Fluorometric reagent

Spectrophotometric and fluorometric reagents, once used extensively for deterrnination of beryUium (26,27), are seldom employed. Reviews of beryUium analysis are avaUable (15—17,24—30). 

In the search for new fluorometric reagents for trace metal determinations, ferroin-type compounds, namely 2-(2-pyridyl)-2//- and 2-(3-isoquinolyl)-3//-imidazo[4,5-/i]quinolines, and their silver, lead, and zinc chelates were tested for luminiscence in aqueous ethanol solutions at various pH values (80TAL1021). 

Diehl, H. "Calcein, Calmogite and o,o dehydroxyazobenzene titrimentrlc, colorimetric and fluorometric reagents for calcium and mangnesium", G. F. Smith Chemical Co. Columbus, Ohio,1964. 

The most successful fluorometric reagents for c.ition analyses have aromatic structures with two or more donor functional groups that permit chelate formation with the metal ion. The structures of four common reagents are shown in Figure I5-I. >. 

Selected fluorometric reagents and their ttpplica-tions are presented in Fable 15-2. As can be seen, liin-ils of detection (LODs) are quite low by most of these methods. 

Table 9.2. Selected Fluorometric Reagents for the Determination of Aluminum... 

A fluorometric analysis results in the collection of two spectra, the excitation spectrum and the emission spectrum. The excitation spectrum should be the same as the absorption spectrum obtained spectropho tome trie ally. Differences may be seen due to instrumental factors, but these are normally small, as seen in Fig. 5.45, which shows the absorption and excitation spectra for Alizarin garnet R, a fluorometric reagent for aluminum ion and fluoride ion. The longest wavelength absorption maximum in the excitation spectrum is chosen as the excitation wavelength this is where the first monochromator is set to excite the sample. It would seem reasonable to choose the wavelength that... 

Name two fluorometric reagents. What are the structural characteristics that make a molecule fluoresce ... 

For a more detailed diseussion of fluorometric reagents, see pp. 3S4 -426 of Molecular Luminescence Spet trosc(>p (noic ll). and ( Ouilbauli, in Comprehensive Analytical Chemistry. G. Svehla, cd.. Vol. VIII, Chap. 2. pp. 167-78, New York Elsevier, 1977... 

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