2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
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Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology<br />
P87 ThE FLuORIMETRIC DETERMINATION OF<br />
ALuMINIuM, GALLIuM AND INDIuM wITh<br />
8-hyDROxyQuINOLINE-5-SuLPhONIC ACID<br />
IN AQuEOuS AND SubMICELLAR MEDIuM<br />
ŠIMOn VOJTA and LUMíR SOMMER<br />
Institute of Environmental Protection, Faculty of Chemistry,<br />
Brno University of Technology, Purkyňova 118, 612 00 Brno,<br />
Czech Republic,<br />
halapaloosa@email.cz<br />
Introduction<br />
The complexing and analytical properties of 8-Hydroxyquinoline-5-sulphonic<br />
acid (QSA) are similar to 8-Hydroxyquinoline<br />
but the solubility of complexes in aqueous solutions<br />
increases and no fluorescence of the reagent in the large<br />
pH interval has been observed. The QSA was formerly used<br />
as a fluorogenic reagent for a number of metal ions including<br />
Mg 2+ , Zn 2+ , Cd 2+ , Ce 3+ and Al 3+ (ref. 1 ). The fluorimetry<br />
of Gallium and Indium complexes in aqueous solutions was<br />
only briefly mentioned.<br />
The fluorescence of metal complexes with QSA can be<br />
considerably enhanced in the presence of surfactants in submicellar<br />
and micellar medium 2,3 . The fluorescence properties<br />
of the metal species with QSA were tested in the presence<br />
of surfactants and exploited chromatographically in very low<br />
concentrations.<br />
Thus the cationic surfactants were widely used for the<br />
enhancement of fluorescence of metal complexes with QSA 4 .<br />
The attention was also paid to the fluorimetric determination<br />
of Al with QSA also in mixtures with Zn using derivative<br />
synchronous scan in the presence of surfactant 5 . The Partial<br />
Least Square Method (PLS) in combination with pH gradient<br />
FIA was used in binary mixtures of ions in complexes with<br />
QSA whose fluorescence was enhanced by the surfactant 6 .<br />
In this paper the fluorescent Al 3+ , Ga 3+ and In 3+ complexes<br />
with QSA were studied in detail in the absence and<br />
presence of surfactants and optimal conditions were recommended<br />
for the determination of particular metals in the presence<br />
of Zephyramine. normal and first derivative spectra<br />
were evaluated.<br />
Experimental<br />
I n s t r u m e n t s<br />
Spectrofluorimeter Aminco Bowman, Series 2 with<br />
1 cm quartz cells, 4 nm exit slits, photomultiplier under 450–<br />
850 V. Sample cell was tempered to 20 °C.<br />
The calculation of the first derivative was made by using<br />
the instrument software using Golay-Savitzky 11-point convolution.<br />
C h e m i c a l s<br />
Standards used, Analytica s.r.o., Prague:<br />
Aluminium chloride 1.000 ± 0.002 g dm –3 containing 5 % HCl<br />
Gallium chloride 1.000 ± 0.002 g dm –3 containing 10 % HCl<br />
Indium chloride 1.000 ± 0.002 g dm –3 •<br />
containing 10 % HCl<br />
s513<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
•<br />
8-Hydroxyquinoline-5-sulphonic acid hydrate (QSA),<br />
Sigma–Aldrich was used without purification<br />
0.1M Benzyldimethyltetradecylammonium chloride<br />
(Zephyramine ® ) – Sigma-Aldrich Co.<br />
0.1M 1-ethoxykarbonylpentadecyltrimethylammonium<br />
bromide (Septonex ® )–Sigma-Aldrich Co.<br />
0.1M Dodecylbenzyldimethylammonium bromide (Ajatin<br />
® ) – Sigma-Aldrich Co.<br />
1% Didodecyldimethylammonium bromide – Sigma-<br />
Aldrich Co.<br />
1% Polyoxyethylene(23) lauryl ether (Brij 35) – Sigma-<br />
Aldrich Co.<br />
1% Hexadecyltrimethylammonium chloride – Fluka.<br />
1% 4-(1,1,3,3-Tetramethylbutyl)phenyl-polyethylene<br />
glycol (Triton X-100) – Calbiochem Co.<br />
0.1 M Sodium dodecylsulphate (SDS) - BDH Chemicals,<br />
England.<br />
E v a l u a t i o n o f D a t a<br />
The limits of detection X D α and XD β calculated according<br />
to Graham 7 follow from the calibration plots and their<br />
confidence intervals were compared with those from multiple<br />
measurements of the background according to IUPAC 8 .<br />
The stoichiometry of complexes was evaluated by using<br />
the modified continuous variations method 9 in the absence<br />
and presence of cationic surfactant Zephyramine. The fluorescence<br />
was measured for several sums of equimolar solutions,<br />
where c o = c M + c L .<br />
Results<br />
The complexes of 8-Hydroxyquinoline-5-sulphonic acid<br />
with Al, Ga, and In produce an outstanding fluorescence for<br />
wavelengths over 430–600 nm with λ max at 495 nm for Al,<br />
λ max at 504 nm for Ga and λ max at 519 nm for In. The corresponding<br />
excitation λ max are 360 nm, 365 nm and 367 nm.<br />
The fluorescence shows considerable pH dependence which<br />
reaches the maximum in solution with c L = 7.4 × 10 –5 M<br />
Fig. 1. Excitation(a) and emission(b) spectra of Aluminium(III)<br />
in the presence of 7.4 × 10 –5 mol dm –3 QSA at 620 V in dependence<br />
on concentration of Al(III) at ph 4<br />
1 – 1.6 μg cm –3 , 2 – 0.8 μg cm –3 , 3 – 0.4 μg cm –3 , 4 – 0.2 μg cm –3 ,<br />
5 – 0.05 μg cm –3 , 6 – 0 μg cm –3