Amino acid analysis by low pressure ion chromatography with conductivity detection / Hong Dai in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 5 (09-10/2004)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 88, N° 5 (09-10/2004) . - p. 197-201 Titre : Amino acid analysis by low pressure ion chromatography with conductivity detection Type de document : texte imprimé Auteurs : Hong Dai, Auteur ; Zhang Xinshen, Auteur ; Zhaoli Wang, Auteur ; Bing Li, Auteur Année de publication : 2004 Article en page(s) : p. 197-201 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acides aminés Les acides aminés (ou aminoacides) sont une classe de composés chimiques possédant deux groupes fonctionnels : à la fois un groupe carboxyle –COOH et un groupe amine –NH2. Parmi ceux-ci, les acides α-aminés se définissent par le fait que leur groupe amine est lié à l'atome de carbone adjacent au groupe acide carboxylique (le carbone α), ce qui leur confère la structure générique H2N–CHR–COOH, où R représente la chaîne latérale, qui identifie l'acide α-aminé. Les acides α-aminés jouent un rôle fondamental en biochimie comme constituants élémentaires des protéines : ils polymérisent en formant des liaisons peptidiques qui aboutissent à de longues chaînes macromoléculaires appelées peptides. Chimie analytique Chromatographie Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Automated amino acid analysis by low pressure ion chromatography separation and conductivity detection has been investigated. The method is characterized by separating amino acids under the low pressure of 1.97 - 2.94 x 10-5 Pa (30 - 40 psi) and detecting them by sensitive conductivity without pre-column or post-column derivatisation. The chromatography parameters were investigated, i.e. the capacity of the resin, the size of the resin, the length of separation column, elution solution and flow rate. The results show that 10 amino acids, Asp, Hyp, Ser, Glu, Pro, Gly, Ala, Val, Met and Leu have been separated and detected successfully using a 5mm x 100mm long column filled with 25μm - 30μm size and 0.02mmol/g capacity cationic exchange resin. The elution solution is 0.8mmol/L nitric acid solution and the flow rate 0.6ml/min. The method is linear in the concentration range of 10-3 - 10-4 mol/L and 10-4 - 10-5 mol/L. The variation coefficient is 1%-5% and the detection limit which can be achieved is 1.0 x 10-5 mol/L. Note de contenu : - EXPERIMENTAL PROCEDURE : Apparatus - Reagents - Preparation of amino acid solution - Mobile phase - RESULTS : Choice of separation column - Choice of the elution system - Study on the retention time of various kinds of amino acids - Separation experiment - Determination of accuracy - Linear range measurement and linear regression calculation - Determination of detection limits - Table 1 : Optimum chromatography parameters of amino acid analysis - Table 2 : Retention times of amino acids - Table 3 : Result of the accuracy experiment of amino acids analysis by LPIEC and conductivity detection - Table 4 : Result of linearity experiment of 10-3 - 10-4mol/L amino acids - Table 5 : Result of linearity experiment of 10-4 - 10-5 mol/L amino acids - Table 6 : Detection limits En ligne : https://drive.google.com/file/d/1YlHj4KHHmjgADuh5nAo71UU0NUWzG8ul/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39624 [article]

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Analysis of hydroxyproline in collagen of pigskin tissue by low pressure ion chromatography separation and conductivity detection / Hong Dai in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 89, N° 4 (07-08/2005)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 89, N° 4 (07-08/2005) . - p. 145-148 Titre : Analysis of hydroxyproline in collagen of pigskin tissue by low pressure ion chromatography separation and conductivity detection Type de document : texte imprimé Auteurs : Hong Dai, Auteur ; Zongcai Zhang, Auteur ; Subo Fan, Auteur ; Zhang Xinshen, Auteur Année de publication : 2005 Article en page(s) : p. 145-148 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Acides aminés Les acides aminés (ou aminoacides) sont une classe de composés chimiques possédant deux groupes fonctionnels : à la fois un groupe carboxyle –COOH et un groupe amine –NH2. Parmi ceux-ci, les acides α-aminés se définissent par le fait que leur groupe amine est lié à l'atome de carbone adjacent au groupe acide carboxylique (le carbone α), ce qui leur confère la structure générique H2N–CHR–COOH, où R représente la chaîne latérale, qui identifie l'acide α-aminé. Les acides α-aminés jouent un rôle fondamental en biochimie comme constituants élémentaires des protéines : ils polymérisent en formant des liaisons peptidiques qui aboutissent à de longues chaînes macromoléculaires appelées peptides. Chlorhydrique, Acide Chromatographie Collagène -- Analyse Cuirs et peaux -- Analyse Cuirs et peaux de porcs Hydrolyse Hydroxyproline Séparation (technologie) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : A simplified method has been developed to determine the hydroxyproline concentration in pigskin collagen. The sample was prepared by hydrolyzing pigskin tissue collagen for 24 hours overnight at 110°C in 6M/Lhydrochloride acid followed by determination by low pressure ion chromatography separation and conductivity detection without derivatization. Hydroxyproline was separated and detected successfully using a 5mm x 100mm long column filled with 25μm-30μm size and 0.02 mmol/g capacity cationic exchange resin. The elution solution was 0.8mmol/L nitric acid solution and the flow rate was 0.6ml/min. The concentration of the hydroxyproline sample was calculated by the five points work curve of standard stock solution. The result shows that the concentration of hyp in the sample was 3.16 ± 0.28 mmol/L. The RSD of the method was 4.63-8.97%. The recovery percentage of hyp added to the sample was 92.5-105.5%. Note de contenu : - EXPERIMENTAL METHODS : Reagents and chemicals - Apparatus - Optimum chromatography parameters - RESULTS AND DISCUSSION : Determination of amount of hydrochloric acid needed for amino acid hydrolysis - Sample preparation - Standard curve preparation - Determination of hydroxyproline in sample - Recovery test - Determination of accuracy - Table 1 : Optimum chromatography parameters of amino acid analysis - Table 2 : Relationship between concentration of hydroxyproline and peak height - Table 3 : Concentration of hydroxyproline in samples - Table 4 : Recovery percentage of the determination for Hyp - Table 5 : Result of accuracy experiment En ligne : https://drive.google.com/file/d/14NZOFmgg0hcKd7hJDWqB0iiZqROk8HAy/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39245 [article]

