XRF SQX Analysis

Examples of semiquantitative (SQX) XRF analyses are shown below. These examples represent a variety of reference materials prepared using both pressed powders and fused glass disks.

Even thin films of small samples (5-100 mg) can give excellent results as shown in the first example. This sample was a powdered glass mounted as a thin film on top of pressed paraffin.

E-Glass Standard

Thin film on top of paraffin
		Wt. %
	Certified	Observed
SiO₂	54.53	55
CaO	17.43	21
Al₂O₃	14.62	16
MgO	4.67	6.3
Fe₂O₃	0.42	0.55
Na₂O	0.22	0.33
TiO₂	0.23	0.33
ZrO₂	0.12	0.02
Cr₂O₃	0.019	0.014
Date Analyzed:		8-7-2003

Conclusions:

XRF produces excellent Semi-Quantitative (SQX) Results
XRF SQX range is ~0.01%-100%
XRF is for solids while samples for ICP-MS must be dissolved

More Information:

How does XRF SQX work?
What does and XRF scan look like?
Spot Analysis with XRF?
How does XRF SQX compare to an ICPMS Metals Screen ?
Quantitative Analysis by XRF

For a quotation...

In this example, NIST SRM 679 Brick Clay was fused with lithium tetraborate to form a fused glass disk.

Rigaku ZSX100e

Automatic Sample Changer

SRM 679 Brick Clay

Lithiumn tetraborate fusion
		Wt. %
	Certified	Observed
SiO₂	52.03	55
Al₂O₃	20.81	22
Fe₂O₃	12.94	14
K₂O	2.93	3.4
MgO	1.25	1.5
TiO₂	0.962	1.1
Na₂O	0.176	0.66
MnO	0.223	0.39
CaO	0.228	0.33
P₂O₅	0.172	0.18
Cr₂O₃	0.016	0.028
ZnO	0.0187	0.017
SrO	0.0087	0.011
Date Analyzed:		8-27-2003

In these next two examples, the reference materials were mixed with an organic binder and pressed into pellets for analysis.

SRM 77 Bauxite

Pressed powder pellet
		Wt. %
	Certified	Observed
Al₂O₃	59.4	57
SiO₂	32.4	33
TiO₂	2.9	3.2
Fe₂O₃	0.9	2.1
ZrO₂	0.09	0.085
Date Analyzed:		9-30-2003

SRM 88 Dolomite Limestone

Pressed Powder pellet
		Wt. %
	Certified	Observed
CaO	30.5	35
MgO	21.5	27
SiO₂	0.31	0.33
Al₂O₃	0.067	0.26
SO₃	0.05	0.09
Na₂O	0.08	0.045
K₂O	0.03	0.023
MnO	0.006	0.013
P₂O₅	0.003	0.008
SrO	<0.01	0.008
Date Analyzed:		9-30-2003

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