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The effect of trypsin on soaking of salt cured hides / Luis A. Zugno in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), LXXXVII, N° 6 (06/1992)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > LXXXVII, N° 6 (06/1992) . - p. 207-220 Titre : The effect of trypsin on soaking of salt cured hides Type de document : texte imprimé Auteurs : Luis A. Zugno, Auteur Année de publication : 1992 Article en page(s) : p. 207-220 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Trypsin was biotinylated with NHS-biotin(N-hydroxysuccinimido biotin) and standard cattlehide soaking experiments were conducted in a TRIS buffer solution at pH 7.8 containing 0.02M of calcium ion. The experiments were performed in an equipment that provided temperature control and mechanical agitation; the flesh and grain sides of the hide were submitted to soaking,individually.The soaking time was 4 hours at 30°C. The biotinylated trypsin was detected inside the hide by the biotin-avidin peroxidase technique, and an insoluble dark brown polymer was formed after the oxidation of DAB(3,3'-diaminobenzidine).With the concentrations and experimental conditions used trypsin had limited penetration in the grain and flesh side and increased penetration in highly area.In the grain, epidermal-dermal separation was observed.Permeability and enzyme penetration increased by increasing the enzyme concentration,suggesting that better soaking and unhairing is obtained.Pieces treated with trypson in the grain produced leather with cleaner grain than was shown by the control. En ligne : https://drive.google.com/file/d/1DLAgUELv9ButhKKov1ItJuaNOjFgfpjS/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8288 [article]

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Fractionation of Cr and determination of Cr(VI) in blue shavings / R. Milacic in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), LXXXVII, N° 6 (06/1992)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > LXXXVII, N° 6 (06/1992) . - p. 221-232 Titre : Fractionation of Cr and determination of Cr(VI) in blue shavings Type de document : texte imprimé Auteurs : R. Milacic, Auteur ; Janez Stupar, Auteur ; Nevenka Kozuh, Auteur Année de publication : 1992 Article en page(s) : p. 221-232 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Blue shavings are a protein-based matrix with a high content of chromium(III) salts and organic polymers.If they contain excessive amounts of chromium(VI) they could be a potentially hazardous waste in the environment.Fractionation of chromium in blue shavings was studied by employing various sequential extraction procedures to determine the water soluble,exchangeable,organically bound,carbonate,crystalline, hydroxide and sulphide fractions.Chromium(VI) was determined in the phosphate buffer extractable(pH=6.5-7.0) fraction. Results obtained by several analytical techniques indicate limitations in the determination of Cr(VI).Ion-pairing reversed phase HPLC combined with flame or electrothermal AAS was found to be affected by severe matrix effects due to organic polymers in blue shavings and high salt concentrations in the buffer and extractant solutions.Chelating ion-exchange and ion-exchange chromatography combined with flame AAS detection gave over-estimated results due to inefficient retention of inert Cr(III) complexes.Spectrophotometry(addition of diphenylcarbazide reagent to the analyte prior to acidification) and extraction of Cr(VI)-HC1 complex into MIBK(277K) gave generally comparable and reliable results.The detection limit for the former technique was 2 ng cm(-3) and 15 ng cm(-3) for the latter.Our investigations indicate that over 90 percent of total chromium in blue shavings is in chemically inert form,approxymately 8 percent is extracted with Na4P2O7 while less than 0.003 percent exists in the toxic chromate form. En ligne : https://drive.google.com/file/d/1h15lkLO0eXXzNFGmURWR9ibxLcnpkr0t/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=8310 [article]

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