Kinetic fluorimetric determination of Cu(II) and Zn(II) by their incorporation reactions into a water-soluble porphyrin

Kinetics of incorporation of Cu, Zn, Fe, Co, Ni and Mn divalent ions into coproporphyrin-I in imidazole buffer solution, pH 7.0, has been studied by monitoring the decrease in fluorescence intensity of the free base porphyrin. All reactions followed simple second-order rate law, the rate constants being decreased in the order Zn > Cu > Co > Fe > Mn, Ni. the kinetic fluorimetric method for the determination of Cu(II) and Zn(II) using their incorporation reactions into the porphyrin was developed. Initial rate and fixed-time methods were used to construct calibration graphs over the range 0-1.0 x 10(-5)M of both metals. The analytical characteristics of the method and effect of foreign ions were determined. In the presence of sodium thiosulphate as the masking reagent the determination of micromolar concentrations of Zn in the presence of a 10-fold excess of Cu is possible.     

Determination of Cu, Zn, Fe, Ni and Cd by flame atomic absorption spectrophotometry after preconcentration by Escherichia coli immobilized on sepiolite

A method for the determination of Cu, Zn, Fe, Ni and Cd by flame atomic absorption spectrophotometry (FAAS) after preconcentrating on a column containing Escherichia coli immobilized on sepiolite has been developed. Optimum pH values, amount of adsorbent, elution solution and flow rate have been obtained for the elements studied. The effect of interfering ions on the recovery of the analytes has also been investigated. Recoveries of Cu, Zn, Fe, Ni and Cd by E. coli immobilized on sepiolite were 99.1+/-0.6, 98.2+/-0.6, 98.1+/-0.5, 97.2+/-0.8 and 98.2+/-0.4% at 95% confidence level, respectively. The adsorption capacity of E. coli immobilized on sepiolite was found as 0.148, 0.064, 0.098, 0.134 and 0.088 mmol/g for Cu, Zn, Fe, Ni and Cd, respectively. The proposed method was applied to the determination of trace metals in alloys (NBS SRM 85b). Trace metals have been determined with relative error lower than 10%.     

Micelle mediated extraction of titanium and its ultra-trace determination in silicate rocks

A highly sensitive method for extractive spectrophotometric determination of titanium in silicate rocks is described. Titanium in the range 0-10 microg as TiO2 is extracted into benzene or toluene by the formation of a ternary complex of the metal with thiocyanate (SCN-) and cetyltrimethylammonium bromide (CTA) in the ratio 1:2:2. A deep yellowish-orange ternary complex thus formed is suitable for the determination of titanium at wavelength 421 nm. The optimum colour intensity of this ternary complex was attained when the complex was extracted from an aqueous solution having concentrations of thiocyanate and HCl, in the range, 1.5-2.5 and 1-5 mol L(-1), respectively. The molar absorptivity and Sandell's sensitivity of the extracted species were found to be 1.1-1.0x10(5) L mol(-1) cm(-1) and 0.47 ng cm(-2) (referred to titanium), respectively, at lambda(max) of 421 nm. Except Fe3+, Nb5+ and V5+, no interference was encountered in the estimation of titanium. While up to 10 mg L(-1) Nb and V did not interfere in the determination of titanium, the interference of Fe(3+) was eliminated by reducing it to Fe2+ using SnCl2 solution. The method is highly sensitive and selective. The results obtained for titanium estimation in a host of silicate rock samples have been found to be highly reproducible, accurate and favourably comparable with certified values of reference materials and those obtained from standard methods.     

Determination of trace elements in food by neutron activation analysis

Neutron activation analysis (NAA) methods have been developed for the determination of major, minor and trace elements in duplicate diets and individual food items. These include a cyclic instrumental NAA (CINAA) method for measuring Se content through its short-lived nuclide^77mSe; epithermal INAA (EINAA) for I and As; conventional INAA for Br, Ca, Cl, Co, Cr, Fe, K, Mg, Mn, Na, Rb, Sb, Sc, Sn and Zn; combination of EINAA and INAA for Al; radiochemical NAA (RNAA) for As, Au, Co, Cu, Fe, Hg, Mo, Sb, Se and Zn; and preconcentration NAA (PNAA) for U and Th. Accuracy of measurements have been evaluated by analyzing a number of biological and diet reference materials. Multielement concentrations of diets and foods have been measured by these methods.     

