University of North Florida
Browse the Citations

Contact Info

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

View Stuart Chalk's profile on LinkedIn


Classification: Industrial -> process liquor -> brine

Citations 2

"Flow Injection Fluorimetric Determination Of Traces Of Calcium In Brine"
Anal. Chim. Acta 1992 Volume 261, Issue 1-2 Pages 275-279
Hiroko Wada*, Hiromichi Atsumi and Genkichi Nakagawa

Abstract: The tetrapotassium salt (I) of N-2-8-[bis(carboxymethyl)amino]-6-methoxy-2-quinolyl-methoxy-p-tolyl-N-(carboxymethyl)glycine (Quin 2) was used, in 10 µM aqueous solution, as a reagent for the flow injection fluorimetry of calcium. The sample of 5 M brine (25 µL) was injected into 0.05 M PIPES - NaOH buffer of pH 6.8 to 7.0, and this solution was merged with the I solution before passage through a coil (1 m x 0.5 mm) maintained at 20°C. The fluorescence of the resulting solution was measured at 496 nm (excitation at 328 nm). The calibration graph (based on peak height for solution prepared in 5 M NaCl as matrix) was rectilinear up to 10 µM-Ca, and the coefficient of variation was 3.5% at 20 µg L-1 (n = 12); the detection limit was 3.4 µg l-1. Up to 0.1 mM Mg did not interfere; negative interference by Cu(II), Zn, Fe(III) and Al could be masked with nitrilotriacetic acid, but Sr and Ba caused positive errors. The method was applied to brine from the chlor - alkali process. 2-[(2-Amino-5-methylphenoxy)methyl]-6-methoxy-8-aminoquinoline- N,N,N',N'-tetraacetic acid (Quin 2) reacts with calcium ion to form a fluorescent complex (λ(ex) 328 nm, λ(em) 496 nm). Calcium in brine could be determined with Quin 2 in the presence of at least 25 mg L-1 magnesium with a simple flow injection system. Highly concentrated sodium chloride solution (~5 M) could be directly injected into the carrier containing 0.05 M piperazine-N,N'-bis(2-ethanesulfonic acid) (PIPES)-sodium hydroxide buffer. The relative standard deviation was 3.5% for 12 injections of 20 µg L-1 calcium. The detection limit of calcium was 3.4 µg L-1. The sensitivities were the same for samples not containing and containing sodium chloride. The method permits the determination of calcium in chlor-alkali brine.
Calcium Fluorescence Interferences Complexation

"Determination Of Bromide In Sodium Chloride Matrices By Flow Injection Analysis Using Blank Peak Elimination And Kinetic Discrimination"
Anal. Chim. Acta 1993 Volume 272, Issue 2 Pages 245-250
W. J. M. Emaus* and H. J. Henning

Abstract: The cited determination was based on oxidation of bromide to bromine using chloramine T, with subsequent reaction of the bromine with phenol red to give bromophenol blue which is measured spectrophotometrically at 590 nm. The FIA manifold used is illustrated (flow rates etc. given); short reaction times offered by FIA prevented the interference of chloride. The influence of peak blanks, which appear because of differences in refractive indices between the aqueous carrier solution and sample solution was eliminated by using a large sample volume The method was applied to the determination of 0.5 to 10 mg L-1 of bromide in NaCl solution (300 g l-1). The limit of quantification was 1.0 mg of Br kg-1 with a coefficient of variation of 1% at when determining 30 to 50 mg of Br kg-1. Analysis time was ~60 s. The method was applied to the analysis of brine used as starting material in the chlor-alkali industry.
Bromide Spectrophotometry Kinetic Interferences