A Statistical Comparison of Data Obtained from Pressed Disk and Fused Bead Preparation Techniques for Geological Samples

1981 ◽  
Vol 25 ◽  
pp. 117-120
Author(s):  
Randall H. Dow
Keyword(s):  
Trace Elements ◽  
Matrix Effects ◽  
Fluorescence Analysis ◽  
Lithium Tetraborate ◽  
Geological Samples ◽  
X Ray ◽  
Fundamental Parameters ◽  
Statistical Comparison ◽  
Preparation Techniques ◽  
Ground Powder

AbstractThe analysis of geological samples by x-ray fluorescence analysis is complicated by matrix effects and sample variability. Diluting the sample in a suitable matrix such as lithium tetraborate and then fusing it helps to reduce problems associated with sample inhomogeneities and reduces matrix effects considerably.Unfortunately, many of the trace elements in the sample can be diluted below their detection limits by this technique. Pressing the ground powder into a hard disk avoids this problem and is less time consuming. Matrix effects can be very serious however, but can be calculated and compensated for by fundamental parameters programs.

Slope-Ratio Technique for the Determination of Trace Elements by X-Ray Spectroscopy: A New Approach to Matrix Problems

1968 ◽  
Vol 22 (4) ◽  
pp. 321-324 ◽  
Author(s):  
Frank Cuttitta ◽  
Harry J. Rose
Keyword(s):  
Trace Elements ◽  
Matrix Effects ◽  
Fluorescence Analysis ◽  
Slope Ratio ◽  
New Approach ◽  
X Ray ◽  
Standard Curve ◽  
Residual Matrix ◽  
Matrix Problems

A new approach to solving matrix problems in x-ray fluorescence analysis of trace elements has been applied to the determination of bromine in saline waters and zinc in silicates. The method requires no prior knowledge of the chemical composition of the sample. Marked matrix effects are minimized by dilution, and the problem of variable backgrounds due to residual matrix effects is solved by using a slope-ratio technique. In this proposed technique, the slope of a standard curve prepared from pure solutions is compared with that of spiked samples. The ratio of the slopes of these two curves permits the calculation of an adjusted background which does not significantly differ from that of an absorbent impregnated with the sample matrix free of the element sought. Experimental parameters concerning the technique are presented. The excellent agreement of the zinc and bromine data with analytical results obtained by more conventional methods suggests that the technique can be used for the determination of other trace constituents in geologic materials. Application of the slope-ratio technique to other modes of instrumental analysis appears feasible.

Examples of Analysis from an Integrated X-Ray Fluorescence Analysis System Using NRLXRF

1981 ◽  
Vol 25 ◽  
pp. 81-84
Author(s):  
B. E. Artz ◽  
M. J. Rokosz
Keyword(s):  
Energy Dispersive Spectrometer ◽  
Fluorescence Analysis ◽  
Fundamental Parameter ◽  
Analysis Program ◽  
X Ray ◽  
Fundamental Parameters ◽  
Xrf Analysis ◽  
Parameters Analysis ◽  
Analysis System ◽  
Preparation Techniques

Methods of correction for matrix differences are required in X-ray Fluorescence (XRF) Analysis when the overall composition of the unknowns is substantially different from the available standards. Sample preparation techniques used to minimize matrix differences often require development time and can consume irreplaceable sample material. Alternatively, the increasing computer power available to the analyst and the refinement of computer programs using fundamental parameter calculations has made this approach more attractive.A system-consisting of a Siemens SRS-1 wavelength dispersive spectrometer (WDS), a KEVEX 0810-A/NS880 energy dispersive spectrometer (EDS), software for data collection and manipulation and a 40 element version of the NRLXRF fundamental-parameters analysis program has been put together to simplify XRF analysis of samples lacking standards of a similar composition. This configuration is shown schematically in Figure I.

The Reduction of Matrix Effects in X-Ray Fluorescence Analysis by the Monte Carlo, Fundamental Parameters Method

1978 ◽  
Vol 22 ◽  
pp. 343-356 ◽  
Author(s):  
R. P. Gardner ◽  
J. M. Doster
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Analytical Solutions ◽  
Matrix Effects ◽  
Fluorescence Analysis ◽  
X Ray ◽  
Fundamental Parameters ◽  
The Monte Carlo Method ◽  
Average Angle

A review of the application of the Monte Carlo, fundamental parameters method to XRF fluorescence analysis for the reduction of matrix effects is made. The analytical solutions arising from theoretical equations are given along with the restrictive assumptions that are necessary to this approach. The extensions of the fundamental parameters method by the Monte Carlo simulation to practical situations that require much less restrictive assumptions are outlined. The average angle approach to the use of the analytical solutions is investigated by comparison with the Monte Carlo method. Future extensions of the fundamental parameters method by the Monte Carlo approach are discussed.

XRMF applications of a monolithic, polycapillary, focusing x-ray optic

1996 ◽  
Vol 54 ◽  
pp. 240-241
Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla
Keyword(s):  
Trace Elements ◽  
Point Source ◽  
Focal Spot ◽  
Fluorescence Analysis ◽  
X Rays ◽  
Focal Distance ◽  
Spot Diameter ◽  
X Ray ◽  
Focal Spot Diameter

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.

Sorption of Se (IV) from aqueous solutions with subsequent determination by X-ray fluorescence analysis

2020 ◽  
Vol 86 (10) ◽  
pp. 5-9
Author(s):  
D. G. Filatova ◽  
A. A. Arkhipenko ◽  
M. A. Statkus ◽  
V. V. Es’kina ◽  
V. B. Baranovskaya ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Fluorescence Analysis ◽  
Standard Samples ◽  
Phase Contact Time ◽  
Sorbent Phase ◽  
X Ray ◽  
Fundamental Parameters ◽  
Inductively Coupled ◽  
Subsequent Determination

An approach to sorptive separation of Se (IV) from solutions on a novel S,N-containing sorbent with subsequent determination of the analyte in the sorbent phase by micro-x-ray fluorescence method is presented. The sorbent copolymethylenesulfide-N-alkyl-methylenamine (CMA) was synthesized using «snake in the cage» procedure and proven to be stable in acid solutions. Conditions for quantitative extraction of Se (IV) were determined: sorption in 5 M HCl or 0.05 M HNO3 solutions when heated to 60°C, phase contact time being 1 h. The residual selenium content in the solution was determined by inductively coupled plasma mass spectrometry (ICP-MS) using 82Se isotope. The absence of selenium losses is proved and the mechanism of sorption interaction under specified conditions is proposed. The method of micro-x-ray fluorescence analysis (micro-RFA) with mapping revealed a uniform distribution of selenium on the sorbent surface. The possibility of determining selenium in the sorbent phase by micro-RFA is shown. When comparing the obtained results with the results of calculations by the method of fundamental parameters, it is shown the necessity of using standard samples of sorbates to obtain correct results of RFA determination of selenium in the sorbent phase.

Control of trace elements content in solid-phase extraction sorbent by x-ray fluorescence analysis

2020 ◽  
Author(s):  
E. V. Kochergina ◽  
A. O. Vagina ◽  
A. O. Taukin ◽  
A. V. Abramov ◽  
G. M. Bunkov ◽  
...  
Keyword(s):  
Trace Elements ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Fluorescence Analysis ◽  
Phase Extraction ◽  
X Ray
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