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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Rice Flour

Classification: Agricultural -> grain -> rice -> flour

Citations 10

"Determination Of Cadmium In Foodstuffs And Plant Materials By Flow Injection Spectrophotometry Including Ion Exchange"
Anal. Chim. Acta 1995 Volume 306, Issue 2-3 Pages 343-349
JoséA. Gomes Neto, H. Bergamin Filho, Raquel P. Sartini and Elias Ayres G. Zagatto*

Abstract: Dried powdered food or plant material (1 g) was digested with 10 mL of HNO3 for 30 min at 50°C; 2 mL of 30% H2O2 was added and the mixture evaporated to near dryness at 110°C. The residue was dissolved in 10 mL of 0.1 M HNO3 and diluted to 25 mL with water for FIA. The sample stream (3.8 ml/min) merged with an acidic NaCl stream (1.2 ml/min) then the flow passed through a strongly basic AG1 X-8 BioRad column (1 cm x 5 mm i.d.) and the Cd chlorocomplexes were retained. The flow-through the column was reversed and the analyte was eluted with 2 M NaNO3/0.1 M HNO3 (2.9 ml/min). The flow was merged with 75 µg Cd in 0.25 M ammonium acetate solution (1.2 ml/min) and then a second reagent stream which had been formed by merging 0.5 mM Malachite green and 2 M KI in 0.5% ascorbic acid (both at 0.5 ml/min); detection was at 690 nm. The detection limit was 0.11 µg/l Cd; RSD for sample digests containing 19.7 and 5.12 µg/l Cd were 2.26% and 2.72%, respectively (n = 12). The method was validated by analyzing standard reference materials (rice flour, pig kidney, dried copepoda) containing 0.75-2.71 µg/g Cd (results given). A second anion-exchange column was added to the FIA system to enable the analysis of samples which had been mineralized with HNO3/perchloric acid.
Cadmium Ion exchange Spectrophotometry Biorad Reference material

"Determination Of Cadmium In Biological Materials By Flame Atomic Absorption Spectrometry With Flow Injection Online Sorption Preconcentration"
Talanta 1994 Volume 41, Issue 12 Pages 2165-2172
Zhaolun Fang*, Shukun Xu, Liping Dong and Wenqing Li,

Abstract: A new on-line pre-concentration flame atomic absorption spectrometry (FAAS) system for trace element determination was developed based on sorption of soluble metal complexes on the walls of a PTFE knotted reactor using flow injection techniques. The system was applied to the determination of cadmium in biological materials. Cadmium complexed with sodium diethyldithiocarbamate was sorbed on the inner walls of the reactor and eluted on-line by isobutyl methyl ketone. The retention efficiency was 81% at a sampling loading rate of 5.2 ml/min. The enhancement factor was 66 and the concentration efficiency was 61/min with a 50 sec pre-concentration period, consuming 4.2 mL sample. A detection limit of 0.1 µg/l. Cd (3s) was obtained with a sampling frequency of 55/hr. The precisions were 1.2% RSD for 20 µg/l. Cd (N = 11). Thiourea and ascorbic acid/phenanthroline were used to overcome interferences from copper and iron, respectively. The analytical results obtained for powdered rice and human hair standard reference materials were in good agreement with the certified values.
Cadmium Spectrophotometry Preconcentration

"Automation In Element Preconcentration With Chelating Ion Exchangers"
J. Anal. At. Spectrom. 1987 Volume 2, Issue 6 Pages 611-614
Günter Knapp, Kurt Müller, Martin Strunz and Wolfhard Wegscheider

Abstract: A microprocessor controlled pre-concentration system that permits the automated off-line pre-concentration of several samples at the same time is described. Trace elements pre-concentrated from sample volumes of up to several hundred millilitres can be eluted by 5 mL of 2 M nitric acid. It is therefore possible to achieve pre-concentration factors of up to 100. In contrast to FIA methods all ICP-AE spectrometers can be used for the measurements. Four different chelating ion-exchange materials, Chelex 100, oxine cellulose, CPPI resin and Hyphan cellulose, were compared. Trace elements were enriched from concentrated salt solutions and from NBS standard reference materials following decomposition in the High Pressure Asher. After elution the elements were measured by ICP-AES (Plasma II) and by graphite furnace AAS (HGA-500/Zeeman 5000). Under the conditions tested, Chelex 100, the oxine cellulose and the CPPI resin can be employed satisfactorily in the automated pre-concentration of a number of elements.
Cadmium Copper Lead Manganese Nickel Zinc Ion exchange Spectrophotometry Spectrophotometry Chelation Computer Preconcentration

"Hydride-generation Atomic Absorption Spectrometry Coupled With Flow Injection Analysis"
Anal. Chem. 1985 Volume 57, Issue 7 Pages 1382-1385
Manabu Yamamoto, Makoto Yasuda, and Yuroku Yamamoto

