Quantitative Determination Of Elements Research Articles

Evaluation of analytical uncertainty in quantitative determination of elements - The case of boron

BackgroundThe uncertainty including accuracy and precision is the most vital factor that determines the overall quality of quantitative analysis. The uncertainty has been, however, evaluated relatively within the same analytical technique. Given this background, the present study evaluates the uncertainty on quantitative elemental analysis with a quasi-absolute approach. The objectives of this study are (1) to investigate the analytical uncertainty of prompt gamma-ray analysis (PGA), a chemical interference-free method in principle, on the quantitative analysis of boron and (2) to evaluate the applicability of inductively coupled plasma optical emission spectrometry (ICP-OES), a common technique for quantitative elemental analysis including boron. ResultsPGA provided analytical quantity that is equivalent to the true quantity. The quantity values determined for a series of boron-containing samples are all well above the detection limit of the PGA system, the quantity resolution of which is also much smaller than the minimum difference in quantity among the samples. These facts confirm that the evaluation of analytical uncertainty with the present PGA system is statistically meaningful. The analytical uncertainty in both methods was adequately evaluated by comparing the results from PGA and ICP-OES for a series of boron-containing materials with different physical/chemical properties (i.e. CrB2, B4C, and solidified products of stainless steel-B4C melt) and the major sources of uncertainty in both methods are specified. The conditions for sample preparation/pretreatment were optimized to lower the uncertainty. Significance and noveltyThis study proposes a new concept to perform the quasi-absolute evaluation of analytical uncertainty by employing a chemical interference-free technique. The proposed concept is not limited to the combination of PGA and ICP-OES as demonstrated in this study, but it is applicable to any combination of any analytical methods for any element. Hence, the concept demonstrated in this study could be beneficial to a wide range of analytical chemistry.

ИЗУЧЕНИЕ РАКОВИННОГО ВЕЩЕСТВА СОВРЕМЕННЫХ И ПЛЕЙСТОЦЕНОВЫХ МОЛЛЮСКОВ РОДА DIDACNA

One of the ways to study the reactions of marine invertebrates to the external effects of changes in temperature and salinity is the biogeochemical analysis of skeletal parts, which are consistently built up during ontogenesis and record a variety of information about these changes. The most studied shells of mollusks, sea urchin shells and skeletal parts of corals. Information about the chemical composition of modern and fossil mollusk shells is widely used in solving geological and biological problems, including determining the temperature and salinity of ancient marine basins, studying the diagenesis of carbonate sediments, and the biochemical evolution of invertebrates. X-ray diffraction analysis of the shell matter of didacnae belonging to the Cardiidae showed an aragonite composition. The quantitative determination of elements in mollusk shells by microprobe analysis of spot scanning and spectrometric method is carried out. Samples were taken in successive layers of shell growth within the annual ring, and the seasonal dynamics of strontium changes were detected. For Didacna, strontium is the main element-indicator of seasonal and ontogenetic growth, is included in the crystal lattice of aragonite and forms strong compounds in the process of shell formation during the life of these bivalves. The variability of seasonal, ontogenetic, and taxonomic differences in a number of indicator elements in living and Pleistocene bivalves of the genus Didacna was studied.

Accuracy improvement in XRF analysis for the quantification of elements ranging from tenths to thousands μg g−1 in human tissues using different matrix reference materials

In this work, we aim at achieving the most accurate quantitative determination of elements in human tissues by means of X-ray fluorescence spectrometry using the external calibration approach.

Quantitative Determination of Elements in Soymida Febrifuga Medicinal Plant by Using PIXE and ICP-MS Techniques

Quantitative Determination of Elements in Soymida Febrifuga Medicinal Plant by Using PIXE and ICP-MS Techniques

Laboratory total reflection X-ray fluorescence analysis for low concentration samples

Quantitative elemental determination for concentrations in the ppb range requires a careful preparation of the sample. In particular, for elemental analysis of very low concentration samples, less than 1ng/mm2, a very bright X-ray source, typically synchrotron radiation (SR) in total external reflection fluorescence regime (SR-TXRF), is required. Here, we wish to demonstrate that a conventional source combined with a polycapillary semi-lens can provide a quasi-parallel beam intense enough for desktop TXRF analysis of low concentration samples.

