Determination of Tannins in White Wines by Thermal Lens Spectrometry

✍ Scribed by A. Claderaforteza; C. Tomasmas; J.M. Estelaripoll; V. Cerdamartin; G. Ramisramos

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 210 KB
• Volume: 52
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1995.1063

✦ Synopsis

Tannins in white wines were determined by reduction of the Folin-Ciocalteu reagent, extraction of the phosphomolybdenum blue produced into chloroform in the presence of a tetraalkylammonium salt, and thermal lens spectrometry (TLS). The TLS setup was pumped with a diode-array laser ((60 \mathrm{~mW}, 818 \mathrm{~nm})), and the thermal lens effect was probed with a (\mathrm{He}-\mathrm{Ne}) laser in a crossed-beam configuration. Extraction was quantitative within the range (25-250 \mathrm{ng} \mathrm{ml}^{-1}) gallic acid. Owing to the low limit of detection ( (5 \mathrm{ng} \mathrm{ml}^{-1}) gallic acid), sample dilution factors as large as 1:20,000 could be used, but the interference produced by (\mathrm{SO}_{2}) was not reduced. 1995 Academic Press, Inc.