Direct determination of nickel traces on modified cellulose by diffuse reflection spectroscopy and using chromaticity characteristics

Diffuse reflection spectroscopy has been used for the direct determination of nickel traces after preconcentration on cellulose (Cel). The experimental parameters (optical characteristics, acidity of aqueous solution, shaking time, volume of aqueous solution, nickel and tartaric ion concentrations, etc.) affecting sorption of nickel species with immobilized dimethylglyoxime (DG) and benzyldioxime (BD) have been optimized. Diffuse reflection coefficient and chromaticity characteristics of the nickel sorbates indicated the same dependence on studied factors, but their sensitivity is different. The linear relations of variations of these quantities with the nickel contents were determined. Detection limits were 0.1 μg/mL and 0.2 μg/mL for BD and DG, respectively. The procedures were used for the analysis of natural and waste waters.     

Direct determination of traces of beryllium with eriochrome cyanine R by diffuse reflection spectroscopy using chromaticity functions

Chromaton-N-super and Silasorb C18 (SMT C18) were compared as solid supports for the direct determination of the immobilized beryllium complexes with eriochrome cyanine R by diffuse reflection spectroscopy. The advantage of Silasorb C18 was shown. A detection limit of 0.0002 microg mL(-1) could be reached in a 100-mL sample. The method was used for the analysis of real water samples.     

Improvement of direct determination of trace nickel in environmental samples by diffuse reflection spectroscopy using chromaticity characteristics

Cellulose and chromaton-N-super as solid supports for direct determination of the immobilized nickel complexes with dimethylglyoxime and benzyldioxime by diffuse reflection spectroscopy were compared. The advantage of chromaton-N-super with use of benzyldioxime is shown. Detection limit is 0.02 μg/mL. The proposed method was applied for the analysis of soil. Received: 12 April 1999 / Revised: 10 December 1999 / /Accepted: 15 December 1999     

Improvement of direct determination of trace nickel in environmental samples by diffuse reflection spectroscopy using chromaticity characteristics

Cellulose and chromaton-N-super as solid supports for direct determination of the immobilized nickel complexes with dimethylglyoxime and benzyldioxime by diffuse reflection spectroscopy were compared. The advantage of chromaton-N-super with use of benzyldioxime is shown. Detection limit is 0.02 microg/mL. The proposed method was applied for the analysis of soil.     

Simultaneous determination of nickel and cobalt traces by neutron activation analysis

Nickel and cobalt traces may be determined by measuring the ⁵⁸Co and ⁶⁰Co activities produced in a nuclear reactor. Solvent extraction of cobalt, and γ-spectrometry on the extracted phase allow a rapid and simple analysis of both metals. The method is applied to the determination of nickel (100–0.2 p.p.m.) and cobalt (0.15–0.001 p.p.m.) in various materials (petroleum, polyphenyls, aluminium).     

Direct determination of enantiomeric purity using CPL spectroscopy

The dependency of the Circular Polarization of the Luminescence (CPL) on the handedness of the excitation light potentially provides a means to determine enantiomeric purity. In literature two procedures have been outlined for such determinations, but as yet they have not been experimentally tested. These procedures, along with a third one we propose here, are evaluated from theory and confronted with experiment. It appears that the CPL technique provides a valuable tool for the determination of enantiomeric purity. The scope and limitations of the method are discussed.     

Direct and rapid determination of sulphate in environmental samples with diffuse reflectance Fourier transform infrared spectroscopy using KBr substrate

The feasibility of employing diffuse reflectance Fourier transform infrared spectroscopy (DRS-FTIR) as a sensitive tool in the submicrogram level determination of sulphate (SO₄²⁻) was checked in this work. This paper presents the development of a new, rapid and precise analytical method for ppb levels of sulphate (SO₄²⁻) in environmental samples like coarse and fine aerosol particles, dry deposits and soil. The determination of submicrogram levels of sulphate is based on the selection of a quantitative analytical peak at 617 cm⁻¹ among the three observed vibrational peaks and preparing calibration curve using different known concentrations of sulphate by diffuse reflectance-Fourier transform infra red spectrometric (DRS-FTIR) technique. Pre-weighed and ground IR grade KBr was used as substrate over which remarkably wide range of known concentration of sulphate was sprayed and dried. The dried sample was analysed by DRS-FTIR. Three calibration curves for three different concentration ranges of sulphate were prepared for samples containing low and relatively higher sulphate contents. The relative standard deviation (n = 8) for the sulphate concentration ranges, 2.5-35.5, 25.5-165, 55-1000 μg/0.5 g KBr, as used to prepare calibration curves, were 2.4%, 2.1% and 1.5%, respectively. The relative standard deviation for the sulphate concentration in real samples were found to be in the range, 3.11-5.76% (n = 16), 4.05-7.75% (n = 16) and 1.48-3.52% (n = 10) for aerosol, dry deposits and soil, respectively. The LOD of the method is 0.20 μg/g SO₄²⁻. The F- and t-tests were performed to check the analytical quality assurance test. The noteworthy feature of the reported method is the non-interference of any of the associated anions and cations. The results were compared with that of ion-chromatographic method with high degree of acceptability. The method can be applied in wide concentration ranges. A method for sulphate determination was introduced that did not require pretreatment of samples. This method employed the direct determination of the sulphate. The method is reagent less, nondestructive, very fast, repeatable, and accurate and has high sample throughput value.     

