Extraction-spectrometric determination of antimony with triphenyltetrazolium chloride

Summary The optimum conditions for the antimony(V) extraction in strong hydrochloride acid medium as a ternary ion-associated complex with triphenyltetrazolium chloride have been investigated. The extraction constant has been determined with dichlorethene and chloroform (11) (K _ex =3.06×10⁴). A working procedure for the determination of antimony has been developed. Interferences are only caused by iron(III), gold(III), thallium(III) and gallium. The application of the method is demonstrated by the analysis of metallic lead, which has also been carried out with two other methods (AAS and spectrophotometry with crystal violet). The new method is superior in reliability and accuracy. The relative standard deviation of the mean is ± 7.4%.

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Extraktionsspektralphotometrische Bestimmung von Antimon mit Triphenyltetrazoliumchlorid

Zusammenfassung Die optimalen Bedingungen für die Extraktion von Antimon aus stark salzsaurer Lösung als Ionenanlagerungskomplex mit Triphenyltetrazoliumchlorid wurden bestimmt. Die Extraktionskonstante bei Extraktion mit einer Dichlorethan-Chloroform-Mischung (11) beträgt (K _ex =3,06·10⁴). Für die Antimonbestimmung wurde eine entsprechende Methode ausgearbeitet. Nur Fe(II), Au(III), Tl(III) und Ga(III) stören. Die Anwendung der Methode wurde an Hand der Analyse von metallischem Blei demonstriert, die zusätzlich auch nach zwei anderen Methoden (AAS und Spektralphotometrie mit Kristallviolett) durchgeführt wurde. Die neue Methode ist in bezug auf Zuverlässigkeit und Genauigkeit überlegen. Die relative Standardabweichung des Mittelwertes beträgt ± 7,4%.

The first of the authors dedicates this article to his teacher at the University of Saarbrücken, Prof. Dr. E. Blasius, an occasion of his 60th birthday     

Spectrophotometric determination of chloride in plants

This indirect spectrophotometric determination of chloride in plants is based on displacement of thiocyanate from mercury(II) thiocyanate. Thiocyanate is extracted into nitrobenzene as tris(l,10-phenanthroline)iron(II) thiocyanate for measurement at 516 nm. Accuracy and precision are similar to those of the Volhard method but only about 2–200 mg samples are needed.     

Spectrophotometric determination of chloride in non-polar media by the mercury(II) thiocyanate reaction

A simple, rapid and accurate method for the spectrophotometric determination of chloride in non-polar media is described. The method is based on the well-known reaction of mercury(II) thiocyanate with chloride to release thiocyanate, which then reacts with iron(III). The optimum concentrations of reagents for the determination of chloride in 2,2,4-trimethylpentane (iso-octane) and cyclohexane are reported. The molar absorptivity of the complex at 505 nm is 5120 ± 200 dm³ mol^?1 cm^?1 for iso-octane and 5340 ± 340 dm³ mol^?1 cm^?1 for cyclohexane. Beer's Law is obeyed in the range 2 × 10^?7–2 × 10^?5 mol dm^?3 (0.01–1 mg l^?1) chloride.     

Spectrophotometric determination of cobalt in steel with diphenyliodonium chloride

Summary Spectrophotometric Determination of Cobalt in Steel with Diphenyliodonium ChlorideA procedure is described for the determination of cobalt in steel in the range 0.04–0.4% by extraction from a neutral solution into chloroform as the diphenyliodonium tetrathiocyanatocobaltate(II) complex. Absorbance measurements are made directly on the organic extract at 625 nm. Beer's law is obeyed. Iron(III) is masked by fluoride, and copper(II) by thiosulphate; under the described conditions nickel, chromium, manganese, vanadium, molybdenum and tungsten do not interfere at the normal alloying levels in steel.