Abstract: Flow injection analysis was combined with the gas-segmentation method described by Skeggs (Am. J. Clin. Pathol., 1957, 28, 311) for the determination of As, Sb, Bi, Se and Te. On synthetic samples the coefficient of variation were between 0.5 and 0.8% (n = 10) with detection limits between 0.04 and 0.3 ng. The results on NBS steel, wheat and rice flour, orchard leaves and coal fly ash were close to certified values and the differential determination of As and Sb in thermal water was possible. Tolerance limits for diverse ions are listed.
Arsenic Antimony Bismuth Selenium Tellurium Spectrophotometry Reference material Segmented flow

"Determination Of Arsenic And Selenium By Hydride Generation Atomic Absorption Spectrometry Using A Gas-liquid Separator And A Dehydration Trap"
Microchem. J. 1996 Volume 53, Issue 1 Pages 18-25
Hisatake Narasaki and Jun-Yan Cao

Abstract: Biological material (0.25 g) was allowed to stand overnight in 3 mL concentrated HNO3, 0.5 mL concentrated H2SO4 and 1 mL 60% HClO4 were added and the mixture was digested under low heat until the fumes of HClO4 subsided. The digests, including siliceous residues, were transferred to a Pt dish with water and evaporated to 2 mL. The residues were dissolved with 5 mL 46% HF, 1 mL 9 M H2SO4 was added and the solution was concentrated to 2 mL. The pH was adjusted to 3.5 with 1 M NH3 and applied to a SPE column (35 cm x 10 mm i.d.) packed with 10 cm Chelex 100 chelating ion-exchange resin and the column was washed with 2 x 10 mL water. For the analysis of As; the column effluents were diluted to 100 mL with water and a 10 mL portion was mixed with 5 mL 6 M HCl. Portions of both acid solutions were introduced into the flow injection hydride generation system (schematic shown) and mixed with a stream of 2% sodium tetrahydroborate(III) solution in a Pyrex mixing coil (16 cm x 2 mm i.d.). The hydride generated was collected in a gas-liquid separator, dehydrated in a dehydration trap and swept into an electrically heated furnace with a carrier stream of N2 (2.5 l/min) by manipulating electromagnetic relays and timers (operating details given). The atomized As and Se species were detected at 193.7 and 196 nm, respectively, by AAS. The detection limits were 0.6 and 1 ng/ml, respectively. Tolerance levels to 10 foreign ions are listed. The method was applied to the analysis of five NIST Standard Reference materials (listed). Results agreed well with certified values.
Arsenic Selenium Spectrophotometry Reference material Chelex

"High Performance Liquid Chromatographic Analysis Of Thiamine In Rice Flour With Fluorimetric Post-column Derivatization"
J. Chromatogr. A 1984 Volume 284, Issue 1 Pages 281-284
Hideaki Ohta, Toshiro Baba and Yoshihiko Suzuki, Eiji Okada

Abstract: Rice flour was hydrolyzed with takadiastase ('Official Methods of Analysis', AOAC, 13th Ed., 1980). After centrifugation at 3500 rpm for 20 min, the supernatant solution was subjected to HPLC on Nucleosil 5 C18, with an aqueous solution 0.01 M in NaH2PO4 and 0.15 M in NaClO4 (pH 2.2) as mobile phase. The eluate stream from the column was mixed with a stream of reagent solution [0.01% of K3Fe(CN)6 in aqueous 12% NaOH], both flowing at 0.6 mL min-1, and the thiochrome formed was detected fluorimetrically at 435 nm (excitation at 375 nm). Recoveries of thiamine(I) added at 2 ppm to rice flour were 92 to 96%, and the determination of I in several samples of brown and polished rice by the new method gave results in close agreement with values obtained by the full AOAC procedure.
Thiamine HPLC Fluorescence Method comparison Post-column derivatization

"Separation And Determination Of Copper And Zinc By Ion Chromatography Using 2-(2-benzoxazolylazo)-1-naphthol As A Post-column Derivatization Reagent"
Bunseki Kagaku 1998 Volume 47, Issue 11 Pages 861-866
Shin-ichiro Okawa, Kazuhiko Yamazaki and Tosimi Ishikawa

