Extraction and spectrophotometric determination of uranium(VI) withN-phenylcinnamohydroxamic acid

Uranium(VI) reacts withN-phenylcinnamohydroxamic acid to form an orange-yellow complex in the pH range 5.5–8.5. The orange-yellow complex, having the composition of 12 (metal:ligand), is quantitatively extractable into ethyl acetate. The spectrum of the complex exhibits a maximum absorption at 400 nm with a molar absorptivity of 6500 M^–1·cm^–1. The coloured system obeys Beer's law in the concentration range 2–40g·ml^–1 of uranium(VI). The photometric sensitivity of the colour reaction is 0.037 g·cm^–2 of uranium(VI). Most of the common ions do not interfere and the method has been found to be simple, precise, and free from the rigid control of experimental conditions. The method has been applied to the determination of uranium in synthetic matrices and potable water.     

Liquid-liquid extraction of cobalt(II) thiocyanate with hexamethyl phosphoramide: Direct spectrophotometric determination in the organic phase

Summary Use of HMPA in Co(II) thiocyanate colour system gives a simple, sensitive and selective method for the determination of Co(II). Maximum colour intensity is attained in the acidity range of 0.15–0.75M HCl and thiocyanate concentration of 0.5–1.0M. The colour is completely extractable into chloroform, when 2 to 4 ml HMPA is used. The colour system shows maximum absorption at 610 nm. The Beer's law range is 2 to 52g Co/ml with optimum concentration range of 6–48g Co/ml. The molar absorptivity and sensitivity are 1.24 x 10³ l·mole^–1·cm^–1 and 0.047g Co/cm² respectively. The method has been applied to the determination of cobalt in steel.

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Flüssig-flüssig-Extraktion von Kobalt(II)thiocyanat mit Hexamethylpbos-phoramid (HMPA) und spektrophotometrische Bestimmung in der organischen Phase

Zusammenfassung Auf der Grundlage der Farbreaktion von Kobalt(II)thiocyanat mit HMPA wurde eine einfache, empfindliche und selektive Methode zur Bestimmung von Co(II) entwickelt. Das Farbmaximum erhält man in 0,15–0,75M salzsaurer Lösung bei 0,5–1,0M Thiocyanat-Konzentration. Die Färbung ist mit Chloroform vollständig extrahierbar, wenn 2—4 ml HMPA verwendet werden. Die maximale Absorption liegt bei 610 nm. Der optimale Konzentrationsbereich liegt zwischen 6 und 48g Co/ml. Die molare Absorption beträgt 1,24 x l0³l·mole^–1·cm^–1, die Empfindlichkeit 0,047g Co/cm². Die Methode wurde zur Bestimmung von Kobalt in Stahl verwendet.

     

Spectrophotometric determination of osmium using o-hydroxythiobenzhydrazide

Summary Osmium(VI) forms a violet complex witho-hydroxythiobenzhydrazide in the pH range 5.4–6.4. The complex is readily extractable in chloroform to give a violet solution which can be employed for the photometry of osmium. The extract shows maximal absorption at 540–550 nm and obeys Beer's law over the concentration range 1.44–14.40g Os ml^–1.g amounts of osmium can be determined witho-hydroxythiobenzhydrazide in the presence of considerable amounts of diverse ions commonly associated with the metal using EDTA as the masking agent. However, gold should be removed prior to the determination of osmium with the reagent. The molar extinction coefficient of the complex and the Sandell sensitivity are 1.18×10⁴ l mole^–1 cm^–1 and 0.016g cm^–2 respectively.

