University of North Florida
Browse the Citations
-OR-

Contact Info

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

View Stuart Chalk's profile on LinkedIn

Food

Classification: Food -> honey

Citations 10

"A Continuous Spectrophotometric System For The Discrimination/determination Of Monosaccharides And Oligosaccharides In Foods"
Anal. Chim. Acta 2000 Volume 404, Issue 1 Pages 121-129
A. Cáceres, S. Cárdenas, M. Gallego and M. Valcárcel

Abstract: A simple, rapid method for the spectrophotometric discrimination of monosaccharides from the oligosaccharide fraction of fruit juice, jam, syrup and honey samples is proposed. The sample, in alkaline medium, is directly introduced into a flow system and passed through an activated carbon column for its decolorization; then, a volume of 200 µl is injected into the derivatising reagent stream to start the analytical reaction, which takes place at 85°C. The two fractions are discriminated on the basis of the different colors of the derivatives formed; thus, the derivatives of the monosaccharides are yellow while those of the di- and trisaccharides are violet-carmine. The two fractions are monitored at 400 and 540 nm, respectively. Sucrose gives no reaction as it is a non-reducing sugar. The proposed method allows reducing sugars contents from 0.01% to 0.80% w/v to be determined with an average relative standard deviation of 4.5% and a sampling frequency of 10 h-1. The proposed method was validated by applying it to two milk-based and sugar candidate artificial CRMs, with good correlation. The detection limits achieved (0.01% w/v for maltose, lactose and maltotriose at 540 nm) allow adulteration of fruit juices with high fructose syrup from starch at the 4% level to be detected.
Monosaccharides Oligosaccharides Maltose Lactose Maltotriose Spectrophotometry Reference material Heated reaction Activated carbon Column

"Amperometric Flow Injection Determination Of Fructose In Honey With A Carbon Paste Sensor Based On Fructose Dehydrogenase"
Anal. Chim. Acta 1996 Volume 330, Issue 1 Pages 71-77
Josefina Parelladaa, Elena Domíngueza,*, and Victor M. Fernándezb

Abstract: A carbon paste electrode modified 1% polyethyleneimine and pyrrolo quinoline quinone-fructose dehydrogenase (300 iu enzyme/100 mg grap) was employed at 400 mV vs. Ag/AgCl (0.1 M KCl) with a Pt wire counter electrode in a FIA system for determining fructose. The carrier stream (1 ml/min) was 0.1 M acetate buffer at pH 5 and the injection volume was 20 µL. A linear calibration graph was produced for 0.5-10 mM fructose, the detection limit was 75 µM and the RSD (n = 15) for 10 mM fructose was 1.6%. The system was used to determine fructose in honey. Honey samples of 10 g were extracted with 100 mL 0.1 M acetate buffer at pH 5 for 15 min at 60°C. The filtrate was diluted 25-fold with the same buffer and 20 µL portions were analyzed. The results were confirmed by LC with refractive index detection.
Fructose Amperometry Electrode Electrode Sample preparation Sensor Buffer Method comparison

"Continuous-flow Chemiluminometric Determination Of Tetracyclines In Pharmaceutical Preparations And Honey By Oxidation With N-bromosuccinimide"
Analyst 1993 Volume 118, Issue 6 Pages 633-637
Stergios A. Halvatzis, Meropi M. Timotheou-Potamia and Antony C. Calokerinos

Abstract: A continuous-flow-chemiluminometric method for determining tetracycline (I), oxytetracycline (II), doxycycline (III) and chlortetracycline (IV) and demeclocycline (V) in pharmaceutical preparations and honey is described. It is based on the chemiluminescence produced by the action of N-bromosuccinimide on tetracyclines in alkaline solution The calibration graphs were rectilinear from 0.05 to 3.0, 0.5 to 5.0, 0.5 to 7.0, 0.5 to 7.0 and 0.3 to 3.0 µg mL-1 of I, II, III, IV and V, respectively. The corresponding detection limits were 0.005, 0.4, 0.23, 0.22, 0.002 µg mL-1. Recoveries of 95.2 to 103.7 and 89.2 to 106.6% were obtained for commercial pharmaceutical preparations and honey samples, respectively. Coefficients of variation were 5% for both honey and the pharmaceuticals. There was no interference from common excipients.
Tetracycline Oxytetracycline Doxycycline Chlorotetracycline Demeclocycline Chemiluminescence Interferences

