : The aim of this work is to implement a new method for the determination of the chromium (VI) content in dyed leather. A collaborative study was carried out by four Spanish laboratories to test the method, which analyses the chromium (VI) content in the extracted solutions from leather under predetermined conditions.
The well-known IUC 18 method shows deficiencies when applied to coloured leather. Thus, the new method is a modification of that. The new procedure is described in the WI 00289055 European Draft Standard, and it was developed by the CEN/TC 289 Committee. In the new method, the leather extract is decoloured by solid phase extraction in order to eliminate all the coloured substances that may interfere in the spectrophotometric detection of chromium (VI). Two commercial C18 solid phase extraction cartridges were also compared in the present study. The method was validated by applying the part 2 of the ISO 5725 Standard ("Basic method for the determination of repeatability and reproducibility of a standard measurement method") to the results obtained.
The implementation of the new method was successful given that it obviated the need for expensive instruments and produced results that were more robust and reproducible than those achieved with the existing standard method.Note de contenu : - INTRODUCTION : Aim of the work - New analytical method for the chromium (VI) content determination in dyed skins
- EXPERIMENTAL : Inter-laboratory study - Validation of the method. Application of the ISO 5725 standard - Comparison of two commercial cartridges
- RESULTS AND DISCUSSION : Chromium (VI) content determined in the inter-laboratory study - Data analysis. Application of the ISO 5725 standard for the validation of the method - Compariçson of two commercial cartridges
- Table 1 : Results from 5 analyses for Cr(VI) in each skin
- Table 2 : Averages and statistical characteristics of the results
- Table 3 : Form C : Absolute differences within cells
- Table 4 : Results of the anlaysis using DIONEX cartridges
- Table 5 : Results of the analysis using WATERS cartridges
- Table 6 : Comparison of absorbance values obtained on solutions decouloured with commercial cartridgesEn ligne : https://drive.google.com/file/d/1aFoSEl0e2kMK37JT9XcfwLEKVC3-HuWy/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39789
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XCVII, N° 7 (07/2002) . - p. 277-283[article]Réservation
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