Imaging of metals and metal-containing species in biological tissues and on gels by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS): A new analytical strategy for applications in life sciences

Abstract Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has become established as a very efficient and sensitive trace, ultratrace, and surface analytical technique in the life sciences. We have developed a new analytical imaging technique using LA-ICP-MS to study element distribution in biological tissues. Nowadays, LA imaging ICP-MS using double-focusing sector field (LA-ICP-SFMS) or quadrupole-based mass spectrometers (LA-ICP-QMS) can be applied as an exciting tool providing new information on the pathophysiology, pharmacology, and toxicology of elements of interest in biological systems. The quantitative determination of elements (e.g., Cu, Fe, Zn, Se, and others) in biological tissues is of growing interest especially in brain research (e.g., for studying neurodegenerative diseases such as Alzheimer's or Parkinson's disease). LA-ICP-SFMS was employed to produce images of detailed regionally specific element distributions in thin tissue sections of different sizes (such as control human or rat brain tissues or tumor regions). In addition, imaging MS using LA-ICP-QMS was applied to study the uptake and transport of nutrient and toxic elements in plant tissues. Besides the quantitative imaging of essential and toxic elements in tissues, powerful analytical techniques are also required for the determination and characterization of phosphoproteins and metal-containing proteins within a large pool of proteins, after electrophoretic separation (e.g., blue native, BN and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, SDS-PAGE) into 1D and 2D gels. LA-ICP-MS was used to detect metalloproteins in protein bands of 1D gels or protein spots separated after 2D gel electrophoresis (2D-GE). In addition to elemental determination by LA-ICP-MS, matrix-assisted laser desorption/ionization (MALDI)-MS was employed to identify metal-containing proteins. Recent progress will be discussed in applying LA-ICP-MS in the life sciences, including the imaging of thin slices of tissue and applications in proteome analysis in combination with MALDI-MS to investigate phosphoproteins and metal-containing proteins.

A comparison of SEM-EDS with ICP-AES for the quantitative elemental determination of estuarine particles

Suspended particulate matter (SPM) is a key component regulating the biogeochemistry of natural and contaminant moieties in estuaries. Individual particle analyses can complement conventional bulk analyses of SPM, but are rarely undertaken. This study used scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS) of particles to quantify a range of elements in the reference estuarine sediment PACS-2. This approach was compared with a bulk SPM analysis based on inductively coupled plasma-atomic emission spectrometry (ICP-AES). The median concentrations of Al, Fe, Mg, and Ca for the two approaches were similar, and accuracy for both methods was good. SEM-EDS analysis was also satisfactory for K. Agreement was poorer for Mn and Ti, which were present at trace concentrations. Increasing the number of particles examined by SEM-EDS should improve the analysis. SEM-EDS analysis of SPM from the Tamar Estuary, UK, revealed marked geochemical differences between particle sub-populations.

Development and Evaluation of a Standard Method for the Quantitative Determination of Elements in Float Glass Samples by LA-ICP-MS

Forensic analysis of glass samples was performed in different laboratories within the NITE-CRIME (Natural Isotopes and Trace Elements in Criminalistics and Environmental Forensics) European Network, using a variety of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) systems. The main objective of the interlaboratory tests was to cross-validate the different combinations of laser ablation systems with different ICP-MS instruments. A first study using widely available samples, such as the NIST SRM 610 and NIST SRM 612 reference glasses, led to deviations in the determined concentrations for trace elements amongst the laboratories up to 60%. Extensive discussion among the laboratories and the production of new glass reference standards (FGS 1 and FGS 2) established an improved analytical protocol, which was tested on a well-characterized float glass sample (FG 10-1 from the BKA Wiesbaden collection). Subsequently, interlaboratory tests produced improved results for nearly all elements with a deviation of < 10%, demonstrating that LA-ICP-MS can deliver absolute quantitative measurements on major, minor and trace elements in float glass samples for forensic and other purposes.

Quantitative elemental determination in water and oil by laser induced breakdown spectroscopy

Laser induced breakdown spectroscopy has been used to evaluate the potentiality of the technique for the determination of trace amounts of elements in different types of liquids, in the framework of nuclear applications. A specific set-up using a pulsed laser focussed with a tilted angle on the surface of the liquid is presented. It allows on-line quantitative measurements with good reliability and reproducibility. Twelve elements (Pb, Si, Ca, Na, Zn, Sn, Al, Cu, Ni, Fe, Mg, Cr) have been studied in two different liquid matrices: water and oil. Detection limits (0.3–120 μg ml −1) and reproducibilities (ca. 3%) are reported. Moreover, the use of an echelle spectrometer for such elemental analysis is also proposed.

Cleaning of ultrafiltration membranes after treatment of oily waste water

The influences of different types of cleaning agents on a polysulphone ultrafiltration (UF) membrane which had been used to treat oily waste water were investigated. The cleaning experiments were performed with samples of polysulphone membranes removed from a commercial plant in which oily waste water is treated. Five different cleaning agents were and their influences on the fluxes were investigated. The influence on the flux when cleaning with the different cleaning agents in succession was also studied. Deposits on the membrane surface, before and after cleaning, were analysed using different methods. Most of the analyses were carried out using scanning electron microscopy (SEM) in combination with energy dispersive X-ray (EDX) combined with a micro-analysis system permitting quantitative determination of elements. Some analyses were also performed using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS).