An approach by using near-infrared diffuse reflectance spectroscopy and resin adsorption for the determination of copper, cobalt and nickel ions in dilute solution

Near-infrared spectroscopy (NIRS) has been proved to be a powerful analytical tool and used in various fields, it is seldom, however, used in the analysis of metal ions in solutions. A method for quantitative determination of metal ions in solution is developed by using resin adsorption and near-infrared diffuse reflectance spectroscopy (NIRDRS). The method makes use of the resin adsorption for gathering the analytes from a dilute solution, and then NIRDRS of the adsorbate is measured. Because both the information of the metal ions and their interaction with the functional group of resin can be reflected in the spectrum, quantitative determination is achieved by using multivariate calibration technique. Taking copper (Cu²⁺), cobalt (Co²⁺) and nickel (Ni²⁺) as the analyzing targets and D401 resin as the adsorbent, partial least squares (PLS) model is built from the NIRDRS of the adsorbates. The results show that the concentrations that can be quantitatively detected are as low as 1.00, 1.98 and 1.00 mg L⁻¹ for Cu²⁺, Co²⁺ and Ni²⁺, respectively, and the coexistent ions do not influence the determination.     

Analytical use of modified catalytic reaction rate: Kinetic determination of traces of aminopolycarboxylic acids,nickel and zinc

Summary The inhibitory effect of EDTA (or EGTA) on the copper-catalysed oxidation of 4,4-dihydroxybenzophenone thiosemicarbazone by hydrogen peroxide has been studied. The reaction is followed spectrophotometrically at 415 nm. EDTA and EGTA at the 10^–6 M level can be determined kinetically by two methods. The accuracy and precision are about 1% and 1.5% respectively. The method can be applied to the indirect determination of nickel and zinc in the range 130–300 ng/ml with acceptable results, by an indirect kinetic method.

---

Analytische Anwendung einer modifizierten katalytischen Geschwindigkeitskonstante: kinetische Bestimmung von Spuren von Aminopolycarbonsäuren, Nickel und Zink

Zusammenfassung Die hemmende Wirkung von EDTA (oder EGTA) gegenüber der kupferkatalysierten Oxydation von 4,4-Dihydroxybenzophenonthiosemicarbazon durch Wasserstoffperoxid wurde untersucht. Die Reaktion wurde bei 415 nm spektrophotometrisch verfolgt. EDTA und EGTA können in 10^–6 M Größenordnung mit zwei verschiedenen Methoden kinetisch bestimmt werden. Die Genauigkeit beträgt etwa 1% bzw. 1,5%. Das Verfahren kann zur indirekten Bestimmung von Nickel und Zink in der Größenordnung 130–300 ng/ml mit annehmbaren Ergebnissen herangezogen werden.

     

Direct determination of traces of total oxygen in naphthas

The low oxygen content and volatility of naphthas make existing methods for determining traces of oxygen and oxygen compounds m naphthas unreliable The SCHÜTZE method has been modified to include a magnetically controlled spiral sample container from which a 5-g sample can be pyrolyzed safelv by cxpellmg it a few drops at a time In the range of 100 to 200 p.p m oxygen, the standard deviation and the average error for synthetic Samples are about 10% of the oxygen present The deviation from the mean for routine samples containing less than 100 p p.m. oxygen is about ± 20%     

Preconcentration of nickel using cellulose ion exchangers for electrothermal atomic absorption spectrometric determination

Nickel (? 0.11 μg l^?1) in water samples is determined by graphite furnace atomic absorption spectrometry after preconcentration from 3 l of sample on a column of Cellex CM and elution with 20 ml of 2 M nitric acid. High concentrations of some other cations interfere, but the concentrations present in river and tap waters have no effect. The use of Cellex P is also studied.     

Direct determination of nanogram amounts of iodine by atomic-absorption spectroscopy using a graphite-tube atomizer

The direct determination of iodine by AAS at its 183.0 and 178.2 nm resonance lines by using a small graphite-tube atomizer, electrodeless discharge-lamp source and vacuum monochromator is described. Optimum conditions for the determination of iodine have been established; similar sensitivity is obtained when iodide or iodate samples are examined. With 10 mul aqueous samples sensitivities (for 1% absorption) of 4 x 10(-10) g and 2 x 10(-10) g of I were obtained at 183.0 and 178.2 nm respectively; a detection limit of 2 x 10(-10) g was observed at both lines. Non-specific molecular absorption from common inorganic salts causes interference with the determination; the iodine non-resonance line at 184.4 nm may be employed to correct for this interference when moderate amounts of common salts are present.     

