Spectrographic Determination Research Articles

Atomic emission spectrographic determination of trace elements in environmental objects using a two-jet argon arc plasmatron

The effect of the main components (K, Na, Ca, Mg, Fe) on the atomic and ionic emission of trace elements Sr, Lu, V, Sc, Ti, Cr, Pb, Sn, Ni, Co, Bi, Mn, Pd, Zn, Be, Ba, Zr, Y, and La in atomic emission spectrometry with a two-jet argon arc plasmatron was studied to improve the accuracy of the quantitative multielement analysis of natural objects. It was shown that all of the studied macro elements to a certain extent enhance the analytical signal. The maximum enhancement was 2.5-fold. The effect of the matrix composition of the material is not strong and can easily be controlled by properly selecting the operational conditions of the formation of a plasma jet and bufferation, and also samples and reference elements. It was shown that a wide spectrum of trace elements can be quantitatively determined in various rocks, soils, and plant ashes with a relative standard deviation of 6–15% and detection limit of n × 10−4 to n × 10−6% using unified reference samples prepared synthetically.

The model representation of electrolyte solutions with two-component solvents and mass spectrographic determination of enthalpy change at solvation of Na +Et m(H 2O) n ion clusters by ethanol molecules in water–ethanol solvent

Considering liquid as a set of potential wells (Frenkel's conception), the experimental distribution of sodium ions with respect to a degree of solvation with water and ethanol molecules in water–ethanol solvent can be satisfactorily described by a polynomial ( p a + p b + q) k ( p a and p b are the probabilities of occupancy of one of the k equivalent potential wells near the ion by a water or an ethanol molecule, respectively; q=1− p a − p b ). Basing on the mass spectrographic data, it is shown that values of enthalpy changes, ΔH m, m+ f , for 50 reactions of solvation of ion clusters Na +Et m (H 2O) n with f ethanol molecules in solution ( f=1,2,…,5) are satisfactorily described by the dependence (− ΔH)= C( n, f)exp[− α( n) m] for most reactions.

Spectrographic determination of gold in geological materials after preconcentration on Spheron-Thiol

A spectrographic method for the determination of gold in geological materials after preconcentration on chelating sorbent Spheron-Thiol has been developed. The method involves the decomposition of the samples, preconcentration of Au on Spheron-Thiol, decomposition of the sorbent and spectrographic determination of gold at 267.59 nm. The method is simple, rapid and enables the determination of gold at μg g −1 levels in various types of geological materials with good precision and accuracy. The detection limit is 0.5 μg Au kg −1. The method has been applied to the determination of Au in a number of certified and other reference materials with accurate results.

Spectrographic determination of impurities in an yttrium-barium-copper-oxygen-system high-temperature superconducting ceramic

Spectrographic determination of impurities in an yttrium-barium-copper-oxygen-system high-temperature superconducting ceramic

Wall-stabilised plasma arc applied to the determination of rare earth elements in phosphate samples

A wall-stabilised plasma arc seeded with potassium chloride has been used as an excitation source for the spectrographic determination of rare earth elements in samples of phosphate deposits. The samples were treated with a mixture of HNO3 and HF in a Teflon decomposition vessel and then with H2SO4. The effect of the sample matrix on the excitation temperatures in the plasma and on the analytical curves obtained was studied. The results from the analysis of 12 samples, collected from the Abu Tartur plateau, Western Desert, Egypt, are given. The normalised rare earth patterns reveal a marine environment for deposition.

Spectrographic determination of nitrogen content in petroleum coke

Determinations were made according to the band of cyanogen formed by reaction of carbon with nitrogen in the zone of an ac arc. Spectra were recorded on an ISP-51 spectrograph with a three-lens system of slit illumination. The accuracy of the determination was influenced by the presence of atmospheric nitrogen in the discharge zone and the presence of adsorbed nitrogen in the graphite electrodes, and the samples. The absence of any nitrogen loss in preburning the electrodes was confirmed by data presented in a table. Calibration curves were plotted for raw and calcined coke samples from different sources; results are presented, obtained by the proposed method on raw cokes and compared with results obtained by the Kjeldahl method.

