Fluorometric Determination of Trace Amounts of Fluoride Ion Using an Expanded Porphyrin

✍ Scribed by M. Tabata; K. Kaneko; Y. Murakami; Y. Hisaeda; H. Mimura

• Book ID: 102615218
• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 379 KB
• Volume: 49
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1994.1021

✦ Synopsis

A highly selective and sensitive method of fluorometry is described for determination of the fluoride ion at the parts per billion level via the ion-pair complex formation of the fluoride ion with an expanded prophyrin [2,23-diethyl-8,17-bis(2-ethoxycarbonylethyl)(3,7,12,13,18,22)-hexamethylsapphyrin ( (\mathrm{H}_{3}) sap) ()). The ion-pair complex gives out an enhanced fluorescence intensity at (680 \mathrm{~nm}) on excitation at (450 \mathrm{~nm}). Since the present method is based on a direct reaction of the fluoride ion with the sappyrin, a 200 -fold amount of the aluminum (III) ion (\left[10^{-4} M\left(M=\mathrm{mol} \mathrm{dm}{ }^{-3}\right)\right]) and a 2000 -fold amount of the iron(III) ion (\left(10^{-3} M\right)) over the fluoride ion did not interfere with determination of the fluoride ion at concentrations as low as (5 \times 10^{-7} M) in the presence of 1,2-diaminocyclohexane- (N, N, N^{\prime}, N^{\prime})-teraacetic acid. The proposed method was applied to determination of the fluoride ion in various water samples (tap water, river water, rain water, underground water, and hot spring water) and satisfactory results were obtained. e 1994 Academic Press. Inc.