XRF Lab
Contact: Tyrone O. Rooney
Department of Geological Sciences
211 Natural Sciences Building
Michigan State University, East Lansing, MI 48824-1115
Phone: (517) 432-5522
Fax: (517) 353-8787
The XRF laboratory at Michigan State University installed a Bruker S4 PIONEER – it is a 4 kW wavelength dispersive X-ray fluorescence spectrometer (WDXRF). It is dedicated primarily to serve the geosciences, but can be used for diverse applications (forensic science, archeology, industrial compounds, etc.). The S4 PIONEER with advanced 4 kW tube provides highest sensitivity especially for light elements and trace elements due to optimized beam geometry and very thin Beryllium XRF tube window used in combination with software optimized excitation parameters for each element analyzed.
Data reduction is performed with Bruker's SPECTRAplus software using fundamental parameters.
Sample preparation
Fused disks
The dissolution of a portion of the sample by a flux and fusion into a homogeneous glass entirely eliminates particle size and mineralogical effects. The fusion technique also has additional advantages:
- high specimen dilution for the purpose of decreasing matrix effects
- ease of preparing standards of desired composition
The fusion procedure consists of heating a mixture of sample and flux at high temperatures (800 to 1200°C) so that the flux melts and the sample dissolves. The overall composition and cooling conditions is such that the end product after cooling is a one-phase glass.
Heating of the sample-flux mixture is done in platinum alloy crucibles, and then poured into a Pt mold. Two fusion methods are used:
1. High dilution fusion (HDF) where 9 grams of LiTetraborate is mixed with 1 gram of powder. This is the preferred method for major-element analyses
2. Low-dilution fusion (LDF) where 9 grams of LiTetraborate is mixed with 4 gram of powder. This method is used when XRF analyses are combined with laser ablation ICP-MS using the same glass disk for the two type of analyses.
Pressed powders
For very low concentrations of trace elements, some XRF analyses are made on pressed powders. These are made with cellulose as a binder in a 3/1 powder to binder ratio.
Evaluation of precision and accuracy of XRF and ICP-MS on glass disks:
JB-1a Treated as an unknown for XRF and ICP-MS analyses. |
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(5 different samples were prepared as glass disks.) |
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Variable |
N |
Mean |
Median |
StDev |
SE** |
Given* |
XRF data |
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SiO2 |
5 |
52.054 |
52.16 |
0.273 |
0.122 |
52.41 |
TiO2 |
5 |
1.282 |
1.28 |
0.0045 |
0.002 |
1.32 |
Al2O3 |
5 |
14.504 |
14.5 |
0.036 |
0.016 |
14.53 |
Fe2O3 |
5 |
8.998 |
9 |
0.0045 |
0.002 |
9.05 |
MnO |
5 |
0.14 |
0.14 |
0 |
0 |
0.15 |
MgO |
5 |
7.824 |
7.81 |
0.0688 |
0.0308 |
7.83 |
CaO |
5 |
9.288 |
9.29 |
0.0084 |
0.0037 |
9.31 |
Na2O |
5 |
2.714 |
2.71 |
0.023 |
0.0103 |
2.73 |
K2O |
5 |
1.382 |
1.38 |
0.0045 |
0.002 |
1.4 |
P2O5 |
5 |
0.268 |
0.27 |
0.00447 |
0.002 |
0.26 |
totals |
5 |
98.454 |
98.49 |
0.171 |
0.076 |
98.99 |
Cr |
5 |
373.42 |
371.7 |
6.09 |
2.72 |
392 |
Ni |
5 |
138.26 |
137.8 |
2.29 |
1.02 |
139 |
Cu |
5 |
74.42 |
74.6 |
5.89 |
2.63 |
57 |
Zn |
5 |
73.68 |
73.6 |
0.701 |
0.314 |
82 |
Rb |
5 |
40.42 |
41 |
1.789 |
0.8 |
39 |
Sr |
5 |
459.76 |
460.1 |
