Ppm Iron Research Articles

In vitro bioavailability of iron from spinach (Spinacea oleracea) cultivated in soil fortified with graded levels of iron and zinc

A pot-culture experiment was conducted to assess the bioavailability of iron from spinach cultivated in soil fortified with graded levels of iron and zinc (FeSO4 x 7H2(0) and ZnSO4 x 7H2(0), respectively). Applications of varying levels of iron to soil increased the total iron and phosphorus contents and decreased the zinc content (P < 0.05). The effect of applying varying levels of zinc was the opposite of on the minerals in spinach. The ascorbic acid content was remarkably reduced with varying levels of iron and zinc. Higher levels of zinc and lower levels of iron in the soil increased the bioavailability of iron from spinach (P < 0.05). In conclusion, the interactions of 15 ppm zinc with 30 ppm iron significantly enhanced the bioavailability of iron, total iron and zinc contents.

Further studies on Ag/BPSCCO tapes using low purity materials

Transmission electron microscopic (TEM) studies are reported on Ag-clad Bi1.7 Pb0.4Sr1.8Ca2Cu3.5O x tapes prepared by using low purity (98–99%) commercial grade materials. The self-fieldJ c values of these tapes viz. 6.14 × 103 A.cm−2 at 77 K and 1.4 × 105 A.cm−2 at 4.2 K, reported in an earlier publication, were significantly higher than the correspondingJ c values in tapes prepared with high purity (99.99%) materials. The TEM pictures on the low purity core material of the tapes reveal the presence of stacking faults and the intergrowth of the 2212 and 2223 phases which could be acting as flux pinning sites and responsible for enhancedJ c values. These defects can perhaps be traced back to the presence of 60 ppm iron in the low purity CuO as revealed by atomic absorption analysis reported earlier.

Gold and silver extraction from Hellyer lead-zinc flotation middlings using pressure oxidation and thiourea leaching

A new route for the extraction of gold and silver from three different galena-sphalerite-pyrite flotation middlings (bulk scavenger tailing, zinc middling and pyrite middling) assaying 2.3, 2.6 and 1.5 g/t Au and 82, 53 and 27 g/t Ag, respectively, and containing different proportions of the sulphide minerals was investigated. Each sample was pressure oxidised for 4 h at 200°C or 220°C and 700 kPa oxygen overpressure, at an initial acidity of either 0 or 36.8 g/l H 2SO 4. This resulted in solid products containing, respectively, either hematite and lead jarosite, or iron hydroxy sulphates and lead sulphate. Most of the zinc and copper, together with some iron and a little silver, were dissolved and were removed by filtration. X-ray diffraction (XRD) examination of the solid products from pressure oxidation at high initial acidity confirmed that they contained mainly a basic iron sulphate (Fe(OH)SO 4) with some hydrated iron sulphate (Fe 2S 2O 9·5H 2O) and lead sulphate. Thiourea leaching of these products for 4 h at natural pH (2.3–3.4) and Eh (200–350 mV vs SCE), with a thiourea addition rate of 2 g/l h −1, extracted 83–92% of the gold and 39–96% of the silver, depending upon the sample. The lowest silver extractions were from the pyrite middling. The low silver extractions could have resulted from jarosite formation during thiourea leaching. Some of the hydrated iron sulphate reacted during the leach and there was evidence of silver re-precipitation after 3 h. Thiourea consumptions were 34–73 kg/t. XRD examination of the solid products from pressure oxidation at low initial acidity confirmed that they contained mainly hematite and lead jarosite. Thiourea leaching of these products for 4 h at pH 1.5, with an addition of 17,500 ppm iron(II), an Eh of 225–250 mV, maintained with hydrogen peroxide, and a thiourea addition rate of 2 g/l h −1, extracted 46–88% of the gold but only 2–7% of the silver. The low gold extraction was obtained from the pyrite middling. The low silver extractions are believed to result from silver incorporation into the jarosite lattice during pressure oxidation. Thiourea consumptions were 16–70 kg/t. Gold and silver extractions by thiourea leaching were, in general, inferior to those obtained by cyanidation of similar pressure oxidation products after lime treatment. For cyanidation, gold extractions from all samples were generally around 90%, as was silver extraction from the basic iron sulphate/lead sulphate product. Silver extractions of 25–73% were obtained from the hematite/jarosite products, values significantly higher than those achieved by thiourea leaching. Total lime consumptions for pH adjustment after pressure oxidation and for cyanidation were up to 480 kg/t CaO for the basic iron sulphate/lead sulphate product and 52 kg/t CaO for the hematite/jarosite product. Cyanide consumptions were up to 5 kg/t NaCN.

