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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Food

Classification: Food -> coffee

Citations 3

"Post-chromatographic Derivatization And Detection Techniques For The Characterization Of Element Binding Types In Coffee And Tea"
Fresenius J. Anal. Chem. 1983 Volume 316, Issue 6 Pages 594-599
G. Weber und G. Schwedt

Abstract: Organic complexes of Cu, Zn and Fe present in coffee and tea were extracted into ethyl acetate and then determined by reversed-phase HPLC Both u.v. and conductivity detectors were used, and continuous-flow systems were developed for chemical derivatization of, e.g., phenols, amines, thiols, aromatic amines and carbonyl compounds. Zinc and Fe were determined by AAS (air - acetylene flame), and Cu was determined by flameless AAS Phenolic compounds, particularly flavonoids, were shown to be important as binding agents for the metals in tea.
Copper Iron Zinc HPLC Conductometry Spectrophotometry Complexation

"Trapping System For Trace Organic Volatiles"
J. Chromatogr. A 1991 Volume 586, Issue 2 Pages 315-322
Tomás Jursík, Karel Stránský* and Karel Ubik

Abstract: A technique is described for the collection and concentration of volatile compounds produced by plants, animals and other materials which is a modification of the continuous-flow system based on absorption of volatiles in a low amount of solvent at low temp (cf. 'Proceedings of a Conference on Insect Chemistry and Ecology Tabor, Aug 12-18, 1990', Hrdy (Ed.), Academia, Prague, 1991, p.327). The trapping device (illustrated) works offline and the concentrated analytes are analyzed by GC (details given). The method was evaluated in the analysis of C8 to C22 alkanes and subsequently applied in the analysis of coffee beans, spruce bark, black pepper, beer and PVC floor covering. Chromatographs are presented. The advantages and disadvantages of the trapping device are tabulated.
Organics, volatiles GC C8 Apparatus

"Quality Control Of Roasted Coffee Beans With FIA System For Chemiluminescent Determination Of Low Concentrations Of Hydrogen Ions"
Bunseki Kagaku 1989 Volume 38, Issue 3 Pages T35-T39
Ishii, M.;Baba, T.;Yamada, M.

Abstract: The method was based on measurement of chemiluminescence generated by the reaction of H+ with didodecyldimethylammonium bromide - NaOH - eosin Y (C. I. Acid Red 87). The calibration graph was rectilinear for 6.8 µM to 2.5 mM H+. In the determination of 8.3 µM-H+, the coefficient of variation (n = 10) was 1.1%. The method was based on measurement of chemiluminescence generated by the reaction of H+ with didodecyldimethylammonium bromide - NaOH - eosin Y (C. I. Acid Red 87). The calibration graph was rectilinear for 6.8 µM to 2.5 mM H+. In the determination of 8.3 µM-H+, the coefficient of variation (n = 10) was 1.1%.
Acidity Chemiluminescence