University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Bauxite

Classification: Geological -> rock -> bauxite

Citations 2

"Spectrophotometric Determination Of Iron With Ferrozine By Flow Injection Analysis"
Talanta 1997 Volume 44, Issue 10 Pages 1793-1801
M. I. Pascual-Reguera*, I. Ortega-Carmona and A. Molina-Díaz

Abstract: Two methods for the determination of iron by normal FIA and reversed FIA were developed using sodium 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4',4''-disulfonate (ferrozine). The reagent formed a chelate with Fe(II) in hexamethylenetetramine buffered medium at pH 5.5. In one previous reaction coil Fe(III) was reduced to Fe(II) by ascorbic acid and in the other reaction coil the complexation reaction was developed. The linear range of the determination was 0.5-6 and 0.1-5 µg mL-1 of iron for normal FIA and reversed FIA respectively. The proposed method was sensitive (detection limit 0.012 and 0.010 µg mL-1), rapid and reproducible (RSD 0.3 and 0.28%). The method was satisfactorily applied to the determination of iron in waste water, toadstool tissue, potato leaves, human hair and bauxites at a sampling rate of 90 and 50 samples h-1 for normal FIA and reversed FIA respectively.
Iron Spectrophotometry Reverse Sensitivity

"Spectrophotometric Determination Of Titanium(IV) Using Chromotropic Acid And A Flow Injection Manifold"
Analyst 1992 Volume 117, Issue 7 Pages 1175-1177
Rajesh Purohit and Surekha Devi

Abstract: The pH, reagent concentration, sample volume, flow rate and reaction-coil length were optimized for the determination of µamounts of Ti(IV) in a flow injection manifold (described) with chromotropic acid (I) as the complexing agent and absorbance measurement at 443 nm. A rectilinear calibration graph was achieved in the range 50 µM to 0.47 mM Ti(IV) with use of 0.25% I solution (pH 5), a flow rate of 3 mL min-1 and a coil length of 10 cm; the limit of detection was 25 ng. Interference due to various cations was studied; that due to Al, Fe(II), Pb(II) and V(V) could be eliminated by using K oxalate, thiourea, Na2S2O3 and 1,10-phenanthroline, respectively, as masking agents. The method was used for the determination of Ti in bauxite. Microamounts of titanium(IV) were determined spectrophotometrically using a flow injection manifold and chromotropic acid as a complexing reagent. The various experimental conditions were optimized for the determination of titanium(IV) at 443 nm. Linear calibration was achieved over a titanium concentration. range of 5 x 10^-5 - 4.7 x 10^-4 mol L-1. The limit of detection of the proposed method was 25 ng. The method was applied to the determination of titanium in bauxite.
Titanium(IV) Spectrophotometry Optimization Complexation Interferences