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Zusammenfassung Osmium(VI) bildet mit o-Hydroxythiobenzhydrazid zwischen pH 5,4 und 6,4 eine violette Komplexverbindung. Diese läßt sich mit Chloroform gut extrahieren. Die violette Lösung eignet sich für die photometrische Bestimmung des Osmiums, zeigt maximale Absorption bei 540–550 nm und entspricht zwischen 1,44 und 14,40g Os/ml dem Beerschen Gesetz. Mikrogrammengen Osmium können so neben erheblichen Mengen verschiedener anderer Begleitionen nach deren Maskierung mit ÄDTA bestimmt werden. Gold jedoch muß vorher entfernt werden. Der molare Extinktionskoeffizient beträgt 1,18×10⁴ l · Mol^–1 · cm^–1, die Empfindlichkeit nach Sandell 0,016g · cm^–2.

     

Simultaneous determination of chromium(VI) and chromium(III) by flame atomic absorption spectrometry with a chelating ion-exchange flow injection system

Summary Simultaneous Determination of Chromium(VI) and Chromium(III) by Flame Atomic Absorption Spectrometry with a Chelating Ion-Exchange Flow Injection System A simple method is described for the simultaneous determination of chromium(VI) and chromium(III) in a flow injection system comprising chelating ion-exchange and flame atomic absorption spectrometry. Sampling rates for 2001 and 1 ml sample volumes were 120 and 60 h^–1 (240 and 120 speciations per hour), respectively. Typical relative standard deviations were 0.52% for Cr(VI) (0.50g ml^–1 and 0.67% for Cr(III) (0.10,g ml^–1) and the corresponding limits of detection were 85 ng ml^–1, and 16 ng ml^–1, respectively.On leave from University of Belgrade.     

Spectrophotometric determination of beryllium and zirconium using chromotrope-2C

Summary Disodium salt of o-carboxyphenylazo chromotropic acid (chromotrope 2C) has been used for the colorimetric determination of microamounts of beryllium and zirconium. The red-violet complexes show maximum absorption at 580 nm and the colour systems obey Beer's law from 0.025 to 0.375 ppm of beryllium and 2 to 12 ppm of zirconium. The optimum concentration ranges are from 0.125 to 0.375 ppm for beryllium and from 4 to 12 ppm for zirconium, where the percent relative errors per 1% absolute photometric error are, respectively, 3.014 and 3.22. The sensitivity of the reactions per cm² are 0.00067 g Be and 0.027 g Zr. The complexes, with the metal to reagent ratio of 11, have instability constants as 2.836 · 10^–6 for beryllium and 6.026 · 10^–6 for zirconium.     

Characterization of airborne particulates by laser microprobe mass analysis

Summary Laser microprobe mass analysis (LAMMA) was applied to characterize aerosol particles collected and separated from 16m to 0.06m by a low pressure cascade impactor. Positive ion LAMMA spectra showed characteristic molecular peaks such as PbCl⁺, a series of Si₂O⁺–Si₂O₄ ⁺ and NaAl₂Si₂O₂ ⁺–NaAl₂Si₂O₅ ⁺, and TiO⁺ in 0.06–0.12m, 0.5–1m and 4–8m fraction, respectively. In the negative ion LAMMA spectra, it was observed that the fragment peaks of sulfate ions were deficient above 2m and those of nitrate ions were deficient under 2m. LAMMA allows remarkable insights into the chemical nature of aerosol particles.

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Charakterisierung luftgetragener Teilchen durch Laser-Microprobe-Massenspektrometrie

Zusammenfassung Laser-Microprobe-Spektrometrie (LAMMS) wurde zur Analyse atmosphärischen Aerosols herangezogen, welches im Korngrößenbereich zwischen 16m und 0.06m mit einem Niederdruckkaskadenimpaktor fraktioniert gesammelt wurde. Positive LAMMS-Spektren zeigten charakteristische molekulare Peaks, wie etwa PbCl⁺, eine Serie von Si₂O⁺–Si₂O₄ ⁺ und NaAl₂Si₂O₂ ⁺–NaAl₂Si₂O₅ ⁺, sowie TiO⁺ in der 0,06–0,12-m,- 0,5–1–m- bzw. 4–8-m-Fraktion. In den negativen LAMMS-Spektren konnten über 2m keine Fragmentpeaks für Sulfationen, unter 2m. keine für Nitrationen beobachtet werden. LAMMS ermöglicht eine bemerkenswerte Einsicht in die chemische Natur von Aerosolteilchen.

