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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Classification: Fruit -> apple

Citations 3

"Characterization Of Apple Cider Cultivars By Chemometric Techniques Using Data From High-performance Liquid Chromatography And Flow Injection Analysis"
Analyst 1998 Volume 123, Issue 6 Pages 1187-1191
D. Blanco-Gomis, I. Herrero-Sánchez and J. J. Mangas Alonso

Abstract: Anal. techniques (HPLC and flow injection anal.) for determining sugars, organic acids, polyphenols and pectins in apples, were employed along with chemometrics in the ripening and classification studies of cider apples. The use of principal component anal. allowed the authors to reduce the dimensionality of the data matrix; three new variables were obtained that accounted for 76% of variance. The projection of the apple cultivars in the reduced space allowed us to visualize the data structure on the basis of the degree of ripening and technol. characteristics of the cider apple varieties monitored. Linear discriminant anal. computed a canonical variable with a prediction capacity of 93%, using three groups for cancellation in order to validate the method. The use of modeling techniques, such as SIMCA and partial least squares made an adequate grouping of apple cultivars feasible on the basis of their degree of ripening.
Sugars Acids, organic Polyphenols Pectins HPLC Chemometrics

"Flow Injection Spectrofluorimetric Determination Of Ethylenethiourea"
Fresenius J. Anal. Chem. 1998 Volume 362, Issue 4 Pages 399-403
Tomás Pérez-Ruiz, Carmen Martínez-Lozano, Virginia Tomás, Antonio Sanz, Jesús Martín

Abstract: A flow injection configuration is proposed for the fluorimetric determination of ethylenethiourea. The procedure is based on the inhibitory effect of ethyl-enethiourea on the oxidation of thiamine to thiochrome by Hg(II). A linear calibration graph was obtained between 0.1-2.0 µg mL-1, with a sampling rate of 40 samples/h and a relative standard deviation of 1.11%. The usefulness of the method was tested for the determination of ethylenethiourea residues in water, milk, potatoes, pear, grape, and apple.
Ethylenethiourea Fluorescence Indirect

"Catalytic Photometric Method For The Determination Of Molybdenum In Plants With Flow Injection Analysis"
Proc. Natl. Sci. Counc. 1984 Volume 8, Issue 2 Pages 85-92
Lu, K.L.;Chen, Y.M.

Abstract: A fast routine analysis method for the determination of microgram amounts of Mo in plant samples was studied with flow injection analysis Based on detection by the catalytic effect of Mo for the liberation of I from iodides by peroxide; highly reproducible, sensitive, and accurate results can be obtained. Relative standard deviations of 0.8% and 1.7%, respectively, were obtained for the determination of 1.0 ppm and 0.1 ppm of Mo, at a rate of 90 samples per h. The Mo contents of the plant samples of mango, guava, and apple were determined with this method. By applying the standard addition method for the elimination of matrix influences, the Mo contents of 0.58, 0.83, and 0.48 ppm per g of dry sample were obtained for mango, guava, and apple, respectively, and the detection limit of 0.004 ppm was calculated (SFS)
Molybdenum Spectrophotometry Catalysis