Presence Of Chromium Research Articles

Detection of chromium in presence of iron and manganese

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetection of chromium in presence of iron and manganeseWolfgang Werner Cite this: J. Chem. Educ. 1985, 62, 4, 349Publication Date (Print):April 1, 1985Publication History Received3 August 2009Published online1 April 1985Published inissue 1 April 1985https://doi.org/10.1021/ed062p349RIGHTS & PERMISSIONSArticle Views115Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (696 KB) Get e-Alerts Get e-Alerts

The effects of hexavalent and trivalent chromium on fertilization and development in sea urchins

The action of Cr 6+ (as chromate) and Cr 3+ (as sulfate and nitrate) on fertilization and development has been investigated in sea urchins. By rearing the embryos in the presence of chromate (5 × 10 −5 to 5 × 10 −4 m), the differentiation of the gut and skeleton was severely affected. The treatment of sperm before fertilization with CrO 2− 4 (10 to 30 min, 10 −4 to 10 −2 m) resulted in a number of abnormal larvae, depending on the length of exposure and the CrO 2− 4 concentration. Morphological and quantitative changes of mitotic activity during cleavage were observed as a result of CrO 2− 4 exposure of zygotes, as well as of sperm and egg pretreatment. The exposure of embryos to Cr 3+ after fertilization permitted larval differentiation, but affected the motility and hatchability of the embryos. The pretreatment of gametes with Cr 3+ never induced larval malformations. Cr 3+ exerted a strong depressive action on fertilization by decreasing the fertilizing capacity of sperm and leaving the fertilizability of the eggs almost unaffected.

Photokatalytische Systeme. XLVIII. Ungewöhnliche lichtinduzierte Redoxreaktionen von Cobalt(III)‐, Eisen(III)‐ und Kupfer(II)‐Komplexverbindungen in Gegenwart von Chromsäureestern

Photocatalytic Systems. XLVIII. Unusual Light‐Induced Redox Reactions of Cobalt(III), Iron(III) and Copper(II) Complexes in Presence of Chromic Acid EstersThe coordination compounds[Co(NH3)5H2O]3+,[Co(NH3)4(H2O)2]3+,[Co(en)2(H2O)Cl]2+ (en = ethylendiamine), [L2(H2O)Fe‐O‐Fe(H2O)L2]4+ (L = 1,10‐phenanthroline; 2,2′‐bipyridine) and [CuL2]2+ (L = 2,9‐dimethyl‐1,10‐phenanthroline) show no or neglegible photo redox reactions upon irradiation wave‐length above 350 nm. However, in the presence of chromate(VI), water, and different alcohols like methanol, ethanol, i‐propanol and n‐propanol a very efficient light‐induced formation of cobalt(II), iron(II) and copper(I) (ϕ = 0,7; Λirr = 375 nm) can be observed together with reduced generation of chromium(III). The participation of chromium(V) in the primary step of the photolysis of chromic acid esters was shown to be the reason for these unusual light‐induced redox reactions. The coordination compounds under discussion behave as very efficient scavengers for chromium(V) connected with simultaneous reoxidation to chromate(VI) and reduction to the appropriate cobalt(II), iron(II) and copper(I) compounds. The general importance of the participation of chromium(V) in the primary step of the photolysis of chromate(VI) in non‐aqueous solvents is also shown by investigations of the photochemical behaviour of the system metal complex/CrO4—, Cr2O7—/dimethylsulfoxide. Possible mechanisms of the light‐induced reductions of the metal complexes are discussed.

Analysis of chromates for traces of Cr(III) by solvent extraction and inductively coupled plasma atomic emission spectrometry

A method for the determination of quantities of 0.5–500 μg of Cr(III) in the presence of chromates and dichromates is described. The samples are dissolved in an aqueous solution buffered at pH 7.0; the Cr(III) is selectively chelated with 2-thenoyltrifluoroacetone and extracted into xylene. The extracted chromium is analyzed using inductively coupled plasma emission spectrometry. Extraction of 1.0 μg Cr(III) from 5.0 mg K2Cr2O7 was accomplished and easily determined in a volume of 25 ml of xylene. The relative standard deviation for the determination of Cr(III) contents ranging from 4.0 × 10−8 g/ml to 2.0 × 10−8 g/ml was ± 0.079. Using a minimum signal to noise ratio of 10∶1, the detection limits of the method were determined to be approximately 2.0 × 10−8 g/ml xylene. Chloride, high surface area silica, and easily oxidized amorphous boron give rise to only minor interferences.

A survey of respiratory symptoms and lung function in ferrochromium and ferrosilicon workers.