高效液相色谱光度法测定痕量铜、锌、铁、锰的磺化四苯基卟啉配合物

本文用磺化四苯基卟啉作柱前衍生试剂,研究了试剂与铜(Ⅱ)、锌(Ⅱ)、铁(Ⅲ)及锰(Ⅱ)的络合反应。在ODS柱上,用乙腈-水(40:60,V/V)作流动相,溴化四丁基铵作离子对试剂,在420nm波长处进行光度检测。提出了离子对反相高效液相色谱快速分离及测定痕量铜、锌、铁及锰的新方法。检测下限为(×10^-3ppm):Mn 3.6、Fe 1.8 、Zn 0.93、Cu 0.70。应用于植物样品中痕量铜、锌、铁及锰的测定,分析结果与标准参考值相符。     

Application of stripping voltammetry method for the analysis of available copper,zinc and manganese contents in soil samples

Determination of copper (Cu), zinc (Zn) and manganese (Mn) micronutrients in soil samples have been studied for an efficient fertiliser application. Plant-available micronutrients of soils were extracted with DTPA extraction procedure, then differential pulse stripping voltammetry (DPSV) and square wave stripping voltammetry (SWSV) methods were performed with inexpensive and disposable pencil graphite electrode for determination of Cu(II), Zn(II) and Mn(II). Parameters such as deposition potential, deposition time, pH and concentration of the supporting electrolyte were optimised for these ions. Under optimised conditions, the limits of detection were found as 0.01 mg L^?1 for Cu(II) and 0.02 mg L^?1 for Zn(II) and 0.25 mg L^?1 for Mn(II). Relative standard deviation (%RSD) was 6.80, 8.86 and 3.29 for Cu(II), Zn(II) and Mn(II), respectively. The experimental study was conducted using a flame atomic absorption spectroscopy. The described stripping voltammetry methods were successfully applied for the determination of Mn(II), Cu(II) and Zn(II) in soil samples.     

Mutual interferences of elements in the atomic-absorption analysis of human hairs

Mutual interferences of elements in the atomic-absorption analysis of solutions of human hairs were estimated using mathematical procedures of experimental design. The effects of Na, Cl, Ca, Fe, Zn, and Pb, whose concentrations in hairs vary within a wide concentration range, on the results of the determination of Cu, Cd, K, Fe, Zn, and Pb were examined. An interpretation of the obtained models was given. Two methods for taking into account mutual interferences were proposed and approved: (1) the use of multielement reference samples whose chemical compositions are prescribed based on the proposed models and (2) the representation of calibration curves in the form of multidimensional polynomials     

Preconcentration and Determination of Metal Species at Polypyrrole Modified Glassy Carbon Electrodes

Metal species can be extracted/preconcentrated onto electropolymerized polypyrrole film electrodes without deliberate incorporation of chemically active counterions. Silver species preconcentrated on polypyrrole film can be determined electrochemically. The effects of polypyrrole film coverage, electropolymerization conditions,solution composition and the presence of other species have been investigated. Experimental results showed that the anodic peak current for incorporated silver species was proportional to silver concentration in solution in the range from 2 to 150 μM. The detection limit was estimated to be about 0.2 \μM (20 ppb). Most of the metal ions studied, including Ni, Cd, Pb, Zn and Fe, did not show obvious interference on the determination. Cu and Hg were also extracted onto polypyrrole film electrodes. Polypyrrole film electrodes were reuseable. The mechanism involved in the preconcentration was also investigated.     

