Determination of Iron Species in Samples of Iron-Fortified Food (original) (raw)
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Quantitative Determination of the Elemental, Ferrous, Ferric, Soluble, and Complexed Iron in Foods
Journal of Food Science, 1979
A method for the simultaneous quantification of the vxious forms of iron added or endogenous to foods has been developed. The total, elemental, and soluble iron are determined with minimal pretreatment by atomic absorption spectrophotometry. The iron valences and complexed iron are measured spectrophotometrically us ing the bathophenanthroline reagent. The method was both reproducible and accurate in measuring iron added to plant material and to a formulated instant beverage. The procedure may be applied to determination of possible changes in the iron-fortified processed foods
Modification of the ferrozine technique to analyze iron contents in different foods
Biological Trace Element Research, 1998
A methodology for the determination of iron in foods fortified with this element or in nutritional products is important and has to be sensitive and rapid. In developing countries, an inexpensive and reliable methodology is also required. For this purpose, the Gordon's Ferrozine technique was slightly modified and assayed with yogurt, dry powdered milk, and cereal mixtures, all of them fortified with iron, using an internal standard as the reference methodology. The obtained results demonstrate a close correlation between the standard curve interpolation method and the internal standard reference method (correlation coefficient r 2 = 0.9950) in a wide range of concentrations. The slope (0.9998 _+ 0.0040) demonstrates that both procedures measure equal amounts of iron. The conclusion is that the proposed technique is a reliable, practical, and inexpensive methodology for iron determination in different foods fortified with iron.
Food Analytical Methods, 2012
The use of slurry sampling as the procedure for sample preparation provides simplicity, speed, and low consumption of reagents in analytical methods. In this paper, a method based on slurry sampling for the determination of iron in samples of fortified milk powder by high-resolution continuum source flame atomic absorption spectrometry was developed. Multivariate design techniques were applied for the optimization of experimental conditions of the method for a sample mass of 100 mg, final volume of slurry of 10 mL, and using the absorbance signal as response. Initially, a two-level full factorial design was used for the preliminary evaluation of the variables involved in slurry preparation: concentration hydrochloric acid, Triton X-100 concentration, and sonication time. Then, the Doehlert matrix was applied for the determination of the critical conditions: 2.5 mol L −1 hydrochloric acid and sonication time of 20 min. External calibration technique with aqueous standard was used for the quantification of iron. This way, the method allowed iron determination with limits of detection and quantification of 0.9 and 3.0 μg g −1 , respectively. The precision expressed as the relative standard deviation was evaluated under repeatability and reproducibility conditions, being 3.2% and 4.0%, respectively. Addition/recovery test was used for assessing the accuracy of the method, and the recovery values achieved were in the range of 90-110%. The method was applied for iron determination in eight samples of fortified milk powder, and the obtained concentrations varied from 95.4 to 295.6 μg g −1 . The results were compared with those obtained after acid digestion, and no significant difference was observed applying t test at the 95% confidence level.
Comparative study of spectroscopic techniques for the estimation of iron in apple and vegetables
Journal of Saudi Chemical Society, 2010
Iron has been determined in apple and vegetables spectrophotometrically, by complexing it with xylenol orange. 1:1 complex formed in a highly acidic medium is measured for its absorbance at its k max of 585 nm. The results have been compared by employing atomic absorption technique. Apples and vegetable samples were collected from local markets of Pakistan. Statistical manipulations, t-test and F-test, were performed and it was found that the results from the two techniques have an excellent agreement.
American Journal of Applied Sciences, 2005
The reaction of iron (II) with 2, 6-diacetylprydine dioxime (H 2 dapd) and 2-acetylprydine monoxime (Hapm) in 10% and 60% v/v ethanol-water solution at pH 2.5 and 7.5, respectively, were studied using direct and first derivative spectrophotometry. Fe (III) is reduced by H 2 dapd and gives iron (II) complex. A simple, rapid, selective and sensitive method for the determination of Fe (II), Fe (III) and a mixture of them with the H 2 dapd reagent in acid water-ethanol medium after the solution attained to stand periods of 30 sec, 4 hr and 4 hr, respectively, are proposed. Hapm also reacts with Fe (II) to form [Fe(Hapm) 3 ] 2+ complex with less selectivity and sensitivity than H 2 dapm reagent. Calibration graph with [Fe(H 2 dapd) 2 ] 2+ is linear over the range 0.28 µg mL¯1 with an apparent molar absorptivity of 8.481×10 3 L mol¯1cm¯1 at λ m 428 nm. Linear dynamic ranges are 0.01-11.0 and 0.07-11.0 µg mL¯1 iron (II) as [Fe(H 2 dapd) 2 ] 2+ complex for direct and derivative modes, respectively. The analytical sensitivity is 4.44×10-3 µg mL¯1 for direct and 9.15×10-5 µg mL¯1 for derivative spectrophotometry with [Fe(H 2 dapd) 2 ] 2+ complex. First derivative method enhances the sensitivity of the Fe(H 2 dapd) 2 ] 2+ more than direct one with two folds for Ni 2+ , Co 2+ , Cu 2+ and Cr 3+. A linear equation was derived from iron (II) determining as Fe (H 2 dapd) 2 ] 2+ in the presence of synthetic solution containing Ni 2+ , Co 2+ , Cu 2+ and Cr 3+. The use of H 2 dapd reagent for the determination of total iron spectrophotometerically in foodstuffs, herbs, spices (rocks) after wet ashing (wet digestion) in the absence of reducing agent is compared with that employing AAS.