Lung function and the prevalence of generalized obstructive lung diseases (GOLD) were studied in three groups of electrofurnace workers in a ferrochromium and ferrosilicon-producing plant. When compared with an internal reference group forced vital capacity was reduced in all groups. Compared with an external reference group the prevalence of GOLD was increased in all three groups. It is known that traces of chromates are present in the working atmosphere at the plant. No connection between the presence of chromates and GOLD could be documented. It is suggested that the documented adverse effects are due to high levels of total dust, possibly with an additional effect due to exposure to amorphus silica dust.

Depressive action of chromate and dichromate salts on galena

The depressive action of chromate and dichromate salts on galena was investigated theoretically and experimentally. The potential-pH diagram for the system Pb-Cr-S-H2O at 25°C was constructed. It showed that lead chromate has a stable domain over a wide range. Considering the pseudostable character of chromate ions, the stable domain of lead chromate extends to reducing conditions. Thermodynamic and kinetic considerations lead to the following reactions as proposed mechanisms of depressive action of chromates or dichromates on galena:3PbS + 11 CrO4− + 16H+ =3PbCrO4 − 4Cr2O3 + 3SO4− + 8H2Oand3PbS + 5HCrO4− + 5H+ =3PbCrO4 + Cr2O3 + 3So + 5H2OThese reactions explain experimental observations such as the shift in pH of buffered solutions containing galena in the presence of chromates, the enhanced adsorption of chromates on the surface of galena in the presence of dissolved oxygen, and the reduced chromate adsorption on the galena surface above pH 9.Infrared spectroscopic analysis of the surface products on galena treated with chromate or dichromate solutions confirmed the formation of lead chromate. Although the formation of chromic oxide or chromic hydroxide was not confirmed because of insufficient sensitivity of the method used, the recent work by Matsuokaet al., supports the proposed mechanism. Résumé L'action déprimante de chromate ou de bichromate sur la galène a été étudiée de façon théorique et expérimentale. Le diagramme potentiel-pH pour Ie système Pb-Cr-S-H2O à 25°C a été établi et a montré que le chromate de plomb possède un domaine stable étendu. En considérant Ie caractère pseudostable des ions chromates, le domaine de stabilité du chromate de plomb existe jusqu'aux conditions de réductions. Des considérations thermodynamiques et cinétiques conduisent, pour les mécanismes dépressifs des chromates ou des bichromates sur la galéne, aux réactions suivantes:3PbS + 11 CrO4− + 16H+ = 3PbCrO4 − 4Cr2O3 + 3SO4− + 8H2Oet3PbS + 5HCrO4− + 5H+ = 3PbCrO4 + Cr2O3 + 3So + 5H2OCes réactions expliquent les observations expérimentales telles que le changement du pH des solutions tampons contenant de la galène en présence de chromates, l'augmentation de l'adsorption des chromates sur la surface de la galène en présence d'oxygène dissout et la diminution de cette même adsorption pour des pH supérieurs à 9.Des analyses spectroscopiques en infra-rouge des produits de surfaces de la galène traitée en présence de chroma tes ou de bichromates confirment la presence de bichromate de plomb. Cependant, la formation d'oxyde chromique ou d'hydroxyde chromique n'a pu être établie à cause des limites expérimentales de la méthode utilisée.

Acute potassium dichromate poisoning. Treated by peritoneal dialysis.

Although the industrial hazards of both acute and chronic chromate poisoning are well recognized, 1-2 the ingestion of hexavalent chromium compounds is uncommon and usually fatal. The recording of such oral poisonings in children, particularly potassium dichromate, is extremely rare. 3-7 This brief account records the first ingestion of potassium dichromate by a child treated by peritoneal dialysis. Report of a Case A 14-year-old boy was transferred to UCLA Hospital three days after the ingestion of approximately 1.5 gm of potassium dichromate obtained from his chemistry set and taken in an attempt to get high. Ingestion was followed immediately by nausea and vomiting. Gastric lavage was performed at a local emergency room, and the presence of chromate in the stomach was confirmed. The patient was admitted to the hospital and given parenteral fluids in an attempt to induce diuresis. Twenty-four hours after admission he became anuric, and his blood urea

Studies in qualitative inorganic analysis. part XXXIX

A virtually specific test for vanadium(V) is described which, in particular, permits the detection of vanadate in the presence of chromate and molybdate. The behaviour of vanadate in the anion separation scheme of the MAQA scheme of qualitative analysis has been investigated.

The transport of oxidized glutathione from the erythrocytes of various species in the presence of chromate.