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Zusammenfassung Ein Verfahren zur Bestimmung von 0,04 bis 0,4% Kobalt in Stahl durch Extraktion des Diphenyljodonium-Tetrathiocyanato-Kobaltats(II) aus neutraler Lösung mit Chloroform wurde beschrieben. Die Absorption wird unmittelbar in der organischen Phase bei 625 nm gemessen. Das Beersche Gesetz ist erfüllt. Fe(III) wird mit Fluorid, Cu(II) mit Thiosulfat maskiert. Unter den angegebenen Bedingungen stören Ni, Cr, Mn, V, Mo und W in Mengen, wie sie sich üblicherweise finden, nicht.

     

Spectrophotometric determination of some dibenzazepines with picryl chloride

A simple and sensitive spectrophotometric method has been developed for the determination of some dibenzazepines, based on reaction with picryl chloride in chloroform medium and measurement at 395 nm. Beer's law is obeyed in concentration ranges 0.1-1.0 microg/ml for imipramine hydrochloride, trimipramine maleate and opipramol dihydrochloride, 0.16-1.6 microg/ml for desipramine hydrochloride and 0.4-2.4 microg/ml for clomipramine hydrochloride. The method was applied successfully to the determination of dibenzazepines in tablets and the results were comparable to those obtained by official procedures.     

Spectrophotometric determination of mercury with thiocyanate and Rhodamine B

Summary Mercury(II) in the presence of a large excess of thiocyanate forms a violet colour with Rhodamine B. The complex formed can be stabilized by addition of poly(vinyl alcohol), and forms the basis for a spectrophotometric method for determination of trace amounts of mercury. The calibration graph for measurement at 610 nm is linear in the range 1–15g of mercury per 25 ml, with a molar absorptivity of 1.1×10⁵l· mole^–1·cm·. The effect of foreign ions has been studied and the method can be applied to the determination of mercury in air with reliable analytical results.

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Spektrophotometrische Bestimmung von Quecksilber mit Rhodanid und Rhodamin B

Zusammenfassung In Gegenwart eines großen Überschusses von Rhodanid bildet Hg(II) mit Rhodamin B eine violette Färbung. Durch Zusatz von Polyvinylalkohol kann dieser Komplex stabilisiert werden und bietet somit die Grundlage für die spektrophotometrische Bestimmung von Hg-Spuren. Die Eichkurve für die Messung bei 610 nm verläuft für 1–15g Hg/25 ml linear. Die molare Absorptivität beträgt 1,1×10⁵ l·mol^–1·cm^–1. Die Fremdionenwirkung wurde untersucht. Das Verfahren kann zur Hg-Bestimmung in Luft verwendet werden.

     

Spectrophotometric determination of mercury(II) with sodium sulfite

A photometric procedure is developed for determining mercury(II) in aqueous media. It is based on the reaction of mercury(II) with sodium sulfite giving a product with an absorption maximum at 230 nm. The optimum conditions are found. The procedure allowed 0.5 to 13.0 μg/mL of mercury(II) to be determined for 1 min. The effect of some metal cations is estimated.     

Spectrophotometric flow injection determination of chloride in ethanol

A flow injection procedure is described for the spectrophotometric determination of chloride in ethanol, based on the mercury(II) thiocyanate—iron(III) reaction. Effects of reagent composition and ethanol content of the sample are investigated in detail. The proposed system can analyse 120 samples of ethanol (94–100% v/v) per hour, with a relative standard deviation lower than 1%, when the chloride content ranges from 0.1–6.0 ppm. Recoveries of ca. 96% are found.     

Spectrophotometric determination of chromium with Iodonitrotetrazolium chloride and Tetrazolium Violet

The interaction of Iodonitrotetrazolium chloride and Tetrazolium Violet with chromium(VI) has been studied and the formation of ion-associates with a 1:1 composition in hydrochloric acid medium established. Extraction photometric methods for determination of chromium in steels and soils have been developed.     