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Effects of a clean subcritical degreasing system on wool fibers / Qiao Xia in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVI, N° 5 (05/2021)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVI, N° 5 (05/2021) . - p. 162-167 Titre : Effects of a clean subcritical degreasing system on wool fibers Type de document : texte imprimé Auteurs : Qiao Xia, Auteur ; Yinxuan Wang, Auteur ; Zongcai Zhang, Auteur ; Hong Dai, Auteur Année de publication : 2021 Article en page(s) : p. 162-167 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation Dégraissage (nettoyage) Laine brute Pentane Le pentane est un alcane linéaire de formule C5H12. Le terme pentane désigne aussi par extension abusive17 les trois isomères C5H12 : le n-pentane, le 2-méthylbutane ou isopentane et le 2,2-diméthylpropane ou néopentane. Ces diverses molécules comportent toutes cinq atomes de carbone. Utilisations : Le pentane est un solvant couramment utilisé en chimie organique. Propriétés chimiques : Le pentane brûle dans l'air selon la réaction : C5H12 + 8O2 —> 5CO2 + 6H2O (Wikipedia) Stabilité thermique Thermogravimétrie Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : It makes sense to use environmentally friendly methods of degreasing in fur-making process. In this study, subcritical n-pentane was used to degrease wool fibers. Thermogravimetric analysis (TGA) was used to observe and analyze the properties of the subcritical n-pentane degreased wool fibers. The results showed that the thermal stability of the fibers increased. Fourier Transform Infrared (FTIR) spectroscopy was used to analyze the structural changes of macromolecular chains in wool fibers. It was found that when the pressure was higher than 0.4 MPa, the wool fibers underwent a conformational change with the α-helix changing to β-folding. If the pressure was as high as 0.6 MPa, the disulfide bonds in the wool fibers scale layer appeared to break. X-ray powder diffraction experiment was used to study changes in wool fiber aggregation morphology. It was demonstrated that the crystalline zone of wool fibers changed and the fibers index grew, from 22.89% to 30.19%. Field emission scanning electron microscopy and ultra-depth of field microscopy was used to analyze changes in the surface morphology of wool fibers. The results suggested that after the treatment, the wool fibers were not damaged and the impurities on the wool surface were reduced. Note de contenu : - EXPERIMENTAL : Materials - Sample preparation - The experimental process - CHARACTERIZATION TECHNIQUES : Degreasing rate - Change in thermal stability in wool - Structural changes in wool fibers macromolecular chains using Fourier Transform Infrared (FTIR) spectroscopy - Structural changes in the aggregation state of wool fibers ssing X-Ray powder diffraction - Morphological changes on the wool surface using Scanning Electron Microscopy and ultra-depth microscopy - RESULTS AND DISCUSSION : Effect of degreasing - Effect of subcritical n-pentane treatment on thermal stability of wool fibers - Effect of subcritical n-Pentane treatment on macromolecular chain structure of wool fibers - Table 1 : Infrared characteristic absorption band of wool fibers22 - Table 2 : Relative intensity of some characteristic peaks of wool fibers after subcritical n-pentane treatment at different pressure DOI : https://doi.org/10.34314/jalca.v116i5.4292 En ligne : https://drive.google.com/file/d/1OUz4ZlvKlN2y_DdhPCN1R7GO6Ej2Oyvu/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35759 [article]