Determination of nickel in asphaltite ash by ultraviolet-visible spectrophotometry and direct current arc emission spectrography

The nickel content of Turkish asphaltite ash was determined and the conditions for the spectrophotometric and spectrographic determination of nickel were investigated. The spectrophotometric determination was performed by measuring the absorbance of the nickel-dimethylglyoxime complex in chloroform. The method was applied to the determination of nickel in standard rock samples containing 6.0 µg ml–1 Ni with a relative error of 1.7%. For the spectrographic determination tetramethylammonium iodide was used as a spectral buffer. The nickel content of asphaltite ash was found to be 0.44% with both methods.

Emission spectrographic determination of volatile trace elements in geologic materials by a carrier distillation technique

Trace levels of chalcophile elements that form volatile sulfide minerals are determined in stream sediments and in the nonmagnetic fraction of a heavy-mineral concentrate of stream sediments by a carrier distillation emission spectrographic method. Photographically recorded spectra of samples are visually compared with those of synthetic standards for the two sample types. Rock and soil samples may also be analyzed by comparison with the stream-sediment standards. A gallium oxide spectrochemical carrier/buffer enhances the early emission of the volatile elements. Detection limits in parts per million attained are: Sb 5, As 20, Bi 0.1, Cd 1, Cu 1, Pb 2, Ag 0.1, Zn 2, and Sn 0.1. A comparison with other methods of analysis, total-burn emission and atomic absorption spectroscopy, shows good correlation for standard reference for materials and samples from a variety of geologic terranes.

Spectrographic determination of zinc in the tissues of adenoma and carcinoma of the prostate.

The authors describe a spectrographic method for the determination of zinc in solid matter. This method may be used to determine semiquantitatively the zinc-content of prostatic tissue. It has been found by this method that the ash from neoplastic prostatic tissue contained less zinc than that from adenomatous prostatic tissue.

Use of fluoridation in spectrographic determination of titanium in corundum single crystals and in the raw material

Use of fluoridation in spectrographic determination of titanium in corundum single crystals and in the raw material

Spectrographic determination of trace elements in solar-grade silicon

An optical emission spectrographic method is described for the estimation of fourteen trace metallic impurities such as B, Pb, Sn etc., in solar-grade silicon. The silicon is ground under liquid nitrogen, then mixed with high-purity graphite powder and sodium fluoride (the latter to improve the line-to-background ratio). The mixture is excited in a d. c. arc (12 A) in a nitrogen atmosphere. The spectra of the sample and standards over the wavelength region 2400–3350 A are photographed. The detection limits for the various elements range from 1 to 25 ppm. A matrix line of silicon is chosen as the internal standard. The mean coefficient of variation in the determination of the various elements is between 9 and 24%.

Spectrographic Determination of Common Impurity Elements in High-Purity Lanthanum Oxide

An emission spectrographic method for the quantitative determination of 17 trace elements in high-purity lanthanum oxide has been developed. The sample was ignited in muffle furnace at 850° for one hour to remove the moisture and carbon dioxide, then blended with equal amount of graphite and 10 mgs of this mixture was taken into electrodes. A 10 amps dc are was employed to excite the mixture and a 3.4 meter Ebert Spectrograph with 15,000 LPI plane grating was used to record the spectrum in the region 2,200 at 3,400 Å. The weak line of lanthanum was used as an internal standard. The working ranges of these elements were: Ag, Mg 0.5 to 50 ppm; Be 0.5 to 100 ppm; V, Cr 1 to 100 ppm; Cu, Sn, Fe 3 to 100 ppm; Ge, Mn, Ni 5 to 100 ppm; B, Co, Pb, Sb 10 to 100 ppm; Ca and Si 30 to 500 ppm. The precisions fell in the range of 10 to 24%. Samples obtained from Engineering Research Laboratory (ERL) of Institute of Nuclear Energy Research were also examined.