Spectrophotometric determination of sulfite with soluble mercury(II) compounds

Sulfite ion reacts with mercury(II) ion in acid solution to form the mercury(I) ion. The reaction is rapid and quantitative. The mercury(I) ion absorbs at 237 nm with a molar

5. Beer's law Data for Sulfite Complexes of Covalent Mercury(II) Compounds

SO2 (ppm)	?HgCl2a	?HgBr2	?Hg(Ac)2b	?Hg(SCN)2
2.0	12,500	10,000	10,000	9,200
4.0	12,500	11,500	10,000	9,000
6.0	12,500	11,500	10,000	9,200
8.0	12,000	11,000	10,500	9,800

a

Molar absorptivity based on sulfite ion at 230 nm. Solution was 6.86 buffer.

b

Mercuric acetate solutions seemed to be somewhat unstable. absorptivity of about 25,000. The absorbance is linear over a range of approximately 0.5–5.0 ppm as SO₂. Covalent mercury(II) compounds form a complex with sulfite, Hg(SO₃)₂^2?, which absorbs at 230 nm and shows a linear response over a range of 1–8 ppm as SO₂.

     

氯化硝基四氮唑蓝分光光度法测定功能性食品中的维生素C

研究了在碱性介质中利用维生素C与氯化硝基四氮唑蓝反应生成蓝色化合物的性质,建立了分光光度法测定维生素C含量的新方法.该体系的最大吸收波长为630 nm,摩尔吸光系数为1.7×104 L/mol/cm,维生素C含量在2～20 mg/L范围内符合比尔定律,检出下限为0.25 mg/L.该方法已用于功能性食品中维生素C的测定.     

Spectrophotometric determination of ruthenium after extraction of perruthenate with benzyltributylammonium chloride

A simple and convenient extractive spectrophotometric method for the determination of ruthenium has been developed. It is based on the oxidation of the different ruthenium (II, III or IV) species to perruthenate with potassium periodate at pH 7.8. The perruthenate is then extracted with benzyltributylammonium chloride in chloroform followed by direct spectrophotometric measurements at 342 and 380 nm. The optimum concentration range was found to be 0.1–5 mg l^–1, the standard deviation ±2.1%. The method has been successfully applied to the determination of ruthenium in organoruthenium compounds.     

新试剂光度法测定废水中氯化十六烷基吡啶的研究

研究了新试剂4,4′-二[3-(4-苯基-2-噻唑基)三氮烯基]联苯(BPTTBP)与氯化十六烷基吡啶(CPC)的显色反应。在NaOH碱性介质中,试剂与CPC发生显色反应,形成紫色离子缔合物,最大吸收波长592 nm。试剂BPTTBP与CPC的缔合比为1∶1,其表观摩尔吸光系数为2.84×104L.mol-1.cm-1,CPC量在0~1.0×10-5mol/L范围内服从比尔定律。方法可直接用于废水中微量CPC的测定。     

Spectrophotometric determination of iron in zirconium metal and in zirconyl chloride

Iron, present in zirconium metal or in zirconyl chloride, may be determined spectrophotometrically in 1 : 1 hydrochloric acid solution without prior separation from the zirconium. In a 1 : 1 hydrochloric acid solution, at the solubility limit of zirconyl chloride (0.28 g zirconium per 25 ml), 20 p.p.m. of iron may be detected.When smaller amounts of iron are to be determined (4 p.p.m.), a larger starting sample (5 g) of zirconium is crystallized from a 3 : 1 hydrochloric acid solution which reduces the lower limit of detection of iron to 4 p.p.m.     

Spectrophotometric determination of aluminium with Chromal Blue G in the presence of cetyltrimethylammonium chloride

Summary Spectrophotometric Determination of Aluminium with Chromal Blue G in the Presence of Cetyltrimethylammonium Chloride Chromal Blue G (C. I. 43835) in the presence of cetyltrimethylammonium chloride is proposed for the spectrophotometric determination of microgram amounts of aluminium. The stoichiometric ratio of aluminium to Chromal Blue G is 14. Beer's law is obeyed from 0.01 to 0.16 ppm of aluminium. The molar absorptivity is 1.62×10⁵1·mole^–1·cm^–1 at 660 nm.     