Extractive concentration of platinum-group elements and their determination by atomic-absorption spectrophotometry

The extraction of Pt, Pd, Ir, Rh, Ru, Ag, Au, Co, Cu, Ni and Fe with n-octylaniline has been investigated. Noble metals are extracted 10(3)-10(4) times better than Cu, Ni, Co and Fe. A method of determination of Pt, Pd, Ir, Rh and Ru is proposed. They are first separated from Cu, Ni, Co and Fe by means of extraction (and then determined, in either the aqueous or organic phase, by atomic-absorption spectrophotometry. The atomic absorption of platinum metals (with the exception of Pd) is affected by other elements of the platinum group and by non-noble metals. La(NO(3))(3) and Nd(NO(3))(3) lower the limit of detection for Pt, Rh, Ir and Ru and inhibit the effect of Co, Cu, Ni, Fe, Bi, Zn, Na, etc. on their determination. Lanthanum and neodymium chlorides and sulphates produce a similar effect but only on the determination of Pt and Rh. The coefficient of variation of the determination, in both phases, is within 2-6.8%.     

Zerstörungsfreie aktivierungsanalytische Bestimmung von Mikro- und Ultramikromengen Indium in Reinstthallium und Thalliumverbindungen

Two non-destructive neutron activation methods has been described for the determination of indium in thallium metal and thallium compounds. The sensitivity of the first method based on^114mIn corresponds to 1×10^?6g (standard deviation 4,5–8%). The second method (by means of^116mIn) permits the determination of ultramicro amounts of indium up to 5×10^?11g with a standard deviation of 15%. The influence of many elements (such as Ga, Cu, Al, Cd, Zn, Pb, Ca, Mg, Bi, Fe) has been examined. The methods have been applied to the determination of indium in thallium metal, oxide, nitrate, sulphate and chloride. The data obtained agreed whith those of the spectrochemical determination.     

Benzoxazolylacrolein derivatives as ligands for extraction atomic absorption analysis

The extraction of chelate and ion-association complexes formed by various metal ions and two new organic reagents (derivatives of benzoxazolylacrolein) has been investigated in order to evaluate the possibilities for analytical application. The composition of the extracted species and their conditional extraction constants are given. Two simple extraction procedures for flame atomic absorption analysis of high purity lead salts have been developed. The proposed methods permit determination of (a) 1 × 10^–5% Co, Fe and Ni and 5 × 10^–6% Cu and Zn and (b) 1 × 10^–5% Pd and 5 × 10^–6% Ag and Au, with relative standard deviations in the range 4–8%.     

X-ray fundamental parameter methods for the determination of some elements in hydrocarbons by WDXRF

Summary X-ray fundamental parameter methods have been applied to the determination of some elements such as Fe, Ca, Zn, Ba and S in solutions of hydrocarbons analysed by means of a wavelength dispersive spectrometer. A comparison is carried out for methods with standards as well as without standards. The influence of different kinds of standards on the results has been investigated. The use of aqueous salt solutions has led to more accurate values than the use of solid standards. The same random errors have been obtained for both kinds of standards. Results obtained without standards are slightly less accurate than those obtained with aqueous standards.     

Substoichiometric isotope dilution analysis of iron in biological materials by the 8-quinolinol-extraction

A highly precise and accurate method for the determination of minor amounts of iron by substoichiometric isotope dilution analysis is described. The constant amount of Fe(III) is substoichiometrically extracted with 2·10⁻⁴M oxine in chloroform from the aqueous phase of pH 9.2–10.0 containing 6·10⁻³M tartrate. The interfering ions such as Mn(II), Co(II), Ni(II), Cu(II), and Zn(II), can be removed by the preliminary extraction of Fe(III) from 7.5M hydrochloric acid solutions into isopropyl ether. The present method has been applied to the determination of iron in biological standard reference materials, i.e., the NBS Spinach (SRM-1570) and the NIES Pepperbush (SRM No. 1), and the results obtained are 548±9 ppm (NBS certified value: 550±20 ppm) and 193±4 ppm, respectively.     

Determination of impurities in nuclear fuel element components by neutron activation analysis

Neutron activation analysis methods for the determination of impurities in zirconium cladding material and uranium oxide are described. Detection limits for the elements Al, Cd, Cr, Co, Cu, Hf, Fe, Mn, Ni, W and U in zirconium are below that required by the ASTM B 352-79 standard. The method has been tested on the NIST SRM 360a Zircaloy-2 from which the elements Na, Mg, Al, Ca, V, Cr, Fe, Co, Ni, Cu, Eu and U have been detected. The values for Cr, Fe, Ni and Cu are compared with the certified values. A method for the pre-irradiation separation of the elements Mg, Na, Al, K, Sc, Ca, V, Mn, Cr, Fe, Co, Cu, Zn, Rb, Zr, Cd, Cs, REE and Hf from uranium has been developed. A neutron activation analysis method for the determination of those elements in uranium is described. The method is tested by the analysis of the IAEA reference sample SR-54/64. The elements Al, Mn, V, Cu, Cr, Co, Ni and Fe have been detected and the results compared with the certified values.     