2.16 |
0.96 |
442 |
Y |
5 |
22.86 |
22.5 |
0.966 |
0.432 |
24 |
Zr |
5 |
139.06 |
139 |
0.99 |
0.44 |
144 |
Nb |
5 |
22.22 |
22.2 |
0.74 |
0.331 |
27 |
La |
5 |
27.26 |
29.4 |
5.9 |
2.64 |
38 |
Ba |
5 |
455.06 |
460.6 |
21.63 |
9.67 |
504 |
ICP-MS Data |
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Zr |
5 |
147.13 |
147.33 |
1.97 |
0.88 |
144 |
Ba |
5 |
473.72 |
475.75 |
5.74 |
2.57 |
504 |
La |
5 |
38.24 |
38.32 |
0.48 |
0.22 |
37.6 |
Ce |
5 |
62.63 |
63.16 |
1.25 |
0.56 |
65.9 |
Pr |
5 |
7.29 |
7.39 |
0.25 |
0.11 |
7.3 |
Nd |
5 |
27.36 |
27.57 |
0.82 |
0.36 |
26.9 |
Sm |
5 |
5.47 |
5.52 |
0.20 |
0.09 |
5.07 |
Eu |
5 |
1.54 |
1.55 |
0.07 |
0.03 |
1.46 |
Gd |
5 |
5.08 |
5.13 |
0.14 |
0.06 |
4.67 |
Tb |
5 |
0.79 |
0.8 |
0.02 |
0.01 |
0.69 |
Y |
5 |
24.57 |
24.55 |
0.17 |
0.08 |
24 |
Dy |
5 |
4.25 |
4.28 |
0.09 |
0.04 |
3.99 |
Ho |
5 |
0.83 |
0.84 |
0.03 |
0.01 |
0.71 |
Er |
5 |
2.30 |
2.31 |
0.07 |
0.03 |
2.18 |
Yb |
5 |
2.27 |
2.29 |
0.09 |
0.04 |
2.1 |
Lu |
5 |
0.33 |
0.34 |
0.01 |
0.01 |
0.33 |
V |
5 |
186.88 |
186.39 |
3.49 |
1.56 |
205 |
Cr |
5 |
380.92 |
377.91 |
8.72 |
3.90 |
392 |
Nb |
5 |
27.21 |
26.98 |
0.67 |
0.30 |
26.9 |
Hf |
5 |
3.73 |
3.78 |
0.18 |
0.08 |
6.65 |
Ta |
5 |
1.83 |
1.86 |
0.08 |
0.04 |
1.93 |
Pb |
5 |
5.85 |
5.92 |
0.18 |
0.08 |
6.76 |
Th |
5 |
10.02 |
10.11 |
0.36 |
0.16 |
9.03 |
U |
5 |
1.64 |
1.67 |
0.07 |
0.03 |
1.67 |
* Nimai et al. (1995) Geostandards Newsletter, 19, 135-213 |
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** Standard error = standard deviation divided by the square root of the number of samples |
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Analytical Fees
The joint X-ray Fluorescence and ICP-MS Laboratories at MSU offer a variety of analytical services, including elemental packages for rock and soil samples (Option 1 below).
The following schedule shows estimated fees. Additional discounts may be given for large numbers of samples or in-house sample preparation. Fees are subject to change at any time. Prices reflect a normal turn-around time of about one (1) month. Rush orders may require additional charges. Please consult Tyrone Rooney before officially quoting any prices.
1. Geological (rock and soil) Samples
Sample Preparation: All samples are analyzed as glass disks, prepared by fusion of finely-ground rock powders with lithium tetraborate. Samples may be submitted as powders or in bulk. Submit a minimum of 8 grams powder or 30 grams whole rock. Sample preparation fees for any type of elemental analysis are as follows:
Trimming/powdering of bulk samples |
$5/sample |
Li2B4O7 fusion (of powdered samples*) |
$6.50/sample |
*Submitted sample powders should be fine enough so they are not “gritty” when rubbed between sheets of paper. Re-powdering of gritty samples will require an additional charge.
Users may also request to prepare their own samples at MSU, subject to a $2.00/sample materials charge.
Major and Trace Element Packages (per sample):
Academic Research |
Commercial |
|
Major elements + Rb, Sr, and Zr |
$27 |
$54 |
Major elements + 11 trace elements (XRF) |
$40 |
$80 |
Major elements + 29 trace elements (XRF + LA-ICP-MS)* |
$100 |
$200 |
*A minimum charge of $250 (academic) and $500 (commercial) will apply for all geological analyses involving LA-ICP-MS. This cost reflects the minimum time to tune the instrument, run standards, and data processing.