Some applications of the fundamental parameter method in energy‐dispersive x‐ray fluorescence analysis by isotope excitation

AbstractThree iteration processes were developed for the quantitative determination of elements in solid samples. The methods used are based on a model expressing the relationship between the concentration and the characteristic intensity. The methods were checked by the analysis of steels, aluminium alloys, metallic glasses and organic samples.

Constancy in Elemental Composition of Identical and Symmetrical Ceramic Pairs

Recently much work has been done on Chinese porcelains with the use of the EDXRF technique; the results have been encouraging. In general, quantitative elemental determination requires tedious calibration procedures. In this study, we shall use a simplified, rapid EDXRF method to obtain quantitative values of trace elements of rubidium, strontium, yttrium, zirconium, and niobium. Briefly, the method makes use of the calibration curve on a plot of ln[intensity (cps)/concentration (%)] vs. ln[energy (keV)] for the elements Rb to Nb. Using such a calibration curve, we were able to obtain quantitative values of the concentration of the element by simply measuring its intensity under the same geometrical conditions.

A Rapid EDXRF Method of Simultaneous Quantitative Elemental Analysis Using an Annular Cd-109 Source

Recent EDXRF studies of Chinese ceramics of the Ming (1368–1644) and Qing (1644–1911) dynasties, the Republic period (1912–1939), and the modern period (after World War II) have given encouraging results for the identification of modern fake reproductions and the attribution and dating of Chinese porcelains. However, quantitative elemental determination requires tedious calibration procedures. In general, a separate calibration curve is required for each element to be determined, and, when one is using Cd-109 sources, quantitative elemental determination (say from Mn to Nb) would be rather time-consuming.

Analysis of oil with inductively coupled plasma: total process automation

This paper describes a new device designed to automate the quantitative determination of elements in a variety of oil types using inductively coupled plasma atomic emission spectrometry. This Automatic Injection and Dilution System 1 1 Patent approved. allows the delivery of a uniform and highly reproducible diluted sample to the plasma. Since dilution is automatic and coincident with sample uptake, throughput rates of 80 samples per h can be routinely achieved. Instrument parameters and construction of the device are detailed. Errors due to viscosity variations over a 5–22 cSt (210°F) range are shown to be negligible. Utilizing this technique, the determination of trace elements in lubricating oils has an overall precision of 2–5 % at the 95 % confidence level.

Quantitative determination of elements by energy dispersive X‐ray microanalysis and atomic absorption spectrometry in egg cells of Lymnaea stagnalis

SUMMARYMagnesium, phosphorus, potassium, calcium and iron in Lymnaea stagnalis egg cells at the four cell embryonic stage were quantitatively analysed by energy dispersive X‐ray analysis. The accuracy of the results was confirmed by atomic absorption spectroscopy using the graphite tube atomizer. It is shown that at 20 kV acceleration voltage the Hall equation can be applied in X‐ray microanalysis of air‐dried biological specimens of up to 8 μm thickness when calibration standards of nearly the same thickness and elemental composition are used.In the past few years considerable effort has been devoted to the X‐ray microanalysis of cells and subcellular structures in tissues. Special interest went to the determination of local concentrations of low atomic weight elements in the cells (Gupta et al., 1978). These elements partly occur in the form of mobile ions and their concentration distribution is easily disturbed by preparative procedures. Only cryogenic methods, like freeze‐sectioning (Echlin &amp; Moreton, 1974) and freeze‐fracturing (Zs‐Nagy et al., 1977) are able to meet these problems of preparation.With single cells, e.g. invertebrate egg cells or amoebae, the situation is somewhat less complicated because these cells can be handled individually. A number of problems in cell biology, e.g. ion movement during the cell cycle, may be solved by analysis of the ion content of whole cells. Dried down Lymnaea egg cells at SEM accelerating voltages can be considered as semi‐thick specimens in which the local mass per unit area will show some variation. In order to convert X‐ray data from these specimens to concentrations, semi‐thick calibration standards should be prepared with essentially the same matrix composition as the biological material. Under such circumstances the equation

Limits of elemental chemical analysis with small samples

Chemical methods of analysis, especially titrimetric and photometric, lend themselves to the accurate quantitative determination of elements in small samples of their compounds. Even today these methods still have their place beside the more modern “instrumental” methods. Several orders of magnitude exist between the statistically-calculated smallest sample that can be used with the microchemical method and that used in practice to obtain accurate results. There are several reasons for this difference, which are discussed. Errors arising in the grinding and weighing of the sample, chemical separation stages and in the method of determination are discussed, and examples with organic and inorganic materials given.The lower limit of determination by classical micro-analytical methods has been lowered by adjusting the solution concentrations and techniques of trace analysis usually used. It was shown that in some specific cases this approach enabled a quantitative determination of the element in samples of a few micrograms to be made with a precision of about 1 per cent.Further work is reported in which fluorimetric and gas-chromatographic techniques are used for determining elements present in nanogram amounts.