Longitudinal changes of trace elements in human milk during the first 5 months of lactation

Human milk samples were obtained from 6 women at various times during lactation for a total of 81 samples. Those from each woman were from 10 to 18 samples, sufficient to calcuate exponential regressions on an individual basis. Trace elements were measured using Inductively Coupled Argon Plasma Spectroscopy (ICAPS). Those elements in measurable quantities were zinc, silicon, copper, iron, barium, and strontium in the order found from the highest to the lowest concentrations. Means of 6 women ranged from 3.434 to 1.146 parts per million (ppm) for zinc, from 1.121 to .0570 ppm for silicon, .3800 to .1123 ppm for copper, from .3410 to .1733 ppm for iron, from .2833 to .0057 ppm for barium, and from .1057 to .0290 for strontium. Regressions for each element longitudinally on a daily basis showed concentrations of zinc, copper and iron being reduced significantly. In the cases of silicon, barium and strontium, longitudinal changes were not significant on a statistical basis. Fractional loss of zinc per day was −.01390; for copper it was −.00836; and the fractional loss of iron on a daily basis was −.01000. Other elements detected in some, but not all, samples included aluminum, lithium, manganese, and titanium. Manganese was measurable at the minimum detection limit of .007 ppm in only 6 of 81 milk samples. The mean for the 6 samples was .016 ppm.

Regulation of the Periplasmic [Fe] Hydrogenase by Ferrous Iron in Desulfovibrio vulgaris (Hildenborough)

The periplasmic [Fe] hydrogenase from the sulfate-reducing bacterium Desulfovibrio vulgaris (Hildenborough) DSM 8303 was found to be regulated by ferrous iron availability. During growth with 5 ppm of iron, the enzyme derepressed and the specific activity increased approximately fourfold, whereas the presence of 100 ppm of ferrous iron repressed the enzyme. The repression-derepression phenomenon with ferrous iron was found to be operative when the cells were cultured under either hydrogen or nitrogen gas. This is the first reported case showing that the hydrogenase enzyme is regulated by iron, and the implications of this finding relative to the corrosion industry are discussed.

Application of ternary complexes in pharmaceutical analysis

The formation of a ternary complex of iron(III) with isoniazid-2-hydroxybenzaldehyde hydrazone(INSH) in a cetyltrimethylammonium bromide(CTAB) micellar medium, leads to a simple, sensitive and accurate spectrophotometric microdetermination of the iron(III), either in pure aqueous solutions or, particularly, in various anti-anaemic formulations. The apparent molar absorptivity of this complex and Sandell's sensitivity at 386 nm were 2.08×104 lmol−1 cm−1 and 2.68 ngcm−2, respectively. The calibration graph which was traced according to the regression line equation, A=3.70×10−1 C+1.09×10−3 (r=1.0000; n=28), was rectilinear for 100 ppb to 3.0 ppm of iron(III). The accuracy and the precision of the method could be considered as very satisfactory, since the mean CV% was 0.202 in the range 0.5–3.0 μg of iron(III) per ml. The results obtained for iron(III) by the new method and by the o-phenanthroline method, were compared statistically by means of the Student t-test and the variance ratio F-test; no significant difference was found.

Effect of dietary iron supplementation on the body burden of iron in mice

Weanling male CD-1 mice were fed 120 (control), 250, 500 and 800 ppm iron (Fe) in diets or 120 ppm Fe and injected subcutaneously (s.c) weekly with 0.5 mg Fe as iron sorbital for 7 weeks. Body weight gain, hematocrit and water consumption were not altered by iron exposure ( p=0.598, p=0.266, p=0.664 respectively). Dietary iron concentrations above 120 ppm or injection of 0.5 mg Fe s.c weekly increased liver iron stores in the mice ( p=0.0001) in a dose and time-dependent manner. Mice fed control diet (120 ppm Fe) maintained a constant concentration of iron in the liver and serum indicating that body iron level is normally maintained within narrow physiological limit. Significant positive correlations were observed between concentrations of iron in the liver and dietary levels of iron r=0.998, p=0.0001). In contrast, dietary iron concentrations correlated poorly with serum iron concentrations (r=0.024). Serum iron concentrations increased during the first 3 weeks of growth ( p<0.05) in all groups after which it was maintained at a constant level in control group but decreased in 800 ppm Fe and injected groups ( p<0.0001). The positive relationship between dietary concentration of iron and storage of iron in the liver demonstrated in this study indicates that the determination of dietary iron level may be a simple method to monitor the risk of chronic iron overload under circumstances of constant iron exposure and bioavailability comparable to ferrous sulphate. The long term intake of foods fortified with iron may lead to a significant increase in iron body stores with potential associated disease problems.