     

Photometrische Bestimmung von Bor in hochreinen Chemikalien

Zusammenfassung Bor reagiert in Form des Tetrafluoroboratkomplexes mit dem basischen Farbstoff Methylenblau unter Bildung eines mit 1,2-Dichlorethan extrahierbaren Ionenassoziatkomplexes. Die optimalen Bedingungen für die photometrische Bestimmung von Mikromengen Bor werden ermittelt und das vorgestellte Verfahren hinsichtlich Empfindlichkeit, Genauigkeit und kleinster bestimmbarer Menge charakterisiert.Die Borbestimmung ist im Bereich von 0,25–2,5 g Bor mit einer relativen Standardabweichung von 3,8% für 1,0 g Bor möglich. Der molare Extinktionskoeffizient beträgt ₆₆₅=8,2·10⁴1·mol^–1·cm^–1, die Nachweisgrenze nach Kaiser 0,125 g Bor.Das Verfahren wurde zur Bestimmung von 10^–6 bis 10^–5% Bor in folgenden hochreinen Chemikalien eingesetzt: Methanol, Ethanol, Isopropanol, Aceton, Mineralsäuren, Essigsäure, Ammoniak und Wasserstoffperoxid.

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Photometric determination of boron in high-purity chemicals

Summary Boron reacts with fluoride to form borofluoride which itself reacts with the basic dye methylene blue forming a complex which can be extracted into 1,2-dichloroethane. Optimum conditions were established for the determination of microamounts of boron by an extraction-photometric method. The procedure presented has been characterized with regard to sensitivity, precision and detection limit.Boron can be determined within a range from 0.25 to 2.5 g with a relative standard deviation s _rel=3.8% for 1 g B. The absorptivity is ₆₆₅=8.2·10⁴1·mol^–1·cm^–1, the detection limit according to Kaiser was found to be 0.125 g B.The procedure was used to analyse high-purity chemicals (10^–6–10^–5% B) such as organic solvents, mineral acids, acetic acid, ammonia, hydrogen peroxide etc.

     

Bestimmung von Chrom in menschlichem Serum und Plasma mit der flammenlosen Atomabsorptions-Spektrophotometrie

Zusammenfassung Die bis heute in der Literatur mitgeteilten Werte für Chrom im Serum nüchterner gesunder Probanden unterscheiden sich um Größenordnungen. Die in der vorliegenden Arbeit mitgeteilten Untersuchungen betreffen die analytische Problematik der Chrombestimmung mit Hilfe der flammenlosen Atomabsorptions-Spektrometrie, wobei aufgezeigt wird, daß diese Methodik für die Chrombestimmung in biologischem Material ohne großen statistischen Aufwand zu keiner sicheren Beurteilbarkeit und Interpretierbarkeit der gemessenen Werte führt. Mit Hilfe synthetischer Chromkomplexverbindungen werden die Probleme der Standardaddition zur Chrombestimmung untersucht. Unter Berücksichtigung der Blindwerte und der daraus resultierenden Nachweisgrenze sowie Garantiegrenze für Reinheit, wurde Chrom in einem Standardreferenzmaterial (1569 Brewers yeast [U. S. National Bureau of Standards]) im Rahmen eines Ringversuchs zur Chromanalyse sowie im Serum und Plasma von 41 Probanden bestimmt. Für das Referenzmaterial wurde ein Wert von 45±4 mol/kg (2,3±0,2 g/g) ermittelt. Der Referenzwert betrug 41±1 mol/kg (2,12±0,05 g/g). Im Serum wird eine lognormale Verteilung der Chromkonzentration mit den zentralen Parametern ±_M=132,2 nmol/l (0,72,2 g/l) ermittelt. Im Plasma lagen die Werte zwischen 20 und 30 nmol/l (1–1,5 g/l). Aufschluß, Durchführung der Bestimmung sowie die biologische Bedeutung und Interpretation des Parameters Chrom im Serum und Plasma werden eingehend diskutiert.

