New Sapphire Discs S2 PICOFOX Sapphire Sample Carriers

New
Sapphire
Discs
S2 PICOFOX Sapphire Sample Carriers
Sensitive Detection of Silicon
The most common sample carriers for
Total Reflection X-ray Fluorescence
(TXRF) analysis are quartz discs (order no.
B-A20V09). However, due to the silicon
(Si) peak caused by this carrier material the
detection of Si is almost impossible. On
the other hand, Si-free disc materials like
polyacrylics show a significant scattering
background which leads to unsatisfactory
detection limits for certain applications.
LLD and background counts for Si using different carrier materials
Now, sample carriers made of sapphire
are available at Bruker Nano (order no.
B-A20V21). In combination with TXRF these
sample discs enable a fast, straightforward
method for sub-ppm detection of Si.
In the following, different carrier materials
are compared and the application of the
highly polished sapphire discs for water and
pharmaceutical samples is briefly described.
Fig. 1: Comparison of LLD (dark blue) and background counts (light blue) for Si
measurements using different types of sample discs for TXRF.
Comparison of different sample carrier materials
for TXRF
TXRF spectra of a Si washout solution
An aqueous solution containing an internal standard of 1 mg/L
gallium (Ga) was spiked with 100 mg/L Si. 10 µl of this solution was
prepared on four different types of carriers: quartz glass, acrylic
glass, sapphire and glassy carbon. In each case the sample was
measured with the TXRF spectrometer S2 PICOFOX for 1000 s
at 50 kV, 600 µA. Figure 1 shows the background intensities and
the lower limit of detection (LLD) for each carrier type. It clearly
demonstrates the strong correlation between background and
LLD, whereas the sapphire disc provides with about 102 µg/L the
best LLD for Si. It is about four times lower compared to an acrylic
glass disc.
Detection of Si washout during pharmaceutical
production
Peristaltic pumps with Si tubes are commonly used in
pharmaceutical production processes, whereby the washout of Si
is a critical parameter to be controlled regularly. In an experiment
the internal standard scandium (Sc, 10 mg/L) was added to a
typical washout solution and was measured with the S2 PICOFOX
at 50 kV, 600 µA. Figure 2 shows the spectrum of the washout
solution with a clearly visible Si peak. The Si concentration was
calculated to be 670 µg/L and the LLD to be 120 µg/L.
Fig. 2: Spectra of a Si tube washout measurement
after preparation on a sapphire sample disc.
Sapphire sample carriers, polished discs
Dimensions
Diameter: 30 mm, height: 3 mm
Order no.
B-A20V21
Scope of delivery
Set of 25 pieces
Cleaning
RBS 50 / 10 % HNO3 (same cleaning as for quartz discs)
Lifetime
No limitation
Note
Due to small impurities in naturally grown sapphire, these discs are not
suitable for detecting specific elements at low µg/kg levels
More information required ?
Please contact us or find your local partner at www.bruker.com
Bruker Nano GmbH
Bruker AXS GmbH
Bruker AXS Inc.
Berlin · Germany
Phone +49 (30) 670990-0
Fax +49 (30) 670990-30
[email protected]
Karlsruhe · Germany
Phone +49 (7 21) 50997-0
Fax +49 (7 21) 50997-5654
[email protected]
Madison, WI · USA
Phone +1 (608) 276-3000
Fax +1 (608) 276-3006
[email protected]
www.bruker.com
© 2013 Bruker Nano GmbH. Printed in Germany.
Description
All configurations and specifications are subject to change without notice. Order No. DOC-S81-EXS003.
Technical Specifications