Studies on the application of photochemical reactions in a flow injection system. Part 2. Simultaneous determination of iron(II) and iron(III) based on the photoreduction of the iron(III)–phenanthroline complex

An automated procedure for the simultaneous determination of iron(II) and iron(III) was developed, involving the use of a laboratory-built flow-through photochemical reactor in a flow injection system based on the photoreduction of the iron(III)–1,10-phenanthroline complex. Optimum analytical conditions were established. A 100 mm3 sample injection gave linear working ranges of 0.1–120 ppm of iron(II) and 0.2–120 ppm of total iron. The sample throughput was 40–60 h–1. The proposed method was applied to the determination of iron(II) and iron(III) in synthetic mixtures of standard iron(II) and iron(III) and the catalyst for synthetic ammonia manufacture.

The effect of dry heat on the bioavailability of iron in soy flour

Bioavailability of iron in soy flour was investigated by the Hemoglobin Regeneration Efficiency (HRE) procedure in 50 three‐month‐old Sprague‐Dawley rats. Rats weighing 250 ±7 g and with a mean hemoglobin level of 12.9 g/dl were randomly assigned to one of five treatment groups: baseline (BL), unheated soy flour (UH), soy flour heated at 225°F for either 10 min (H10), 30 min (H30), or 120 min (H120). The animals were fed diets (46 ppm iron) containing the soy flour for 21 days. HREs of UH, H10, H30, H120 diets were 17.6, 16.8, 17.7 and 16.8%, respectively. Apparent iron absorption from the UH, H10, H30 and H120 diets was 94.7, 94.3, 93.9 and 94.3%, respectively. Serum iron was significantly lower (p&lt;.001) and total iron binding capacity was significantly higher (p&lt;.001) in rats fed the H120 diet. Iron concentrations in the liver, spleen, heart and kidney were significantly lower in rats fed H30 or H120 diets. These results suggest that prolonged heating of soy flour may reduce iron bioavailability and result in depletion of iron stores.

Determination of iron absorption by rat bioassay. Evaluation of methods of dosing59Fe on radioiron absorption from plant diets

We studied the potential of an animal model to predict nonheme iron absorption in humans and tested a feasible and easy technique of dosing 59Fe to evaluate bioavailability of dietary nonheme iron. Plant diets containing about 20 ppm or 75 ppm iron were the nonheme iron sources with ferrous sulfate (75 ppm) as a reference. Radioiron was administered by (a) gavaging in water, 1 h after a meal; (b) mixing with the meal; and (c) making a slurry with the meal and gavaging. No significant differences were found (P less than or equal to 0.05) in 59Fe absorption among the three methods of administering radioiron. Absorption of 59Fe was similar to apparent iron absorption for all diets tested, whether the animals consumed the same diet as that of the test meal or a different diet. A high correlation (r = 0.88) obtained between the apparent iron absorption and 59Fe iron absorption for different dosing techniques, indicates that extrinsic iron tag administered by any of these methods is valid to measure nonheme iron absorption. Apparent iron absorption values determined by rats fed 20 ppm or 75 ppm dietary iron from plant sources were similar to reported values for humans. It is concluded that the normal adult rat is an appropriate model to study iron bioavailability of human foods when iron status, maturity, iron intake relative to requirement, and method of measurement are similar to the human situation.

The effect of various dietary zinc concentrations on the biological interactions of zinc, copper, and iron in rats

Three groups (14 rats each) were fed one of the following diets for 8 wks: a control purified basal diet containing 12 ppm zinc, 5 ppm copper, and 35 ppm iron; the basal diet with less than 2 ppm zinc; or the basal diet supplemented with 1000 ppm zinc. Rats fed the zinc-deficient diet had decreased weight gain, moderate polydipsia, and intermittent mild diarrhea. The zinc-supplemented rats had a cyclical pattern of food intake and weight loss from weeks 5 to 8. Tissue concentrations suggest that zinc and copper were not mutually antagonistic with chronic dietary imbalances. If tissue element concentrations reflected intestinal uptake, then competition and/or inhibition of intestinal uptake occurred between zinc and iron. The fluctuations in tissue element concentrations that occurred with increased duration of the study were at variance with previous studies of shorter time periods. The dietary proportions of zinc, copper, and iron appear to influence zinc, copper, and iron metabolism at the intestinal and cellular transport levels over a given period of time.