Dosage de quelques impuretés dans le gallium par activation neutronique

Neutron activation is suggested for the determination of Pt, Au, Hg, Sc, Zn and Sn in high purity gallium. Pt, Hg and Au are reduced to metals, gallium is extracted and then Sc, Zn, and Sn are separated on Dowex 1×8 ion exhanger. All components except Sn are determined by substoichiometric methods in the form of chelate complexes. Sn is extracted with oxine into chloroform, and the chemical yield measured by spectrophotometry.      

An improved metal extraction procedure for the determination of trace metals in sea water by atomic absorption spectrometry with electrothermal atomization

A rapid carbamate extraction method with pyrrolidinedithiocarbamate and diethyldithiocarbamate is described for the simultaneous determination of Cd, Co, Cu, Fe, Ni, Pb and Zn in sea water by atomic absorption spectrometry with a graphite atomizer. The metal—carbamate complexes are extracted from 500 ml of sea water into Freon TF and back-extracted into 10 ml of 0.3 M nitric acid. The method has considerable advantages over previously recommended extraction procedures. The metals are transferred to a solution in which their concentrations do not change with time, and which can be easily stored for transportation. The sensitivity is high enough for analysis of open ocean waters.     

Direct spectrophotometry of silver in a non-aqueous medium

Silver in the range 0.01–10 p.p.m. is extracted from aqueous solution containing anthranilic acid diacetic acid into methyl isobutyl ketone as silver di-n-butylammonium salicylate without interference from 10-fold amounts of Mg, Ca, Zn, Pb, Al, Cu(II), Ni Co(II), Mn(II), Fe(III), Bi or any compatible common anion. Hg(II) is co-extracted slightly but can be retained in the aqueous phase with EDTA. Spectrophotometric determination of the extracted silver is done with pyrogallol red at 390 mμ in 4-cm cuvettes. The colour system is stable and reproducible. No special purification of reagents is necessary even for the lowest concentrations of silver.     

Determination of trace elements in atmospheric wet precipitation by instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) methods have been developed for the simultaneous determination of multielement concentrations in both particulate and soluble fractions of atmospheric wet precipitation (AWP). Samples of AWP collected across Canada by Canadian Network for Sampling Precipitation (CANSAP) have been analyzed. The INAA method involves four sequential irradiations and counting after five different decay periods for measuring Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cu, Dy, Fe, Hf, Hg, I, K, La, Mg, Mn, Na, Rb, Sb, Sc, Se, Sm, Sr, Ti V and Zn. Precision and accuracy of the INAA methods have been evaluated, and detection limits have been calculated.     

Zinc and iron determination in serum and urine samples of thyroid patients using cloud point extraction

A simple and rapid cloud point extraction method was applied for preconcentration of trace quantities of zinc (Zn) and iron (Fe) in biological samples (serum and urine) of thyroid patients prior to determination by flame atomic absorption spectrometry. The metals in serum and urine samples were complexed with 1-(2-thiazolylazo)-2-naphthol and entrapped in the surfactant octylphenoxypolyethoxyethanol (Triton X-114). After centrifugation, the surfactant-rich phase was diluted with 0.1 M HNO3 in methanol. For optimum recovery of analytes, the influences of the analytical parameters, including pH and amounts of complexing and surfactant reagents, were investigated. Enrichment factors of 66.4 and 70.2 were obtained for the preconcentration of Zn(II) and Fe(III), respectively. The obtained results showed sufficient recoveries (>98%) for Zn(II) and Fe(III) in certified reference materials (CRMs). The proposed method was applied to the determination of Zn(II) and Fe(III) in biological (serum and urine) samples and CRMs.