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Determination of chromium in human serum and plasma by flame-less atomic-absorption spectrophotometry

Summary Concentrations of Cr in serum of overnight fasting volunteers differ over a wide range in the literature. The investigations of the analytical problems of Cr determination by flameless atomic absorption spectrometry underline the necessity of statistical methods for the interpretation of the measurements of Cr in biological matrices. With nine different synthetic chromium complexes the method of standard addition was investigated. Considering the blank values, the limit of detection and the limit of guarantee for purity, Cr was determined in the standard reference material 1569 brewers yeast (National Bureau of Standards) with 45±4 Mol · kg^–1 (2.3±0.2g·g^–1), compared with the reference data 41±1 Mol·kg^–1 (2.12±0.05 g±g^–1). In serumuuuuu we found a lognormal distribution with the central parameters 132.2 nMol ·1^–1 (0.72.2 g·1^–1). In plasma the values were in the range between 20 and 30 nMol·1^–1 (1–1.5 g·1^–1). The ashing process and the determination are demonstrated and discussed in detail.

     

Extractive spectrophotometric determination of dioxouranium(VI) with the sodium salt of hexamethyleneiminecarbodithioate

The optimum conditions for the extractive spectrophotometric determination of dioxouranium(VI) with hexamethyleneiminecarbodithioate(HMICdt) have been established. Dioxouranium(VI) reacts with this ligand at pH 4.5 to form a yellowish-orange uncharged 12 metal-ligand complex which can be extracted by chloroform. The calibration graph was linear in the range of 1–20 g ml^–1 of dioxouranium(VI) at 335 nm. The molar absorptivity of the extracted species is 5.952×10³ l mol^–1 cm^–1 with Sandell's sensitivity of 0.04 g cm^–2. The average of 10 determinations of dioxouranium was 49.75 g for the samples containing 50 g of U(VI) and the variation from the mean at 95% confidence limit was 49.75±0.5955.     

Extraction-spectrophotometric determination of nickel as Ni-(PAR)2-(CTAB)2 complex in polymetallic sea-bed nodules and steels

A red, water-soluble complex of nickel with PAR can be extracted into chloroform with CTAB at pH 7.0. The system obeys Beer's law upto 0.5 g/ml with a molar absorptivity of 45 200 L·mol^–1·cm^–1 at 540 nm. Job's method of continuous variations revealed that the composition of the extracting species is 1:2:2 for nickel:PAR:CTAB. Based on this extraction, a highly sensitive and selective spectrophotometric method for the determination of nickel in polymetallic sea-bed nodules and in steels, after prior separation of iron and manganese, was developed. The standard deviation was 0.04–0.127 g for 5–25 g of nickel.     

Spectrophotometric Determination of Iron(III) After Separation by Adsorption of its 2-Thenoyltrifluoroacetone Complex on Microcrystalline Naphthalene

Summary A new spectrophotometric method for the determination of iron (III) after adsorption of its red TTA complex onto microcrystalline naphthalene has been developed. Iron(III) reacts with 2-thenoyltri-fluoroacetone in pH range 2.4–5.2 to form a water-insoluble 13 red complex which is easily adsorbed onto microcrystalline naphthalene from its acetone solution. The naphthalene mixture is separated, dried and dissolved in 10 ml dioxane. The red organic phase has a plateau around 480–500 nm while the reagent has no absorbance beyond 420 nm. The system obeys Beer's law over 20–120g iron(III) in 10 ml of dioxane solution or 0.4–2.4 ppm aqueous. The molar absorptivity of the complex species is 3.9×10³·l·mol^–1·cm^–1, while the sensitivity for Fe(III) extends to 1.43×10^–2 g cm^–2 for 0.001 absorbance. Samples containing 80g of iron gave a relative standard deviation of 1.23%. The effects of experimental variables such as pH, amount of reagents, shaking and digestion time, aqueous volume and diverse ions have been examined. The method has been applied to the determination of iron(III) in standard reference and environmental samples and results compared with other standard colorimetric procedures.