Determination of iron, cobalt and nickel as chelates with 4-(2-thiazolylazo)resorcinol by reversed-phase high-performance liquid chromatography

The chelates of iron, cobalt and nickel with 4-(2-thiazolylazo)resorcinol were separated on a column (250 × 4.6 mm i.d.) of Zorbax ODS (6 µm) with a mobile phase (0.75 ml min–1) of methanol–water (40 + 60, v/v) containing 0.01 mol dm–3 KH2PO4—Na2HPO4 buffer (pH 7.0) and were detected at 580 nm. The calibration graphs were rectilinear from 0.1 to 5 ppm for both cobalt and nickel, and from 1 to 5 ppm for iron. The detection limits were 2.0, 0.2 and 0.6 ng for iron, cobalt and nickel, respectively. The method has been applied to the analysis of real samples.

Infection of Shell Eggs With Yersinia Enterocolitica

Shell eggs were immersed in bacterial suspensions containing 106Yersinia enterocolitica/ml and subjected to either a temperature differential or a pressure differential inoculation technique in the presence or absence of 20 ppm iron to determine if Y. enterocolitica could penetrate and infect shell eggs. No Y. enterocolitica was detected inside eggs immediately after inoculation. After 3 d of storage at 10°C, Y. enterocolitica was detected in only one egg out of 24. After 7 d of storage at 10°C, approximately 14% of eggs from bacterial suspensions with no iron supplementation contained Y. enterocolitica. After 14 d, Yersinia counts exceeded log 6.0 CFU/ml and Yersinia were found inside 100% of eggs examined.

Magnetic Characterization of 4,4′-(Butadiyne-1,4-Diyl)-Bis-(2,2,6,6-Tetramethyl-4-Hydroxy-Piperidin-1-Oxyl) and its Products on Thermal Treatment

Abstract The magnetic properties of the title compound have been measured with a superconducting squid susceptometer before and after thermal treatment. The ferromagnetism that has been previously reported by other authors to occur in the title compound following thermal treatment has not been observed. This material (α-phase) and a similar polymorph (β-phase) are shown to exhibit normal (Curie-Weiss) behavior before and after heat treatment and have a maximum ferromagnetic contribution corresponding to 5 ppm iron contamination.

Iron Fortified Hydroponically-Grown Barley-Sprout Flour

In an attempt to increase the iron content of barley flour, seeds were soaked in distilled water for 6h, and grown hydroponically under controlled conditions in the dark for 132h. They were sprayed automatically every 4h for 15min with either distilled water or distilled water to which iron as ferrous sulfate had been added at 5, 7 and 10 ppm iron concentrations. The sprouts were frozen, freeze-dried, ground into flour and analyzed for iron.Iron bioavailability from the barley seed flour, sprouted barley flour (grown in 5 ppm iron solution) and ferrous sulfate was evaluated by the efficiency of converting dietary iron to hemoglobin. Rats made anemic by an iron-deficient diet for 4 weeks were switched to one of three repletion diets containing 21mg of iron per kg diet for two weeks.Increasing the concentration of iron in the spray water resulted in marked increases in the sprout iron levels, but solutions of 7 ppm and above inhibited seed germination. The values for efficiency of iron utilization from ferrous sulfate, barley seed and the germinated barley diets were 64, 41 and 51 percent, respectively. Iron from the sprouted barley flour diet therefore, was significantly more available than that from the diet containing ungerminated barley seed flour.

Spectrophotometric determination of iron as phenylfluorone complex sensitized with Triton X-100

The effect of some surfactants and protective colloids on the absorbance of the iron(III)-phenylfluorone complex has been investigated. The binary complex formed at pH 9.0 show a molar absorptivity of 7.5×104 l · mol−1 · cm−1 at 530 nm. In the presence of 2% Triton X-100, at the same pH, the molar absorptivity of the sensitized complex was 1.19×105 l · mo−1 · cm−1 at 555 nm. Full colour development of the sensitized complex occurred within 25 min and Beer's law was followed up to 0.53 ppm of iron. The molar ratio and continuous variation methods indicated a 1∶3 metal-ligand ratio for the sensitized complex. The effect of various amounts of different ions has been studied under the experimental conditions and some masking agents were recommended. The method has been applied to the determination of iron in copper and nickel metals and some non-ferrous alloys.

Spectrophotometric Determination of Iron In Wines, Vegetables, Pharmaceutical Compounds and Minerals With Mandelohydroxamic Acid (Mha)

Abstract A new reagent, mandelohydroxamic acid (MHA), which has an easy synthesis and an high water solubility (64.48 gL−1) is proposed for a simple, rapid, selective and sensitive method for the spectrophotometric determination of iron based upon the formation of the MHA-Fe(III) complex and its extraction into n-butanol under optimum operating conditions. A yellow color is formed when the complex is extracted from acidic aqueous medium (Vw/Vo[dbnd]5) in the organic solvent (apparent molar absortivity 1.15 104 L mol−1 cm−1 at a wavenlength of 430 nm). the relative error is 0.5% (2 ppm of iron) and the detection limit is 0.05 g mL−1 of Fe(III). the method has been applied to the determination of iron in wines, vegetables, pharmaceutical compounds and minerals.