Interference of impurities of magnesium oxide matrix in the spectrographic determination of manganese

The influence of trace impurities of MgO matrix on the spectrographic determination of manganese has been investigated. From among 7 metals (Ca, Fe, Co, Ag, Pb, Cu, Ni) only the interferences caused by calcium and nickel in concentrations > 10 ppm proved to be significant. In order to eliminate these interferences their mathematical polynomial models of the second degree have been recommended. Though not wholly adequate, these models permit greater accuracy of analysis than conventional calibration methods.

Spectrographic determination of traces of B, Be, Cd, Si and Co in U3O8 by the d.c. arc cathode-region method

The cathode region of the d.c. arc emission of U3O8 has been photographed (0.6 mm below the cathode) from 2,200 to 3,400 A, using Scribner-Mullin carrier distillation electrodes. Along with the elemental spectra of trace impurities in U3O8, a well resolved Mulliken band (1Σ u + → 1Σ g + ) of the C2 molecule has been observed in the 2,300 A region and its intensity has been found to follow the excitation conditions of the arc. Using some of the well resolved rotational lines in the Mulliken band of C2 molecule as internal standard lines, the trace impurities with analytical lines in 2,200 –2,500 A region (B, Be, Cd, Si and Co) have been satisfactorily determined. This method offers several advantages compared to the well established “carrier distillation” and also the “cathode region” method described by Avni as it has a “built-in” internal standard.

Lowering of the detection limit in spectrographic determination of traces of organic substances

Lowering of the detection limit in spectrographic determination of traces of organic substances

A New Carrier for Direct Spectrographic Determination of Trace Alkalies and Alkaline Earths in High Purity Thorium Oxide

Abstract A d.c. arc emission spectrographic method is described for the determination of sub ppm levels of Ba, Li and Sr and ppm levels of Cs, K and Na in high purity thorium oxide. The method which employs RbCl as carrier is simple and rapid and does not involve the use of any special atmosphere for exciting the sample. It was observed that RbCl shows definite improvement over AgCl in carrier action. The carrier distillation technique reported makes possible the following range of estimations: Li: 0.02 – 5.0 ppm, Ba, Sr: 0.5 – 20 ppm, Cs: 2–50 ppm, K,Na: 5–100 ppm. The detection limit obtained by this method for Li and Sr is lower than that obtained by the earlier carrier-distillation methods reported as well as other direct sensitive techniques of Zeidel and Avni for the analysis of Tho2. The precision of the method ranges from 8% for Cs to 17% for Ba. Volatilization studies on the choice of carrier material are presented.

Spectrographic determination of carbon in powdered samples

Spectrographic determination of carbon in powdered samples

The Emission Spectrographic Determination of Boron in Silicate Materials

A procedure is described for the spectrographic determination of boron in silicate materials such as soils and coal ash. The method is based on the use of a lithium fluoride-graphite buffer with germanium as internal standard. A correction for SiO band interference is made. Standardization is facilitated using boron-in-graphite standards. The precision of the method is ±10% and the accuracy is better than 15%. The limit of detection is 10 μg g−1.

Emission spectrographic determination of trace elements in atmospheric particulate matter

Air containing particulate material was passed continuously for one month through a low-volume air sampler equipped with a cyclone to exclude particulates greater than 10 μm in diameter. The samples and filters were ashed in a low-temperature plasma and, after addition of In 2O 3 support, palladium internal standard and graphite buffer, the ashes were analyzed by a.c. are emission spectrometry. Standard samples were prepared from a commercial standard containing 49 elements. The procedure allows the determination of 14 trace metals (Ag, Al, Cr, Cu, Fe, Ga, Mn, Mo, Ni, Pb, Sn, Ti, V, Zn) with relative standard deviations of 1.4–15.1%. The procedure has been applied successfully to monthly determinations of the average atmospheric concentrations of these elements in Kobe City for the past three years.

Direct emission spectrographic determination of fluoride in geological materials by formation and excitation of calcium fluoride in a direct current arc

Direct emission spectrographic determination of fluoride in geological materials by formation and excitation of calcium fluoride in a direct current arc