"Simultaneous Kinetic Spectrophotometric Determination Of 2-furfuraldehyde And 5-hydroxymethyl-2-furfuraldehyde By Application Of A Modified Winklers Method And Partial Least-squares Calibration"
Analyst 1995 Volume 120, Issue 10 Pages 2567-2571
Isabel Durán Merás, Anunciación Espinosa Mansilla and Francisco Salinas López

Abstract: A method is described for the simultaneous determination of 2-furfuraldehyde and 5-hydroxymethyl-2-furfuraldehyde; based On their reaction by a modified Winkler's method. A comparative study of the results found using the kinetic curves registered at 550 and 585 nm, as analytical signals, has been performed, The data set of the kinetic curves at 550 nm was selected as the analytical signal, Partial least squares (calibrating for a single chemical constituent at a time: PLS-1) multivariate calibration was then applied for the determination, The proposed method was satisfactorily applied to the analysis of wines, spirits, fruit juices and honey. (31 references)
2-Furaldehyde 5-Hydroxymethyl-2-furaldehyde Spectrophotometry Spectroscopy Calibration Kinetic Multicomponent Multivariate calibration Partial least squares

"Flow Injection Determination Of HMF [5-hydroxymethylfurfural] In Honey By The Winkler Method"
Fresenius J. Anal. Chem. 1991 Volume 340, Issue 4 Pages 250-252
F. Salinas, A. Espinosa Mansilla, and J. J. Berzas Nevado

Abstract: Honey (~10 g) was dissolved in water (50 ml), the solution was filtered and the filtrate (150 µL) was injected into the carrier stream (H2O) of a flow injection system (described with diagram). The stream was mixed sequentially with aqueous 10% p-toluidine (Winkler reagent) and barbituric acid solution and passed through a mixing coil. The absorbance was measured at 550 nm; first derivatives were also calculated by computer. The calibration graph was rectilinear up to 98 µg g-1 of HMF and the coefficient of variation (n = 10) was ± 3 and ± 2.4% at 3.8 µg mL-1 of HMF for the conventional and first derivative methods, respectively. Sampling frequency was 35 h-1; furfuraldehyde interfered.
Furfural Spectrophotometry Spectroscopy Computer Filter Interferences

"Digestion-free Determination Of Heavy Metals In Honey Using Anodic-stripping Differential Pulse Voltammetry And Potentiometric-stripping Analysis"
Fresenius J. Anal. Chem. 1995 Volume 351, Issue 7 Pages 678-682
Yingjian Li, Faramarz Wahdat and Rolf Neeb

Abstract: Experiments have been carried out to assess the potential of differential pulse voltammetry and potential stripping analysis for determining Pb, Cu and Cd directly in dissolved honey samples using a flow-through cell. With the hanging mercury drop electrode Pb alone can be determined only if the electrode is first modified in-situ with Triton X 100 to increase the separation between the Pb peak and a broad, interfering adsorption peak which overlaps the Cu peak. If the (more sensitive) thin film mercury electrode is used the interference encountered is less so also Cu and Cd can be determined. With potentiometric stripping analysis Cu and Pb can be determined using normal procedures. The determination of Cd, however, can only be carried out if the concentration of the oxidizing agent [Hg(II)] in solution is decreased. A good agreement has been obtained between the values found and those obtained after high pressure digestion of the samples.
Cadmium Copper Lead Metals, heavy Potentiometric stripping analysis Voltammetry Voltammetry

"Studies On Reducing Sugar In Honey By Flow Injection Spectrophotometry"
Gaodeng Xuexiao Huaxue Xuebao 1998 Volume 19, Issue 12 Pages 1925-1928
Xu, H.Y.;Wang, K.M.

Abstract: Based on lowering the temperature and shortening the time of reaction between the reducing sugar and K3[Fe(CN)6], a flow injection spectrophotometry for the high content reducing sugar in honey was established. In comparison with titration and flow injection spectrophotometry, the latter is more convenient and rapid. The sampling frequency is 70 ~ 80 times per h. Using the method to determine some honey, the results were satisfactory.
Sugars, reducing Spectrophotometry Method comparison

"Semiautomatic Determination Of Furanic Aldehydes In Food And Pharmaceutical Samples By A Stopped-flow Injection Analysis Method"
J. AOAC Int. 1993 Volume 76, Issue 6 Pages 1255-1261
Espinosa Mansilla, A.;Munoz De La Pena, A.;Salinas, F.