Food Analytical Methods, 2009
A newly synthesized bis-azo dye, 2,6-bis(1hydroxy-2-naphthylazo)pyridine (PBN) was used as a sensitive reagent for iron. To determine the metal ion using a spectrophotometer in the concentration range between 0.3 and 2.76 ppm (molar absorptivity of 2.65×10 4 l mol −1 cm −1 at 550 nm). In a phosphate-buffered medium, none of the transition metals, except Fe(II), Co(II), Ni(II), Cu(II), and Hg(II), produced color with the reagent; however, colors produced by Co(II), Ni(II), Cu(II), and Hg(II) could be masked using thiosemicarbazide, therefore, making the reagent highly selective for iron determination. The reagent was applied for the estimation of iron levels in milk, food grains, and tea samples and the results were compared with the iron levels found in those samples using AAS.
Spectrophotometric Determination of Iron in some Commercial Iron Containing Tablets/Capsule
Foundation of Computer Applications, 2020
A comparative study of the determination of iron composition in some commercial iron tablets/capsule using spectrophotometric method. Spectrophotometric method is based on the formation of complex iron compound-ferrous tris-o-phenanthroline complex by boiling with hydroxylamine hydrochloride and subsequent addition with 1, 10 -phenanthroline at p H ~ 3±0.2 and the absorbance of this colored solution is measured with a spectrophotometer at 508nm. A calibration curve was found to be linear up to the concentration range of 0.0004 mg/ml to 0.0040 mg/ml. Total four pharmaceutical samples from different pharmaceutical companies were analyzed and results were compared with WHO iron intake for human consumption requirement. The study showed that the total iron content in pharmaceutical samples were 46.41 mg, 28.93 mg, 18.86 mg and 29.54 per 1g of the samples. These values are in good agreement with WHO standard and pharmaceutical range.
Food and nutrition bulletin, 2013
In a number of Southeast Asian countries and China, fish sauce and soy sauce produced at the industrial level are fortified with iron. Unfortunately, the food producers and regulatory agencies implementing fortification programs do not always have the capacity to monitor the programs on an ongoing basis. To assess a new portable device for the quantitative measurement of iron content of fortified sauces that could be used to control fortification levels. The linearity, detection limits, and inter- and intraassay variability of this device were assessed on fish sauce and soy sauce fortified with ferrous sulfate, ferrous fumarate, and sodium iron ethylenediaminetetraacetate (NaFeEDTA); the accuracy of the results was determined by comparing them with the results obtained by atomic absorption spectrophotometry. Measurements required a minimum incubation time of 1 hour for iron sulfate or iron fumarate and 24 hours for NaFeEDTA. Linearity of the results ranged from 2 to 10 mg iron/L for...
Microchimica Acta, 2003
Squaric acid (1,2-dihydroxy-3,4-diketocyclobutene) is used in a specific reaction with Fe(III) for the spectrophotometric determination of Fe(III) and total iron content. The optimization of the experimental parameters leads to the establishment of a simple, fast and accurate analytical method. The analytical procedure includes mixing ammonium squarate (40 mM), prepared in a phthalate buffer solution of pH 2.7, with the sample and measuring the absorbance at 515 nm. The molar absorptivity of the colored product is 3.95Â10 3 L Á mol À 1 Á cm À 1 , at 515 nm. Calibration graphs for Fe(III) are rectilinear for 0.5-20 mg L À 1 , with a detection limit of 0.3 mg L À 1 and r.s.d. not exceeding 2.5%, for five replicates of a 3.0 mg L À 1 standard solution. The method has been successfully applied to the determination of iron (III) and the total iron content after quantitative oxidation of iron (II). The results for several analyzed samples when compared with those acquired by using the FAAS technique, were found to be in satisfactory agreement.
Analysis of Iron Content in Food Supplements in Relation to the Safety of Their Use
Acta Poloniae Pharmaceutica - Drug Research
The objective of the study was to test dietary supplements available on the European market with regard to their iron content. Twenty-nine vitamin and mineral supplements were investigated, with additional assessment of their mass homogeneity. Iron was determined by means of the AAS 1 method following microwave mineralization of particular samples. Findings were compared to iron contents declared by producers. Tested supplements were analyzed with regard to the ratio between the amount of iron supplied to the body and the RDA 2 for adults and pregnant women, as well as in view of the number of preparation pieces required to be taken in order to ensure the RDA in the groups included in the research. All preparations were characterised by high mass homogeneity. The iron content determined in the supplements was different from the values indicated by the producers on the packages. Four supplements did not meet the European requirements concerning acceptable limits of nutrient tolerance stated on the labels. Tolerance for iron value in food supplements indicated by producers on packages varied from RDAs for the studied groups. The dosage recommended by the producer was mostly different from the dosage necessary to meet the requirements for iron RDA in the studied groups.