[article]
| Titre : |
Measurement of hexavalent chromium in chrome-tanned leather : comparative study of acidic condition extraction with alkaline extraction |
| Type de document : |
texte imprimé |
| Auteurs : |
Koki Ogata, Auteur ; Yuki Kumazawa, Auteur ; Yoichi Koyama, Auteur ; Keiji Yoshimura, Auteur ; Koji Takahashi, Auteur |
| Année de publication : |
2015 |
| Article en page(s) : |
p. 293-296 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Analyse quantitative (chimie)
Bases (chimie)
Cuir -- Teneur en chrome hexavalent
Extraction (chimie)
Oxydoréduction
pH -- Mesure
Statistique
|
| Index. décimale : |
675.2 Préparation du cuir naturel. Tannage |
| Résumé : |
Hexavalent chromium (Cr)E causes dermatitis and cancer, and is often quantified from chrome-tanned leather. Analysis for Cr6+ is generally carried out after extraction into 0.1 M potassium phosphate buffer (P-buffer pH8.0) according to the method of ISO 17075. However, since the pH value of chrome-tanned leather and sweat due to wear are on the acidic side, the abovea method for Cr6+ should be validated using acidic extracts. In the present study, acidic extracts from chrome-tanned leather were analyzed for Cr6+ comparing the results with those using alkaline extracts.
A sample of commercial chrome-tanned leather was used to investigate the influence of pH an the extractability of Cr6+. Chromium was extracted from the leather with P-buffer (pH3.0-11.0), acidic artificiel perspiration (pH5.5) or 0.2% sodium sulfate (pH5.5). The contents of total chromium (Cr) and Cr6+ in each extract were respectively measured by inductive coupled plasma atomic emission spectroscopy and colorimetry with diphenylcarbazide. Less Cr was extracted in the range of pH5.5-8.0, whereas more Cr was extracted in the more acidic and alkaline regions. By contrast, the amount of Cr6+ extracted increased moderately with increasing pH. When the P-buffer extract (pH8.0) was adjusted to pH3.0-11.0, the amount of Cr6+ increased with increasing pH, suggesting occurrence of a reversible conversion between Cr6+ and Cr3+. The extraction with P-buffer (pH8.0) may thus pravide a falsely high value due to this conversion. P-buffer (pH5.5) showed a significantly higher extraction of than tests with artificiel perspiration (pH5.5) and 0.2% sodium sulfate (pH5.5). The residue remaining after each extraction was re-extracted with a fresh aliquot of the appropriate extractant. The amount of Cr6+ in the second extract with P-buffer (pH5.5) exhibited a Iow extractability (about 9% of the amount of the first), whereas artificiel perspiration (pH5.5), 0.2% sodium sulfate (pH5.5), and P-buffer (pH 8.0) showed a high extractability (about 41-67% of the amount of the first). lt is thus concluded that extracting with P-buffer (pH5.5) is most efficient of the tested extractants for analyzing Cr6+ from chrome-tanned leather. |
| Note de contenu : |
- Materials
- Extraction of chromium for the leather sample
- Measurement of the redox potential of the extract
- Analytical methods
- Statistical analysis |
| En ligne : |
https://drive.google.com/file/d/1dCAAo1C3S3vOZgMvheWua20AaoPSaNgW/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=25102 |
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 99, N° 6 (11-12/2015) . - p. 293-296
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Measurement of hexavalent chromium in chrome-tanned leather : comparative study of acidic condition extraction with alkaline extraction in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 99, N° 6 (11-12/2015)