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Spektrophotometrische Bestimmung von Eisen(III) nach Adsorption seines 2-Thenoyltrifluoraceton-Komplexes an mikrokristallines Naphthalin

Zusammenfassung Eine neue spektrophotometrische Methode zur Bestimmung von Eisen (III) nach Adsorption seines roten TTA-Komplexes an mikrokristallines Naphthalin wurde ausgearbeitet. Fe(III) reagiert mit 2-Thenoyltrifluoraceton bei pH 2,4-5,2 unter Bildung eines roten, wasser-unlöslichen 13-Komplexes, der sich aus seiner acetonischen Lösung leicht an mikrokristallines Naphthalin adsorbieren läßt. Das Naphthalin-Gemisch wird abgetrennt, getrocknet und in 10 ml Dioxan gelöst. Die rote organische Phase hat ein Adsorptions-Plateau bei 480–500 nm, während das Reagens jenseits 420 nm nicht adsorbiert. Das System entspricht dem Beerschen Gesetz von 20–120g Fe(III) in 10 ml Dioxan-Lösung bzw. 0,4–2,4 ppm in wäßriger Lösung. Die molare Extinktion der Komplexverbindung beträgt 3,9× 10³l·mol^–1·cm^–1. Die Empfindlichkeit für Fe(III) entspricht 1,43×10^–2 g cm^–2 für 0,001 Absorptionseinheiten. Proben mit 80g Fe(III) zeigen eine rel. Standardabweichung von 1,23%. Die Wirkung variabler Versuchsbedingungen pH, Reagensmenge, Zeit, Volumen und diverse Fremdionen wurden geprüft. Das Verfahren wurde an Standardsubstanzen geprüft und seine Ergebnisse mit denen anderer kolorimetrischer Verfahren verglichen.

     

Method comparison study on soot-selective techniques

In a long-term field study at two locations with different air pollution levels several soot-selective measurement techniques were compared with a thermochemical method which measures non-extractable carbon (NEC) detecting the evolved CO₂ by means of coulometric titration. The attenuation measurement technique (aethalometer) and the aerosol photoemission method showed good correlations to NEC for concentrations ranging from 1.6g/m³ to 40.8g/m³. The specific mass absorption coefficient of black carbon with respect to NEC varied between 8.4m²/g and 13.7m²/g with respect to the measurement sites, but the value was found to remain constant at each site independent of seasonal or meteorological variations. The ratio of photoelectric signal to NEC varied between 16 fA·(g/m³)^–1 and 33 fA·(g/m³)^–1 depending on the age of the aerosol. The diurnal variations of that ratio showed strong similarities to the traffic patterns. Additionally a slight temperature dependence of this ratio was found for the aged aerosol with a proportionality factor of – 0.35 fA·(K·g/m³)^–1. With the reflectance measurement technique (smoke shade method) reliable NEC determination was not possible for NEC concentrations 5 g/m³.     

Thorium in man and environment uptake and clearance

The intake and tissue distribution of thorium (^{2 3 2}Th) was studied in an urban (Bombay) population in India. From the analysis of 16 whole diet samples, the average daily intake through food was found to be 2 g (range 0.8–4.3 g·d^–1). The estimated intake through drinking water and inhalation comes out to be 0.03 and 0.02 g per day. From the analysis of human autopsy tissue samples it is observed that the concentration ranges in lungs and bone are 1.5–16 g/kg and 0.2–9.0 g/kg fresh weight respectively. The average urinary concentration is 12 ng/1 (range 7–22 ng/l for 10 samples). Among the different body tissues, pulmonary lymph nodes were found to contain the highest concentration (geometric mean 53.4 g/kg, range 31.4–85.5 g/kg for 6 samples). Analysis of the samples was done by the neutron activation technique. 311.8 keV gamma photons of^{2 3 3}Pa which is the activation product of^{2 3 2}Th, were counted after chemical separation. A 54 cm³ intrinsic Ge detector coupled to 1024-channel analyser was used. Using the average lung content and the daily average intake values of thorium through inhalation, the clearance half-time from lung was estimated.     