Abstract: Sample solution was injected into a carrier stream of water which merged sequentially with a stream of 5 M HCl and a stream of 0.03 M 2-thiobarbituric acid. The procedure was carried out at 40°C and the reaction was monitored at 425 nm. A schematic diagram of the stopped-flow FIA system is presented. The method was used to determine 5-hydroxymethyl-2-furfuraldehyde (I) and furfural in honey, orange and grape juice, red wine and pharmaceuticals. The calibration graph was linear for 1.1-14.6 µg/ml of I and the detection limit was 0.47 µg/ml. The RSD for 5.6 µg/ml of I (n = 10) was 2.4%. Sample throughput was ~40/h; details are given of the manual and automatic steps of the procedure. A kinetic study of the reactions of 5-hydroxymethyl-2-furfuraldehyde and furfural with 2-thiobarbituric acid (TBA) by a stopped-flow flow injection analysis technique has been undertaken. A semiautomatic method for the analytical determination of these furanic aldehydes is proposed on the basis of reaction with TBA. The proposed stopped-flow method was successfully applied to several commercial pharmaceutical preparations and food samples. The procedure is faster than the earlier procedure for determination of these compounds in foods and pharmaceuticals.
Aldehydes, furanic Spectrophotometry Stopped-flow Kinetic

"Characterization Of Honey From The Canary Islands: Determination Of The Mineral Content By Atomic Absorption Spectrophotometry"
Food Chem. 2005 Volume 93, Issue 3 Pages 449-458
O.M. Hernández, J.M.G. Fraga, A.I. Jiménez, F. Jiménez and J.J. Arias

Abstract: In this work, different types of honey produced in the Canary Islands were characterized on the basis of their mineral contents. Overall, 10 metals were determined in 116 samples, 81 of which were from the Canaries and 35 from various other places. Iron, copper, zinc, magnesium, calcium and strontium were determined by atomic absorption spectrophotometry, and potassium, sodium, lithium and rubidium by atomic emission spectrophotometry. A flow injection manifold was employed to analyze those samples requiring dilution. The chemometric processing of the spectroscopic results by various techniques (including principal component analysis, cluster analysis, discriminant analysis and logistic regression) allowed the accurate classification of the honey samples according to origin.
Iron Copper Zinc Magnesium Calcium Strontium Potassium Sodium Rubidium Lithium Spectrophotometry Spectrophotometry Chemometrics Principal component analysis

"Flow Injection Analysis Of Tetracyclines Using Inhibited Ru(bpy)32+/tripropylamine Electrochemiluminescence System"
Luminescence 2005 Volume 20, Issue 1 Pages 8-15
Yong-Qiang Pang, Hua Cui*, Hai-Song Zheng, Guo-Hui Wan, Li-Juan Liu, Xiao-Feng Yu

Abstract: Tetracyclines (TCs) were found to strongly inhibit the electrochemiluminescence (ECL) from the Ru(bpy)32+-tripropylamine system when a working Pt electrode was maintained at 1.05 V (vs. Ag/AgCl) in pH 8.0 carbonate buffer solution. On this basis, a flow injection (FI) procedure with inhibited electrochemiluminescence detection has been developed for the determination of tetracycline (TC) and oxytetracycline (OTC). Under the optimized condition, the linear ranges of 2.0 x 10^-8-1.0 x 10^-5 and 1.0 x 10^-8-1.0 x 10^-5 g/mL and the detection limits of 4.0 x 10^-9 and 3.8 x 10^-9 g/mL were obtained for TC and OTC, respectively. The relative standard deviations (RSD) were 0.68% and 1.18% for 5.0 x 10^-7 g/mL TC and OTC (n = 13), respectively. The method showed higher sensitivity than most of the reported methods. It was successfully applied to the determination of tetracycline in a Chinese proprietary medicine, Tetracyclini and Cortisone Eye Ointment, and the residues of tetracycline in honey products. The inhibition mechanism has been proposed due to an energy transfer between electrogenerated Ru(bpy)32+* and benzoquinone derivatives at the electrode surface.
Tetracycline Chemiluminescence Electrode Optimization Sensitivity