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: Agricultural -> grain -> flour

Citations 6

"Determination Of Potassium Bromate In Flour By Flow Injection Analysis"
Analyst 1987 Volume 112, Issue 2 Pages 137-139
Brian G. Osborne

Abstract: Flour (5 g) was shaken with 20 mL of ZnSO4 solution (20 g l-1), then 4 mL of NaOH solution (21 g l-1) and 1 mL of water were added. The mixture was shaken for 5 min, and then centrifuged and filtered. Potassium bromate in the filtrate was determined by photometric flow injection analysis based on its reaction with acidified KI and starch. Response was rectilinear from 0.5 to 5.0 mg L-1 and recovery was 90%. The method was compared with a titration method. Analysis of eight samples in 15 min is possible by this method.
Bromate Spectrophotometry Sample preparation Tecator Extraction Method comparison

"Simultaneous Spectrofluorimetric Determination Of Selenium(IV) And (VI) By Flow Injection Analysis"
Analyst 1997 Volume 122, Issue 3 Pages 221-226
M. J. Ahmed, C. D. Stalikas, P. G. Veltsistas, S. M. Tzouwara-Karayanni and M. I. Karayannis

Abstract: A sample (100 µL) was injected into a carrier stream of 2 M H2SO4 at a flow rate of 0.1 ml/min and mixed with a reagent stream of 0.2 mM 2-(α-pyridyl)thioquinaldinamide in propan-2-ol at a flow rate of 0.3 ml/min. The fluorescence intensity due to Se(IV) was measured at 500 nm (excitation at 350 nm). A second portion (100 µL) was then injected into the carrier stream and passed through a coil (40 cm x 0.8 mm i.d.) where it was irradiated at 254 nm. The irradiated sample stream was then mixed with the reagent stream and the fluorescence intensity due to total Se was measured. Se(VI) was determined from the difference in the two fluorescence intensity values. The calibration graphs were linear from 0.01-2.2 and 0.1-2.4 µg/ml Se(IV) and Se(VI), respectively; corresponding detection limits were 1 and 10 ng/ml. RSD were 0.1-2% (n=5). The throughput was 25 samples/h. The method was applied to the analysis of alloys, hair, tap and lake water, sediments, soil, tea, flour and eggs. A simple, sensitive, highly selective, automatic spectrofluorimetric method for the simultaneous determination of selenium (IV) and (VI) as selenite-selenate by flow injection analysis (FIA) has been developed. The method is based on the selective oxidation of the non-fluorescent reagent 2-(α-pyridyl)thioquinaldinamide (PTQA) in acidic solution (1.5-3.0 M H2SO4) by Se(IV) to give an intensely fluorescent oxidation product (lambda ex =350 nm; lambda em = 500 nm). Selenium (VI) is reduced online to Se(IV), in a reduction coil installed in a photo- reactor, which is then treated with PTQA and the fluorescene due to the sum of Se(IV) and Se(VI) is measured; Se(Vi) is determined from the difference in fluorescence values. Various analytical parameters, such as effect of acidity, flow rate, sample size, dispersion coefficient, temperature, reagent concentration and interfering species were studied. The photo-reduction conditions were optimized, with an FIA procedure, for Se(VI) on the basis of its reduction efficiency. The calibration graphs were rectilinear for 0.1-2.4 µg mL-1 of Se(VI) and 10 ng mL-1 - 2.2 µg mL-1 of Se(IV), respectively. The method was applied to the determination of Se in several Standard Reference Materials (alloy, sediments and tea), as well as in some environmental waters (tap and surface water), food samples (flour and egg), a biological sample (human hair), soil sample and in synthetic mixtures. Up to 25 samples per hour can be analyzed with an RSD approximately 0.1-2%.
Selenium(IV) Selenium(VI) Fluorescence Speciation Photochemistry Selectivity Reference material Interferences

"Simultaneous Determination Of Aluminum And Iron By Flow Injection Stopped-flow Spectrophotometry"
Fenxi Huaxue 1997 Volume 25, Issue 1 Pages 37-40
Zhang, A.M.;Wang, S.H.;Wang, H.S.;Cui, H.

Abstract: Sample was injected into the FIA system over 8 s and flowed at 2.5 ml/min into a carrier stream of 10 mL 0.2 M potassium hydrogen phthalate buffer of pH 5 to merge with a reagent stream containing aqueous 0.036% cetylpyridinium bromide at 2 ml/min. The mixture then flowed through a reaction coil (30 cm long) where it was reacted with 120 µL 0.008% Chrome Azurol S in a reactor (40 cm long). After stopping the flow for 20 s, the absorbance was measured at 620 nm. Al and Fe concentrations were calculated from linear calibration graphs ranging from 0-0.4 and 0-0.8 mg/l, respectively. Only Ni(II) and fluoride interfered. The method was applied to the simultaneous determination of Al(III) and Fe(III) in tap water, tea leaves and flour, with recoveries of 93.1-109% and RSD of 1-3.1%. The sampling frequency was 90 runs/h.
Iron Aluminum Spectrophotometry Stopped-flow Simultaneous analysis Interferences

"Flow Injection Analysis. A New Technique In Analytical Chemistry"
FMBRA Bull. 1985 Volume 5, Issue NA Pages 210-NA
Osborne, B.G.;Barrett, G.M.

Abstract: NA
Bromate Iron Spectrophotometry Tecator

"Rapid Determination Of Calcium, Magnesium, Iron And Zinc In Flours Using Flow Injection Flame Atomic Absorption Spectrometry For Slurry Atomization"
Food Chem. 1993 Volume 46, Issue 3 Pages 307-311
P. Viñas, N. Campillo, I. López García and M. Hernández Córdoba*

Abstract: A procedure is described for the rapid determination of calcium, magnesium, iron and zine in flours obtained from several grains and legumes (wheat, whole meal, maize, barley, rice, rye, vetch, soy bean and field bean) using flame atomic absorption spectrometry. Suspensions up to 3% m/V from the ground samples are directly introduced into the spectrometer using a simple flow injection manifold. Calibration is performed using aqueous standard solutions of the determinands. The results obtained with this procedure agree with those obtained by conventional dry-ashing followed by dissolution in acids. Results for two standard reference materials are also given.
Calcium Magnesium Iron Zinc Spectrophotometry Slurry

"Rapid Determination Of Amylose In Milled-rice And Flour Using Flow Injection Analysis"
Nogyo Oyobi Engei 1990 Volume 65, Issue 12 Pages 1373-1379
Nakajima, Hideharu (SFS)

Abstract: A flow-injection automated analyzer, with 0.1 N KOH and I as reagents, was used to determine amylose in rice and wheat flour. The powered sample (20 mg) was mixed with 2 mL 0.1N KOH and kept at room temperature (20-25°C). After precipitation overnight, the insoluble starch settled as a ppt. and the soluble amylose remained in solution The amylose solution (supernatant) was flow-injected into the automated analyzer and amylose reacted at pH 4.5-4.7 with I to form a purple-green complex, which was determined by spectrophotometry at 620 nm. Rice and wheat flour contained ~15.1-17.7% and ~24.2-26.9% amylose, respectively. (SFS)