Alternative spectrophotometric determination of niobium and tantalum with o-hydroxyhydroquinonephthalein in cationic surfactant micellar media

Summary The alternative and simultaneous spectrophotometric determination of niobium and tantalum was examined by using the colour development between o-hydroxyhydroquinonephthalein (Qnph) and niobium or tantalum in the presence of hexadecyltrimethylammonium chloride (HTAC) in strong acidic media. Beer's law was obeyed up to 10.0 g of niobium and up to 18.0 g of tantalum in a final volume of 10.0 ml. The apparent molar absorption coefficients for niobium and tantalum were 2.18×10⁵ and 2.09×10⁵ l mol^–1 cm^–1 with Sandell's sensitivities of 0.00042 g/cm² niobium at 520 nm and 0.00085 g/cm² tantalum at 510 nm, respectively. The alternative assay of niobium and tantalum was possible by using two methods: Method A — masking method with oxalic acid, Method B — acid adjusting-method using 50% sulfuric acid. These methods were 2–6-times more sensitive than other methods.Application of xanthene derivatives in analytical chemistry. Part XC. Part LXXXIX see ref [1]     

Photometrische Bestimmung kleiner Mengen Gallium mit H?matein

Zusammenfassung Gallium und Hämatein bilden, von pH-Wert und Hämateinkonzentration abhängig, in einer Gleichgewichtsreaktion sowohl einen 11- als auch einen 12-Komplex. Der zwischen den Absorptions-banden beider Komplexe liegende isosbestische Punkt wurde wegen der Unabhängigkeit der Extinktion an dieser Stelle von der Gleichgewichtslage für eine photometrische Galliumbestimmung ausgenutzt. Die Molar-extinktion im isosbestischen Punkt beträgt 3,97 · 10⁴l · Mol^–1 · cm^–1; das Lambert-Beersche Gesetz ist bis mindestens 1,5 g/ml Ga erfüllt. Die rel. Standardabweichung des Verfahrens bei 1 g/ml Ga wurde zu 0,006, die statistische Nachweisgrenze zu 38 ng/ml ermittelt.Für die Bestimmung von Galliumspuren in Aluminium wird ein weitgehend selektives extraktives Anreicherungsverfahren angewandt und an Hüttenaluminium erprobt.

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Photometric determination of small quantities of gallium with haemateinDetermination of gallium in technical aluminium

In an equilibrium reaction, dependent on pH value and haematein concentration, gallium and haematein form 11- and 12-complexes. The isosbestic point between the absorption bands of the two complexes is used for the photometric determination of gallium, because the extinction at this point is independent of the position of the equilibrium. The extinction coefficient amounts to 3.97·10⁴1×Mol^–1×cm^–1. The law of Lambert and Beer is valid at least up to 1.5 g/ml Ga. The relative standard deviation for the determination of 1 g/ml Ga was found to be 0.006, the limit of detection is 38 ng/ml. For the enrichment of traces of gallium in technical aluminium a selective extraction method was used.

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Wir danken Herrn Dr. Pfundt, Leichtmetall-Forschungs-institut der Vereinigte Alumininmwerke AG, Bonn, für die Überlassung von Probenmaterial.     

Spectrophotometric determination of microgram amounts of chromium(VI) and total chromium in waste water

Summary A spectrophotometric method has been developed for the determination of chromium in waste water with 5-Br-PADAP (2-(5-brorno-2-pyridylazo)-5-diethylaminophenol). Chromium(III) forms a blue-purple complex at pH 4.7 upon heating. The color is very stable and is highly sensitive for chromium. At 600 nm it obeys Beer's law in the concentration range of 0–15g of Cr(III) per 25 ml. The sensitivity and molar absorptivity of the reaction are 0.00065g of Cr(III) per cm² and 7.93×10⁴1 · mole^–1 · cm^–1, respectively. The continuous variation and molar ratio methods indicate that chromium forms 12 complex with the ligand.

