Accueil
JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) . Vol. CIII, N° 3Mention de date : 02/2008Paru le : 18/02/2008 |
Dépouillements
Ajouter le résultat dans votre panierInter-laboratory study on formaldehyde determination by HPLC / Joaquim Font in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIII, N° 3 (02/2008)
[article]
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 documentRemoval of aromatic organic acids from aqueous solution by using chrome leather waste as an adsorbent / Zhang Mina in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIII, N° 3 (02/2008)
[article]
Titre : Removal of aromatic organic acids from aqueous solution by using chrome leather waste as an adsorbent Type de document : texte imprimé Auteurs : Zhang Mina, Auteur ; Xuepin Liao, Auteur ; Jiang Sujie, Auteur ; Bi Shi, Auteur Année de publication : 2008 Article en page(s) : p. 62 - 67 Note générale : Bibliogr. Langues : Américain (ame) Résumé : Chrome leather shavings were used to prepare adsorbent for removal of aromatic organic acids from aqueous solution. Benzoic acid, o-, m-, and p-phthalic acids, salicylic acid and p-hydroxyl benzoic acid, which are common pollutants in waste water, were used as adsorbates in this study to investigate the sorption behavior of the adsorbent made from chrome leather waste. It was found that the sorption capacity of aromatic organic acids on the adsorbent depends largely on the molecular structures of these compounds. The sorption capacity of o-phthalic acid on the adsorbent was as high as 2.8mmol/g in experimental conditions, and that of salicylic acid was around 0.41mmol/g. However, no significant sorption was observed in the case of benzoic acid. Sorption isotherms of aromatic organic acids are typically non-linear ones, and can be well fitted by adsorption-partition model. The contributions of adsorption and partition to total sorption of these compounds on the adsorbent were quantitatively described. It was found that, for o-phthalic acid, the function of partition is predominant, and for p-phthalic acid, adsorption plays a key role. As for m-phthalic acid and salicylic acid, the contributions of adsorption and partition to total sorption depend on the concentration of adsorbate. Those results demonstrate that this adsorbent can be applied to remove aromatic organic acids from wastewaters in a wide range of concentration. En ligne : https://drive.google.com/file/d/1SXS3bEjUrqft0dbxvs1wIkUuJtUFZlMV/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2573
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIII, N° 3 (02/2008) . - p. 62 - 67[article]Réservation
Réserver ce documentNatural dyeing of leathers using natural materials / Jonnalagadda Raghava Rao in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIII, N° 3 (02/2008)
[article]
Titre : Natural dyeing of leathers using natural materials Type de document : texte imprimé Auteurs : Jonnalagadda Raghava Rao, Auteur ; Balachandran Unni Nair, Auteur ; Subramani Saravanabhavan, Auteur ; Kalarical Janardhanan Sreeram, Auteur ; E. Thangaraj, Auteur ; A. Prakash, Auteur Année de publication : 2008 Article en page(s) : p. 68 - 75 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Environmental constraints on discharge of dye containing wastewater has forced us to look for natural dyes, which have several advantages like low toxicity, cheap and easy availability etc. Natural dyes are obtained from plants (e.g., Alizarin, Catechu, Indigo and Logwood), from animals (e.g., cochineal, kermes and tyrian purple) and from certain naturally occurring minerals (e.g., Ocher and Prussian blue). In this study, an attempt has been made to develop leathers, colored using natural dyes such as Rhine, Rhine M, Indus, Pacific, Caspian, Henna and modified Logwood. This study would be more beneficial to the leather industry. Also, an effort has been made to produce wide range of shades through mordanting with eco-benign metals such as aluminum, copper and tin. Twenty four shades were developed using combination of seven natural colorants by mordanting with three metal ions. The reflectance spectra for all colors have been studied. The visual appearance and their fastness properties have also been evaluated and the test results are satisfactory. Developed colors have potential value in the global leather market in the context of environmentally benign leather processing. En ligne : https://drive.google.com/file/d/1IsXxfOTT9oPapQ4D3b48xdviNjBWYnj2/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=2574
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIII, N° 3 (02/2008) . - p. 68 - 75[article]Réservation
Réserver ce documentSoaking : Balancing operational and quality issues using both fresh and brine cured hides / George Stockman in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIII, N° 3 (02/2008)
[article]
Titre : Soaking : Balancing operational and quality issues using both fresh and brine cured hides Type de document : texte imprimé Auteurs : George Stockman, Auteur ; Dean Didato, Auteur ; Susan Steele, Auteur ; Chris Black, Auteur ; Ron Allison, Auteur Année de publication : 2008 Article en page(s) : p. 76-85 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Cuirs et peaux
Cuirs et peaux de bovins
Hyaluronique, acideL'acide hyaluronique est un type de polysaccharide (plus précisément une glycosaminoglycane) non fixé à une protéine centrale et largement réparti parmi les tissus conjonctifs, épithéliaux et nerveux animaux.
Il se trouve notamment dans l'humeur vitrée et le liquide synovial. Il est l'un des principaux composants de la matrice extracellulaire ainsi que de certaines mucoprotéines lorsqu'il est associé à une fraction protéique.
Depuis les années 1990, il est très utilisé dans divers dispositifs médicaux, médicamenteux et cosmétiques (présenté dans ce dernier cas comme "antistatique, humectant, hydratant, conditionneur cutané, anti-âge, etc."), bénéficiant d'un effet de mode grandement soutenu par une large publicité commerciale.
Contribuant de façon significative à la prolifération et à la migration des cellules, l'acide hyaluronique est aussi impliqué dans la progression de certains cancers. (Wikipedia)
Mesure
Peaux brutes -- Trempe
SaumurageIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : The past three decades have heralded dramatic changes in raw material for tanning in the U.S. Modern blueing facilities lie close to the source of hides and are either captive to the packinghouses or have established long-term contracts for purchase and receipt of the fresh hides on a continuing basis. Typically, tanners are required to receive the hides daily, in concert with the slaughter schedule, with little to no variance possible.
Tanners often process both brine cured hides as well as fresh, thus optimizing time management and production demands.
It is commonly accepted that variations in processing time, float, type of equipment (paddle or drum), bactericide, pH, wetting agents and protease-based enzymes are necessary in response to both end-product requirements as well as raw material. Little has been reported in the technical literature, on modern soaking practices and their relationship to the shift in our major raw material.
This paper compares contemporary soaking practices to historical methods, emphasizing those aspects that are widely acknowledged as critical for optimization of beamhouse chemistry. We examine current practice and challenge the commonly accepted measurements used to measure optimal soaking of fresh and brine cured hides. We reveal differences with respect to removal of the non-collagenous hide component, hyaluronic acid for various process chemistries on both fresh and cured cattlehides.Note de contenu : - Laboratory trials
- Tannery trials
- Measuring hyaluronic acidEn ligne : https://drive.google.com/file/d/1zjsmLf4xfH5PxoHGMziKvXxIUnrzaW9v/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39779
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIII, N° 3 (02/2008) . - p. 76-85[article]Réservation
Réserver ce document