Body and egg iron content in shaver and new hampshire chickens

1. 1. A comparative study on the iron content in internal organs (blood, liver, spleen, kidneys and heart), carcass and feathers, as well as on the whole iron content has been carried out at different ages (4, 8, 13, 18 and 24 weeks), on two chicken breeds (shaver and New Hampshire). 2. 2. The iron content in internal organs in shaver was higher than in New Hampshire. 3. 3. A tendency of the iron content in the carcass to decrease with age has been observed for both breeds; values were higher for laying shaver hens. 4. 4. The egg-producing strain, shaver, showed a greater iron status with a stable body iron content from 13 weeks on (53–55 ppm), permitting a constant laying frequency (90%) during an 18-month period, with only a small reduction of egg iron content from 33.8 to 31 ppm. 5. 5. The whole body iron decreased progressively with age in the New Hampshire broiler strain to 42–49 ppm iron, and the laying process sharpened this tendency. A drastic reduction in laying, accompanied by a lower egg iron content (28.9 ppm iron), was observed. 6. 6. Iron data obtained in the present paper reflect the specific genetic adaptation to egg production of the shaver strain.

Quantum diffusion of positive muons in copper.

The diffusion of positive muons (${\ensuremath{\mu}}^{+}$\ensuremath{\approxeq}0.11\ifmmode\times\else\texttimes\fi{}proton mass) in copper was studied experimentally by the zero-field muon-spin-relaxation method in a temperature (T) range from 70 mK to 190 K, using a pulsed muon beam suitable for the present method. The measurements were performed in three copper samples of different purities to see the effect of impurities on the nature of the ${\ensuremath{\mu}}^{+}$ diffusion. We find that the diffusion (hopping) rate \ensuremath{\nu} in ultrapure copper decreases rapidly with decreasing temperature, reaches a minimum at T=30--70 K, then begins to increase. The T dependence in the low-temperature region follows ${T}^{\mathrm{\ensuremath{-}}\ensuremath{\alpha}}$(\ensuremath{\alpha}\ensuremath{\simeq}0.67\ifmmode\pm\else\textpm\fi{}0.03) at 0.5--10 K and levels off below 0.5 K. The behavior is strongly modified by impurity consisting of \ensuremath{\approxeq}100 ppm iron below 10 K. The T dependence in the pure copper is accounted for by new theories developed independently by Kondo and by Yamada, predicting a hopping rate \ensuremath{\nu}\ensuremath{\propto}${T}^{2K\mathrm{\ensuremath{-}}1}$(0\ensuremath{\le}K\ensuremath{\le}1/2 for a single charged particle), where the factor ${T}^{2K}$ comes from the renormalization of the muon tunneling matrix due to the nonadiabaticity of the conduction electron interacting with the moving muon. From the present results the constant K is determined to be K=0.16\ifmmode\pm\else\textpm\fi{}0.01.

An on-line ferromagnetic wear debris sensor for machinery condition monitoring and failure detection

Wear debris analysis is widely used to monitor the condition and predict the failure of oil-wetted components in machinery. Because of deficiencies in conventional methods of application, which involve periodic laboratory analysis of oil samples, interest in potential on-line methods is accelerating to satisfy demands for greater reliability assurance and maintenance economy. Thus far, concepts based on ferromagnetic particle sensing principles have shown the greatest promise. In this paper, a novel sensor capable of continuously monitoring cumulative ferromagnetic wear debris in lubricating oil scavenge lines is described. Suspended particles are alternately trapped electromagnetically and released through the inductance coil of a radio frequency oscillator, causing a frequency transient proportional to debris mass. By virtue of the pre-concentration of particulate debris, high detection sensitivity of the order of 1 ppm iron is achieved. Trapping magnet current and frequency measurement are regulated and monitored using a microprocessor-controller. Validation of the system under simulated machinery operating conditions was accomplished with an experimental oil circulation test loop to which measured amounts of particulate iron were introduced. System variables, including magnet current, oil temperature and viscosity, linear flow velocity, wear particle size and nitrogen and water entrainment, were observed to influence sensor response. For a given set of operating parameters, however, the response was directly proportional to the mass of ferromagnetic material. Results of a subsequent field evaluation trial on a test gearbox confirmed the feasibility of the sensor for practical on-line application.