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Spektrophotometrische Bestimmung von Mikrogramm-Mengen Chrom(VI) und Gesamt-Mengen Chrom in Abwasser

Zusammenfassung Eine spectrophotometrische Methode zur Bestimmung von Chrom in Abwasser mit 5-Br-PADAP wurde ausgearbeitet. Chrom(III) bildet mit 5-Br-PADAP bei pH 4,7 durch Erhitzen einen blaupurpurnen Komplex. Die Farbe ist sehr beständig. Bei 600 nm entspricht die Färbung dem Beerschen Gesetz zwischen 0 und 15g Cr(III)/25 ml. Die Empfindlichkeit der Reaktion beträgt 0,00065g Cr(III)/cm² und die molare Absorption 7.93×10⁴ 1 · mol^–1 · cm^–1. Die Untersuchung nach Job ergab für den Komplex das Molverhältnis Cr:Reagens=12.

     

Nicotinamidoxime as an analytical reagent

Summary Cobalt(II) gives a deep blue colour with nicotinamidoxime in alkaline aqueous-ethylalcoholic medium which has been used with advantage for the spectrophotometric determination of this metal. The optimum p_H for the development of colour is 9.8–11.3 in aqueous-alcoholic (40% v./v.) medium in presence of a large excess of the reagent, at 15–40°C. The colour intensity is measured at 580 m,. Sensitivity is 0.01 g cobalt per cm², while visual identification limit is 0.5 g cobalt per ml (12·10⁶). Beer's law is obeyed in the range of 0.2–20 ppm of the metal, with an optimum range of 2–16 ppm. The colour is stable for about half an hour in the p_N range of 9.8–11.3 and at least one hour in the range of 10.5 to 11.0. On account of the high p_N and alcoholic medium used, most of the cations and anions interfere and, hence, must be removed.Part I: See Z. anal. Chem. 168, 326 (1959).     

Trace element analysis of some shaving powders commonly marketed in Nigeria using instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) technique has been employed viak ₀ approximation method to determine elemental composition of five shaving powders commonly marketed in Nigeria. Fe displayed the highest concentrations in the range 1000–2000 g·g^–1. Na and Zn concentrations were established in the range 200–400 g·g^–1. Heavy elements like Ga, La, Cr, Co, Ag, Ce and Nd concentrations were noted in the lower range of 1–10 g·g^–1 Br, As, Sb, Sm, Eu, W, Cs, Tb, Yb, Hf, Ta, Th and U concentrations were established in even lower traces in the <1 g·g^–1 range. Results obtained for a certified reference material, CANMET BL-1 and CERT (in house) Kaolin standard compared favourably with the literature values thus establishing the results presented for the shaving powders.     

ET-AAS in the Analysis of high-purity mercury

ET-AAS is investigated for the analysis of high purity mercury. Two possibilities are proposed: ET-AAS determination of trace analytes in the presence of high mercury concentrations or after matrix separation by reduction. The ET-AAS analysis of high-purity mercury under optimal instrumental parameters permits fast and reproducible determination of 0.03 gg^–1 Al, Cd and Mn; 0.05 gg^–1 Cu, Co, Cr, Fe, Ni and Pb and 0.2 gg^–1 V. Preliminary mercury matrix reductive separation with ascorbic acid allows determination of 0.005 gg^–1 Cd, 0.02 gg^–1 Cu, Cr and Mn, 0.03 g g^–1 Co, Ni and Pb, 0.05 g g^–1 Al and Fe and 0.1 gg^–1 V, but the reproducibility is lower. The main advantage of the second procedure is that it avoids laboratory and instrument pollution with toxic mercury.