Sampling depth in infrared diffuse reflection spectroscopy of undiluted samples

Diffuse reflectance of strongly absorbing sample layers is calculated in dependence of their thicknesses from the Kubelka-Munk theory. The results are compared to experimental ones from varnish layers on reflecting metal substrates.     

Direct determination of uranyl ion by nanosecond dye-laser spectroscopy

A sensitive and selective technique for the detection and assay of the uranyl ion is described. The technique is based upon the measurement of the lumi.     

Direct colorimetric determination of nickel with furildioxime

Summary An extractive method for the rapid colorimetric determination of nickel as the yellow furildioxime complex in chloroform is presented. The development of the method into one based on a single extraction without the need of preliminary separations, pH adjustment, and after-treatment of the extract has been made possible by buffering the aqueous phase, and masking interfering elements. The narrow range in alkalinity essential for quantitative extraction in the acetate-tartrate medium is maintained by the addition of borate. Interference from cobalt in 10-fold, and copper in 100-fold excess of nickel is eliminated by the use of thiosulphate and ethylene diamine as masking agents. Iron may be present in 2000-fold, manganese and titanium in 400-fold, chromium, molybdenum, palladium, tin, vanadium, zinc, and zirconium in 200-fold excess, making the method suitable for determination of nickel in quantities down to 0.5 g in rocks, steels, ores, and other materials.

---

Direkte colorimetrische Bestimmung von Nickel mit Furildioxim

Zusammenfassung Das Verfahren beruht auf der Extraktion des gelben Nickel-Furildioxim-Komplexes mit Chloroform. Durch Pufferung der wäßrigen Phase und Maskierung von störenden Fremdionen kann die Bestimmung mit nur einer Extraktion durchgeführt werden, ohne Vortrennungen, pH-Einstellung und Nachbehandlung. Der enge Alkalitätsbereich, der für eine quantitative Extraktion im Acetat-Tartrat-Medium erforderlich ist, wird durch Zusatz von Borat gewährleistet. Störungen durch die 10fache Menge an Kobalt und die 100fache an Kupfer werden durch Thiosulfat und Äthylendiamin beseitigt. Eisen kann in 2000fachem, Mangan und Titan in 400fachem, Chrom, Molybdän, Palladium, Zinn, Vanadium, Zink und Zirkonium in 200fachem Überschuß zugegen sein. Das Verfahren eignet sich zur Nickelbestimmung bis herab zu 0,5 g in Gesteinen, Erzen, Stahl und anderen Materialien.

---

---

The writer would like to express his sincere thanks to Prof. K. von Gehlen for furthering this work by making funds and laboratory facilities available, and to the Deutsche For schungsgemeinschaft for a grant to K. von Gehlen.     

Direct determination of nitrite traces in high ionic-strength samples by electrostatic ion chromatography using diluted acid solutions as eluent

An ion-chromatographic (IC) system with high selectivity for separation of nitrite is described. It is analogous to the EIC (electrostatic IC) previously reported and was established using 3-(N,N-dimethylstearylammonio)propanesulfonate (C23H49NO3S, a sulfobetaine type of zwitterionic surfactants) as the stationary phase and dilute aqueous HCl solutions as the mobile phase. Five inorganic anions, sulfate, chloride, bromide, nitrate, and nitrite were chosen as the model analytes and were analyzed using this EIC system. Sulfate was always eluted first, followed by chloride, bromide and nitrate. Nitrite, however, could be eluted either before or after nitrate, depending on the concentration of HCl in the eluent. An elution order nitrate< nitrite was always obtained simply by using >3 mmol L(-1) HCl as the eluent. For nitrite the detection limit was better than 2.1 x 10(-7) mol L(-1) (100 microL sample injection volume, S/N=3, UV at 210 nm). Bromide and nitrate could also be separated under these HPLC conditions. The detection limit for bromide was 7.2 x 10(-8) mol L(-1) and for nitrate 6.5 x 10(-8) mol L(-1). Both nitrite and nitrate in real seawater samples were successfully determined with direct sample injection using this EIC system.     

Simultaneous spectrophotometric determination of traces of cobalt,nickel and copper with dithio-oxamide

The cobalt, nickel and copper complexes of dithio-oxamidc have been characterized in terms of color, effect of pH, structure in solidion, order of addition of reagents, adherence to Beer's law and sensitivity. The reactivity of the reagent to other ions has been reported. A method for the simultaneous spectrophotometric determination of cobalt, nickel and copper has been developed. the results of the application of this procedure to synthetic samples and to several National Bureau of Standards Samples are given.     

Direct determination of traces of lanthanide ions in aqueous solutions by laser-induced time-resolved spectrofluorimetry

The most convenient spectral regions for dye laser excitation are presented for seven lanthanide ions. Fluorescence lifetimes are given for 0.5 M sulphuric acid and 3 M potassium carbonate media. With the excimer-pumped dye laser, the detection limits are in the range 0.1 μg 1^?1 (Eu) to 50 μg 1^?1 (Gd). Examples of the resolution of mixtures are given.