Trace elements detected

Applicable to major, minor and trace elements (detection limits 0.1 ppm)... 

The source of Au was most likely the gold crucible generally used for crystal growing. A comparative analysis of the crystal energy dispersive spectrometry using a SEM (q.v.) identified the primary elements, plus a very weak peak for Au and no indication of Cr and Fe traces. This demonstrates the advantage of PIXE over SEM in terms of sensitivity for trace element detection. 

Because modern instruments are capable of trace element detection in the part per trillion concentration range, laboratories must take extreme care in preventing contamination during sample preparation and instrumental analysis. To monitor the preparation and analysis processes, laboratories use method blanks that are prepared and analyzed together with the samples. The sources of analytical blank and sample contamination and the measures to eliminate them are as follows ... 

Comparison of the levels of some trace elements detected by the non-destructive neutron activation analysis in five tapeworms - parasites of birds. Bulletin de I Academie Polonaise des Sciences (Sciences Biologiques), 25 49-54. 

Table II Trace elements detected in polyethylene film...

B22. Budinger, T. F., Forwell, J. R., Smith, A. R., and Bicknel, M., Human tissue trace element detection by neutron activation without chemical separation. Int. J. Appl. Radial. Isotop. 23, 49-56 (1972). 

Meyer G. A. and Thompson M. D. (1985) Determination of trace element detection limits in air and oxygen inductively coupled plasmas, Spectroehim Acta, Part B 40 195—207. 

It produces a complex line spectrum due mostly to excited neutral atoms. The DC arc is widely used because it can be applied to almost any kind of solid sample and because it exhibits the highest sensitivity for trace element detection. Its lack of stability results in somewhat poor precision. 

In spite of the fact that the total number of essential trace elements detectable by ICP-and or DCP-emission spectrometry is relatively small, this analytical technique has a considerable capacity in this field of application, above all due to the possibility of multielement determinations. 

Details about the preparation and analytical methods applied can be found in the original work cited with each example. Typical uncertainties (2 sigma) are between 2 and 5 rel.% for major elements and between 5 and 10 rel.% for trace elements. Detection limits are given in the appendix directly with the analyses. 

In order to make the circle of trace elements detectable by group extraction as wide as possible, F. A. Pohl has described a method in which the... 

Applications So far, intracavity laser spectroscopy has been applied primarily to the detection of absorption spectra of gaseous impurities such as NH3 and CH4 in the near-infrared region using a tunable broadband laser. Special DLs designed with an external cavity have also been investigated recently for this purpose. CRS has been applied successfully to trace element detection using the ICP as the atomization system. The detection limits observed are at sub-parts per billion level (e.g., 0.3 ng ml for lead) and comparable to the detection limits achieved with ICP-MS. 

In addition to the applications mentioned above, a wide variety of lesser activities in all branches of science are studied using PIXE. In all cases where it is beneficial to use a trace element analytical technique that combines a lateral resolution of 1 pm with trace element detection limits (l-10pgg =10 -10 g), micro-PIXE is an option well worth considering. 

Dobeh, M., Nebiker, E, Suter, M., Synal, H., Vetterli, D. (1994) Accelerator SIMS for trace element detection. Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms, 85,110-11 A. 

An immediate distinction needs to be made between dynamic and static SIMS experiments. In the former, a primary ion current density of typically > 10 pA cm is used and this leads to rapid sputtering of material. The surface is eroded at a rate of order nm s and by following the intensity of chosen peaks in the mass spectrum as a function of time, a concentration depth profile can be constructed. In this mode SIMS can be very sensitive, with trace element detection limits in the ppm-ppb range. However, quantification is not straightforward. Secondary ion intensities are strongly matrix-dependent and extensive calibration procedures involving closely related standards of known composition and under identical experimental conditions must be used to extract quantitative concentrations. 

M. Krachler, J. Zheng, D. Fisher, and W. Shotyk. Analytical procedures for improved trace element detection limits in polar ice from Arctic Canada using ICP-SMS. Analytica Chimica Acta 530 291-298, 2005. 

SSMS Spark Source Mass Spectroscopy Sample in the form of Iwo electrodes High voltage R.F. spark produces ions Ions - analy in mass spectrometer 1-5 in Survey of trace elements detection limit 0 01-0 06 ppm 9... 

For the trace element detection, ICP-AES and GFAAS (ASTM D-6357 [80) are frequently used. 

Figure 2 shows the PIXE spectrum from a single ambient aerosol particle, showing the major and trace elements detected. 

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