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
Website: @unf

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Organic compound

Classification: Organic compound -> toluene

Citations 2

"Enzymic Flow Injection Analysis In Non-aqueous Media"
Anal. Chem. 1992 Volume 64, Issue 2 Pages 129-133
Lorenzo Braco, Jose A. Daros, and Miguel De la Guardia

Abstract: The use of non-covalently immobilized enzyme reactors operated in non-aqueous media is described, with a co-immobilized cholesterol oxidase - horse-radish peroxidase reactor for flow injection spectrophotometric determination of cholesterol (I) in toluene as a model system. Reactors were prepared by adsorption of the biocatalyst on to controlled-pore glass beads and incorporated into a flow injection system. For determination of I, the carrier solution was H2O-saturated toluene containing 1 mM p-anisidine. Spectrophotometric detection was at 458 nm. Calibration graphs were rectilinear from 20 µM to 0.18 mM I. The detection limit was 1 µM I. A novel enzymatic flow injection approach is proposed, involving the use of non-covalently immobilized enzyme reactors operating in non-aqueous media. The feasibility of this approach was tested and successfully demonstrated by using as a model system a co-immobilized cholesterol oxidase-peroxidase reactor for the determination of cholesterol in toluene. The response was linear up to 1.8 x 10^-4 M cholesterol, with a detection limit of 10^-6 M. The throughput was 60 samples/h. The reactor was stable for >4 months with a half-life of 81 days. The strategy developed combines the remarkable benefits offered by enzymology in organic solvents and the advantages inherent in flow injection methods. Among them, the biocatalyst can be immobilized in a rapid, complete, and irreversible manner by simple adsorption to the solid support; poorly water-soluble compounds can be readily dissolved in the mobile phase and directly analyzed; and most importantly, the enzymatic reactor exhibits an enhanced stability in the water-restricted environment.
Cholesterol Spectrophotometry Immobilized enzyme Organic phase detection Controlled pore glass

"Simple Oxidative Pre-treatment For Determination Of Organomercury By Cold Vapor Atomic-fluorescence Spectrometry"
Microchim. Acta 1992 Volume 109, Issue 1-4 Pages 117-120
Wei Jian and Cameron W. McLeod

Abstract: For the direct determination of organomercury in toluene extracts, bromination was used to oxidize the organomercury compounds, and inorganic mercury ions were partitioned into the aqueous phase. A high H2O:toluene volume ratio (100:1) was used to avoid the need for phase separation. Aqueous extracts were quantified by flow injection - cold vapor AFS. The flow injection analyzer. consisted of a peristaltic pump, rotary injection valve, gas - liquid separator and atomic fluorescence detector at 253.7 nm. Flow rates for HCl and SnCl2 were 4 mL min-1. Recoveries for 2 µg L-1 of methylmercury additions to toluene were 100 to 106%.
Methylmercury ion Sample preparation Fluorescence Phase separator