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A fast method to determine trace chromium(III) ion in chrome tanning and chrome tanning waste / Zhaoli Wang in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 3 (05-06/2004)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 88, N° 3 (05-06/2004) . - p. 113-115 Titre : A fast method to determine trace chromium(III) ion in chrome tanning and chrome tanning waste Type de document : texte imprimé Auteurs : Zhaoli Wang, Auteur ; Zhang Xinshen, Auteur ; Hong Dai, Auteur ; Yajun Luo, Auteur Année de publication : 2004 Article en page(s) : p. 113-115 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Chimie -- Essais et réactifs Chimie analytique Chrome trivalent -- Oxydation Ions chrome Tannage -- Déchets Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Large amounts of chromium (III) ion interfere with the determination of trace amounts of chromium (VI) ion in chrome tanning agents. Therefore, a new method was proposed for determination of trace chromium (III) in chrome tanning products and chrome tanning wastes by automatic reference flow injection. After chromium (III) is oxidised to chromium (VI) by potassium periodate, it can be determined by the flow injection function of an automatic metallic elements analyzer using diphenyl carbazide as the colour developing reagent and potassium periodate as the oxidant solution. The effect of the concentration of potassium periodate and the length of the reaction coil were investigated. Under the optimum conditions, the linear range and RSD of the method were 1.00-100ug/ml and 0.84% respectively. The method was applied to the analysis of chrome powder with recoveries ranging from 95.0% to 103.0%. The results satisfy the requirements of the determination. Note de contenu : - EXPERIMENTAL PROCEDURE : Chemical reagents - Apparatus - Preparation of solutions - Analytical procedure - Preparation of the samples - RESULTS AND DISCUSSION : Choice of the absorption wavelength - Choice of length of reaction coil - Choice of oxidant solution - Test of linearity and precision - Recovery tests and analysis of the samples - Analysis of coexisting Chromium (III) ion and Chromium (VI) ion - Table 1 : Precision test - Table 2 : Recovery percentage of Chromium (III) ion - Table 3 : Analytical resuls of samples En ligne : https://drive.google.com/file/d/169F8rw7HgmbKSDJz-yOYpO93MUp5fRjS/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39638 [article]

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Study on the degreasing of sheep skin using subcritical fluid extraction / Qiao Xia in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVI, N° 2 (02/2021)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVI, N° 2 (02/2021) . - p. 39-45 Titre : Study on the degreasing of sheep skin using subcritical fluid extraction Type de document : texte imprimé Auteurs : Qiao Xia, Auteur ; Zhang Meina, Auteur ; Bo Mao, Auteur ; Hong Dai, Auteur ; Zongcai Zhang, Auteur Année de publication : 2021 Article en page(s) : p. 39-45 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Caractérisation Cuirs et peaux -- Analyse Cuirs et peaux -- Dégraissage Cuirs et peaux de moutons Extraction (chimie) Peau -- Histologie Peaux brutes Pentane Le pentane est un alcane linéaire de formule C5H12. Le terme pentane désigne aussi par extension abusive17 les trois isomères C5H12 : le n-pentane, le 2-méthylbutane ou isopentane et le 2,2-diméthylpropane ou néopentane. Ces diverses molécules comportent toutes cinq atomes de carbone. Utilisations : Le pentane est un solvant couramment utilisé en chimie organique. Propriétés chimiques : Le pentane brûle dans l'air selon la réaction : C5H12 + 8O2 —> 5CO2 + 6H2O (Wikipedia) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Degreasing is one of the important processes for the production of leather and fur. This study aimed to develop a degreasing method using subcritical n-pentane. Sheep skin was chosen as raw skin for this investigation. The best possible combination of degreasing parameters was found using single factor experiment and response surface methodology. The effects of temperature and pressure on the degreasing efficiency were evaluated further with histological analysis. The results showed that the optimum degreasing parameters were a degreasing time of 58 min, pressure of 0.45 MPa, temperature of 41.0°C and thus yielded a degreasing rate of 52.46％ theoretically and 51.46% experimentally. Histological sections showed that the degreasing effect of subcritical n-pentane was quite significant and the lipid droplets around the hair follicles were dramatically reduced. It has been proven that subcritical n-pentane degreasing is an effective technique for sheep skin degreasing. Note de contenu : - EXPERIMENTAL : Materials & instruments - Experiment procedure - Sample preparation - Degreasing with subcritical n-pentane extraction - Single factor experiment design of subcritical n-pentane degreasing process - Optimization design of subcritical n-pentane degreasing process by RSM - Characterization of degreasing effect - Histological analysis of degreased skin - RESULTS AND DISCUSSION : Effect of degreasing - Table 1 : Single factor experiment scheme - Table 2 : Factor table for single factor experiment - Table 3 : Response surface experiment level and coding - Table 4 : Experimental scheme of response surface methodology and response value of degreasing rate - Table 5 : Analysis of variance of regression model of subcritical n-pentane degreasing - Fig. 1 : The sheep skin degreasing procedure with subcritical n-pentane - Fig. 2 : Single factor results - Fig. 3 : Residuals - Fig. 4 : Response surface graph and contour map - Fig. 5 : Histological photomicrographs of degreased skin under different temeprature - Fig. 6 : Histological photomicrographs of degreasing skin under different pressure DOI : https://doi.org/10.34314/jalca.v116i2.4234 En ligne : https://drive.google.com/file/d/1fFEfsYfERS70jjgP-KtN7vOTfnm400QO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35307 [article]

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Study on the degreasing of sheepskin by subcritical CH2Cl2 / Shanshan Yu in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 105, N° 2 (03-04/2021)  

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The effect of fatliquor emulsion on the physical properties of resultant leather / Zongcai Zhang in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 3 (05-06/2004)  

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