1. Erythrocytes from normal and glucose 6-phosphate dehydrogenase-deficient humans were subjected to hydrogen peroxide diffusion to oxidize the GSH. Studies were carried out in the presence and absence of chromate to inhibit glutathione reductase and with or without the addition of glucose. 2. The GSH content of erythrocytes from other species was oxidized by subjecting them to hydrogen peroxide diffusion in the presence of chromate and glucose. 3. Chromate (1.3mm) inhibited glutathione reductase by about 80%, whereas glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, hexokinase, phosphofructokinase and pyruvate kinase were not inhibited. 4. The GSSG formed was transported from the erythrocytes to the medium. 5. The transport rate of GSSG from glucose 6-phosphate dehydrogenase-deficient erythrocytes subjected to hydrogen peroxide diffusion in the presence of chromate was comparable with that from normal and glucose 6-phosphate dehydrogenase-deficient erythrocytes. 6. The rate of transport of GSSG from erythrocytes of various species studied could be ranked: pigeon>rabbit>rat>donkey>man>dog>horse>sheep>chicken>fish.

Amperometric determination of chromium (III) in the presence of chromate, using ethylendiaminetetraacetic acid

1. The formation of less inert complexes of chromium (III) with acetate or bicarbonate ions substantially accelerates the complex formation of chromium with EDTA, which permits an amperometric determination of chromium in the titration of an excess of the reagent with a solution of copper salt. TABLE 2. Determination of Chromium (III) in the Pres-ence of Chromate (n=3; α=0.95). RatioCr3+/Cr (VI) Amount of Cr3+, mg. taken found taken found taken found 1:0 1,14 1,15±0,06 1,71 1,72±0,09 3,50 3,48±0,07 1:50 1,71 1,72±0,04 2,86 2,86±0,08 3,50 3,50±0,04 1:100 1,71 1,69±0,05 2,86 2,85±0,04 3,50 3,52±0,10 2. The method permits the determination of 1–3 mg chromium (III) in 10 ml of a solution with an error of less than 1%. The determination is not hindered by hundredfold amounts of chromate.

Contributions to the basic problems of complexometry—XIII : Determination of aluminium and tervalent chromium in the presence of chromate

Aluminium can be determined in the presence of tervalent chromium and chromate using 1,2-diaminocyclohexanetetra-acetic acid (DCTA), which forms a complex with aluminium even in the cold. This phenomenon enables a successive determination to be made of aluminium (iron) and tervalent chromium in the presence of hexavalent chromium. This procedure cannot be carried out with the commonly used ethylenediaminetetra-acetic acid (EDTA).

Spectrophotometric determination of chromium with 1,2-diaminocyclohexanetetraacetic acid

Chromium(III) forms a water-soluble complex with DCTA. The violet complex has maximum absorbance at 540 mμ and obeys Beer's law from 2 to 150 μg chromium per ml. The molar extinction coefficient is 245. Determinations of copper and chromium, cobalt and chromium, and nickel and chromium in presence of each other are described. The complex contains chromium and the reagent in a ratio of 1 : 1. The stability constant of the complex is 1.9·10 22.

Determination of Trivalent Chromium in Presence of Chromate

Determination of Trivalent Chromium in Presence of Chromate

Hydrogen Peroxide Determination in Presence of Chromate

Hydrogen Peroxide Determination in Presence of Chromate

Determination of Sulfate in Presence of Chromate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of Sulfate in Presence of ChromateWilliam Meldrum, William Cadbury, Jr, and Walter LucasseCite this: Ind. Eng. Chem. Anal. Ed. 1941, 13, 7, 456–457Publication Date (Print):July 1, 1941Publication History Published online1 May 2002Published inissue 1 July 1941https://doi.org/10.1021/i560095a005RIGHTS & PERMISSIONSArticle Views34Altmetric-Citations3LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (264 KB) Get e-Alerts

Inhibition of Nitrification by Chromates

THE occasional presence of chromates in sewages which receive discharges of trade effluents from the chromium-plating industry led us to investigate the influence of chromate on sewage purification processes. Samples of sewage containing sufficient potassium chromate to provide 1, 10 and 100 mgm. chromium per litre of sewage were treated in laboratory percolating filters, and comparisons were made with a control filter. The results, already published1, showed the oxidation of organic matter proceeded satisfactorily with up to 10 mgm. chromium per litre, but that nitrification of ammonium compounds did not occur to the same extent as in the control filter.

Determination of Lead as Chromate in Presence of Perchloric Acid

Determination of Lead as Chromate in Presence of Perchloric Acid