Spectrophotometric determination of nitrite and nitrate in doped potassium chloride crystals

Summary KCl crystals, doped in the melt with KNO₂ or KNO₃, contain both NO₂ ^– and NO₃ ^– ions. Spectrophotometric methods are described for the determination of the admixture concentration after dissolving the crystals. Nitrite is determined by colorimetry of an azo dye formed in methanol-water-HCl medium from p-nitroaniline and -naphthylamine. The absorption is proportional to the nitrite concentration in the range of 5 · 10^–6 to 5 · 10^–5 M NO₂ ^– UV absorption measurement is employed for the spectrophotometric determination of nitrate, Beer's law being obeyed between 3 · 10^–5 and 3 · 10^–4 M NO₃ ^– at 220 nm. Here, nitrite is removed by adding sulfamic acid, and correction is made for chloride. Some results on nitrite- and nitrate-doped crystals are given.

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Zusammenfassung KCl-Kristalle mit zur Schmelze zugesetztem KNO₂ oder KNO₃ enthalten sowohl NO₂ ^–- wie NO₃ ^–-Ionen. Spektrophotometrische Methoden werden beschrieben zur Bestimmung des Gehaltes dieser Zusätze nach Lösen der Kristalle. Nitrit wird bestimmt durch Colorimetrieren einer Azoverbindung aus p-Nitranilin und -Naphthylamin in einem Methylalkohol-Wasser-Salzsäure-Gemisch. Die Absorption ist dem Nitritgehalt von 5 · 10^–6 bis 5 · 10^–5 m NO₂ ^– proportional. Die UV-Absorption wird zur spektrophotometrischen Bestimmung des Nitrats verwendet. Das Beersche Gesetz ist hier zwischen 3 · 10^–5 und 3 · 10^–4 m NO₃ ^– gÜltig (bei 220 nm). Nitrit wird dabei durch Zusatz von Sulfaminsäure entfernt, und es wird fÜr Chloride korrigiert. Einige Ergebnisse an Kristallen mit Nitrit- bzw. Nitratzusatz werden angefÜhrt.

     

Spectrophotometric determination of gallium(III) with carminic acid and hexadecylpyridinium chloride

A Spectrophotometric method is proposed for determining dipyridamole in pure form and in pharmaceutical preparations. Chromotrope 2B was used as a charge-transfer complex forming agent with absorption maximum 40 nm red shifted relative to the chromotrope 2B itself. The variables affecting the formation of the C.T. complex were studied and optimized. Linear calibration graphs were obtained up to 60 g ml^–1 at room temperature. The method was found to be accurate, precise and can be successfully used for authentic and pharmaceutical preparations in the working range up to 600 g.A conductimetric method using phosphotungstic acid as ion-associate forming agent is proposed. The relative average error is 1–2%. Water-ethanol (12) mixture was used as solvent. Excellent recoveries and low standard deviations were obtained. Working ranges are 40–260 mg and 35–110 mg for pure dipyridamole and tablets, respectively.On leave from Department of Chemistry, Faculty of Science, Allepo University, Allepo, Syria     

Spectrophotometric determination of oxalic acid in presence of glyoxylic acid and chloride

Glyoxylic acid gives a yellow 1:1 complex, [FeCHOCOO]²⁺ with iron(III). The dissociation contant, measured by two spectrophotometric methods, is K = 9.7 ± 1 mol l^?1. Oxalic acid gives two complexes with iron(III) which absorb in the same range around 400 nm. With appropriate precautions and corrections, oxalic acid concentrations of about 10^?1–10^?2 M can be determined in the presence of glyoxylic acid and chloride.