Abstract: An ion chromatography method using post-column derivatization with 2-(2-benzoxazolylazo)-1-naphthol(α-BOAN) in a nonionic surfactant solution of Brij35 was established for the separation and determination of Cu(II) and Zn(II). The optimum conditions for determining the elements were: an eluent containing 0.25 mol L-1 lactic acid (pH 3.1) at a flow rate of 1 mL min-1; for post-column derivatization, 2 x 10^-4 mol L-1 α-BOAN solution containing 4%(v/v) dioxane, 4%(w/v) Brij35 and sodium tetraborate at a flow rate of 0.3 mL min-1; pH at the drain of 3.3 ± 0.1; analytical column, a Shim-pack IC-C1 (5.0 mm i.d x 150 mm); oven temperature of 40°C; an injection volume of 0.02 mL; and detection at 565 nm. A linear relationship was observed between the peak hight and the amt. of elements within ranges of 80-240 and 400-2000 ppb for Cu and Zn, respectively. The relative standard deviations for the measurements (n = 7) of 120 ppb Cu and 800 ppb Zn were 2.2 and 2.0%, respectively. The detection limits of 16 ppb Cu and 195 ppb Zn (S/N = 3) were obtained. The present method was applied to the separation and determination of Cu(II) and Zn(II) in the Rice Flour (NIST SRM1568a) and Bovine Liver (NIST SRM1577b) with satisfactory results. Cu(II) and Zn(II) in rice from Australia, Thailand, China, and the U.S.A. are also determined by this method.
Copper Zinc HPIC Spectrophotometry Post-column derivatization Reference material Method comparison Optimization

"A Stopped-flow Injection Catalytic-spectrophotometric Method For The Determination Of Trace Vanadium"
Fenxi Huaxue 1996 Volume 24, Issue 7 Pages 832-834
Wang, S.H.;Zhang, A.M.;Du, L.Y.;Ma, C.L.;Liu, D.J.

Abstract: An aqueous 0.0025% malachite green solution in 0.01 M acetic acid was injected into a carrier stream of 0.01 M acetic acid (3 ml/min) and mixed in a reaction coil (25 cm long). The mixed reagent stream was merged with a sample stream containing 1 mM KBrO3 and 0.05 M tartaric acid flowing at the same rate in a second reactor (35 cm long) and the absorbance of the colored products formed was measured at 625 nm. When the absorption reached the maximum, the flow was stopped; the curve of the absorbance change was plotted for calculation of the V content. The calibration graph was linear from 20-200 µg/l of V(V). Common foreign species including 100-fold Fe(III), Co(II), nitrite and Mn(II) did not interfere. The method was applied to the analysis of foods, such as peanut, rice and wheat flour, with RSD of 2.6-3.3%. Results agreed closely with those published Wang et al. (Fenxi Shiyanshi, 1995, 14, 70).
Vanadium Spectrophotometry Interferences Stopped-flow

"Continuous-flow Vapor Generation For Inductively Coupled Argon Plasma Spectrometric Analysis. 2. Arsenic"
J. AOAC Int. 1991 Volume 74, Issue 3 Pages 516-521
Tracy ML, Littlefield ES, Moller G.

Abstract: Biological tissue, blood or water, is wet ashed in a 10 mL test tube on a programmed heating block with HNO3, H2SO4 and HClO4 at up to 310°C (details given). The cooled digest is treated with HCl and KI and the As present is reduced by NaBH4 to arsine in a simplified continuous-flow manifold. A standard pneumatic nebulizer effects the gas - liquid separation of AsH3 which is quantified by ICP-AES at 193.756 nm. The detection limit was 0.4 to 0.6 µg L-1 of As. Mean coefficient of variation were 1.2% for analysis of water samples (n = 27) and 2% for analysis of liver samples (n = 12). Recoveries ranged from 99 to 104% for tap water, bovine liver and rice flour.
Arsenic Spectrophotometry Heated reaction Nebulizer Phase separator Reference material Volatile generation

"Simple Determination Of Thiamine In Rice By High Performance Liquid Chromatography With Post-column Derivatization"
J. Liq. Chromatogr. Relat. Technol. 1993 Volume 16, Issue 12 Pages 2617-2629
Hideaki Ohta; Mari Maeda; Yoichi Nogata; Koh-Ichi Yoza; Yuko Takeda; Yutaka Osajima

Abstract: We report a rapid high-performance liquid chromatographic method for the determination of thiamine in rice with fluorimetric post-column derivatization. The analysis system consisted of a combination of both thiamine extraction with a mixture of 0.1 M hydrochloric acid-40% methanol (0.1 M HCI-40% MeOH) solution from rice flour, and chromatographic separation and determination. To extract thiamine, the rice flour was refluxed for 30 min at 60°C with 0.1 M HCl-40% HCI. The separation systems constituted of a Sorbax TMS column, column oven (55°C), elution system containing a mixture of 0.01 M sodium dihydrogen phosphate and 0.5 M sodium perchlorate solution, a mixing coil for chemical reaction and a spectrofluorimetric detector. The thiamine derivative compound was detected at 375 nm for excitation and 435 nm for emission. The recovery of thiamine was 94 -101%. The contents of thiamine in rice of six cultivars produced in Japan were determined by the above-mentioned HPLC method and AOAC method. The two methods gave comparable results and a high correlation coefficient (r = 0.958) was obtained.
Thiamine HPLC Fluorescence Post-column derivatization