A new method for analysis in low concentrations using radioisotopes in polarography

By collecting the mercury drops from a special polarographic cell at each potential and measuring the radioactivity of the drops, a radioactivity-potential curve similar to that of I vs. V is obtained with radioactive elements reduced to the zero-oxidation state. The radioactivity measurement is much more sensitive than the measurement of the diffusion current and can be used for qualitative and quantitative determination of elements at lower concentrations than with conventional polarography. Non-radioactive elements can also be detected by making use of a radioactive element with a less negative half-wave potential, due to the oxidation-reduction replacement on the mercury drops of the non-radioactive by the radioactive element.

Absorption Effects in X-Ray Fluorescence Measurement of Elements in Oil

AbstractThe influence of absorption effects in measuring elements in petroleum oil by X-ray fluorescence can, under certain circumstances, be predicted approximately from theory. Exact information on specific systems and instrumental conditions must practically be provided by experiment, however. The influence of absorption on fluorescent intensity under specific conditions of interest has been studied from three viewpoints; varying the depth through oil of a solid elemental specimen, varying the depth of a solution containing the element dissolved in oil, and varying the amount of the dissolved element in oil over a broad range in concentration. The group of elements selected for study illustrate characteristic fluorescent radiations often1 measured from oil. The experimental results are expressed graphically and are compared between elements as well as with theory. The results have analytical implications which pertain to the quantitative determination of elements in oil by X-ray fluorescence.

Quantitative Microchemical and Histochemical Analysis of Elements by X-rays

A METHOD of X-ray absorption analysis has been developed which permits the quantitative determination of elements with low atomic numbers in extremely small quantities of a biological tissue. It is based upon the measurement of the absorption of monochromatic X-ray radiation, within a very small area of an object, for example, a microscopic section of a tissue. The measuring procedure, either ionometrically or photographic-photometrically, is repeated in a series of wave-lengths lying on each side of a long-wave X-ray absorption edge of the element sought for. From these experimental data the quantity of the element in question can be calculated. Localization of the area in the specimen to be analysed is secured by taking monochromatic X-ray radio-micrographs. The method permits of the determination in a tissue of elements of atomic number above 6. Thus with the exception of hydrogen, all elements of biological interest can be determined. Analysis may be made upon a volume of tissue corresponding to that of a mammalian cell. In analyses of calcium and phosphorus in biological material, quantities of 10â 10–10â 11 gm. have been determined by the method with an error of 10 per cent.

Mutual Interference in the Microchemical Determination of Ore Minerals

The use of microchemical methods is spreading rapidly, both for the qualitative and quantitative determination of elements. Microchemistry offers a decided advantage over bulk methods, not only because of the greater speed with which the determinations can be carried out, but also because of the very small amounts of material required for a test. Microchemical methods are particularly valuable in determining the composition of the small inclusions in ores and metallurgical products. Most of the reagents used are sufficiently sensitive to show the presence of 0.005 per cent or less of the desired element. Needless to say, if such minute quantities of an element are to be identified, it is essential that the procedure of the test be carefully followed and the utmost caution taken that there is no pollution of the reagent or the test drop. Despite such care, it frequently happens that the test obtained is not wholly satisfactory. Either the color of the precipitate is unusual, the form is changed or entirely different, or sometimes no test is obtained when previous observations have indicated that the element should be present. When such changes occur-and they occur frequently, even in the hands of skilled technicians-the observer is never certain whether they are due to variations in the PH of the solution, concentration of reagent or solution, or to the presence of some interfering anion or cation. The first two variables can be controlled by proper attention to the procedure of the test; in many cases the last variable-presence of an interfering anion or cation-is beyond control. Often, much time could be saved by recognizing that a given variation in the precipitate is caused by the presence of another element. In fact, some of the interferences are as characteristic of the interfering element as any other known test. The presence of a variety of elements in the test drop is due either to a poor sample or to a complex mineral. A poor sample is obtained if the original area of the mineral or inclusion is too small. In this case, allowance can usually be made for the presence in the solution of elements of the host mineral, although their presence may cause notable interferences. Where the mineral varies in composition there may be no hint of the presence of elements, other than those expected in the mineral, until trouble is encountered in the testing.