Thermo Fisher Scientific 269-354500 Smart Diffuse Reflectance User Guide
- August 17, 2024
- Thermo Fisher SCIENTIFIC
Table of Contents
- 269-354500 Smart Diffuse Reflectance
- Smart Diffuse Reflectance Specifications
- Product Components
- Sample Holder
- Storage Compartment
- Optical Unit
- Si-Carb Sampling Tool
- Starting the Software
- Installing the Smart Diffuse Reflectance Accessory
- Installing a Sample Holder
- Q: Can I use other sample holders with the Smart Diffuse
269-354500 Smart Diffuse Reflectance
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Smart Diffuse Reflectance Specifications
- Maximizes diffusely scattered radiation
- Minimizes spectral interference
- Includes two sample holders
- Comes with Si-Carb sampling kit and premeasured packets of
KBr
Product Components
Sample Holder
The sample holder slides into the sample port in the Smart
Diffuse Reflectance accessory and presents the sample surface at
the focal point of the infrared beam. Two types of sample holders
are provided:
-
Double-cup holder: Includes cups for sample
material and background material. -
Single-cup holder: Features a trough for the
platen from the Si-Garb sampling tool and a gold disk for
performance tests.
Storage Compartment
The accessory provides a compartment for storing tools and
accessories, capable of holding two sample holders, the Si-Garb
sampling kit, and packets of KBr.
Optical Unit
The optical components are mounted in a sealed tube that
automatically connects to the purge system in your IR
spectrometer.
Si-Carb Sampling Tool
Included in the accessory for specific sampling needs.
Product Usage Instructions
Starting the Software
To begin measuring and analyzing samples, start the OMNIC
Paradigm software. For detailed instructions, refer to the guides
and tutorials available at www.knowledge1.thermofisher.com.
Installing the Smart Diffuse Reflectance Accessory
-
Ensure the spectrometer is turned on.
-
If present, remove the sample compartment cover.
-
Remove any side wall adapters inside the sample
compartment. -
Disconnect any cables from the back of the sample
compartment. -
Remove any existing accessories from the sample
compartment. -
Insert the accessory by gently lowering it into the sample
compartment until it locks in place.
Installing a Sample Holder
Both sample holders fit in the Smart Diffuse Reflectance
accessory similarly. To install a sample holder, slide it into the
sample port at the front of the accessory. The reflective disk
should be used for performance tests.
Frequently Asked Questions (FAQ)
Q: Can I use other sample holders with the Smart Diffuse
Reflectance accessory?
A: The accessory is designed to work with the provided sample
holders to ensure optimal performance and compatibility. The use of
other holders may affect results.
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Smart Diffuse Reflectance
This tutorial introduces the Smart Diffuse Reflectance accessory from Thermo
Fisher Scientific. This accessory is designed for fast analysis of powder
samples using the standard diffusereflectance technique and is compatible with
Thermo Scientific Nicolet Series Fourier Transform Infrared (FTIR)
spectrometers. In this tutorial, you will learn the basics of diffuse-
reflectance sampling with your spectrometer. It explains how to install the
accessory in the spectrometer sample compartment and use the accessory to
analyze powders. You will also learn how to maintain and store the accessory
when it is not in use.
Product features
The Smart Diffuse Reflectance accessory is a general-purpose sampling
accessory for basic diffuse-reflectance analyses. This accessory offers the
throughput, ruggedness, and stability needed for most quality control and
research applications using standard diffuse-reflectance optics and ambient
conditions. The Smart Diffuse Reflectance accessory is designed for fast
analysis of organic and inorganic solids and powders using the standard
diffuse-reflectance technique. A special tool for collecting and analyzing
surface samples is also included.
Smart accessory features
The Smart Diffuse Reflectance accessory is part of our extensive family of
Smart Accessories for Nicolet Series spectrometers. All Smart accessories
offer the following features:
· Pinned-in-place, permanently aligned optics. · Fully integrated design.
269-354500 Revision B January 2024 Thermo Fisher Scientific All rights
reserved.
Smart Diffuse Reflectance Product features
· Snap-in installation. · Automatic purging. · Automatic recognition. ·
Automatic measurement settings.
Smart Diffuse Reflectance specifications
The Smart Diffuse Reflectance accessory features: · Sample holders: Si-Carb
and powder · Sample cup capacity: -0.25 gram · KBr packets: 25 premeasured 0.5
gram packets of high quality KBr powder, ground to the correct particle size
for diffuse-reflectance measurements · Silicon-carbide disks: adhesive-backed,
silicon-carbide disks; 100 each 320-grit and 400-grit disks
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Smart Diffuse Reflectance Product features
Product components
The Smart Diffuse Reflectance accessory effectively maximizes diffusely
scattered radiation while minimizing specular reflection, which is a source of
spectral interference. The accessory comes with two sample holders, a Si-Carb
sampling kit, and premeasured packets of KBr.
Component Sample holder
Description
The sample holder slides into the sample port in the Smart Diffuse Reflectance
accessory and presents the sample surface at the focal point of the infrared
beam. Two types of sample holders are provided with the accessory.
Double-cup holder: The standard sample holder has two cups, one for the sample
material and one for the material used to measure the background. Each cup
holds approximately 0.25 gram.
Single-cup holder: The other sample holder has a trough in the front position
to hold the platen from the Si-Garb sampling tool. A gold disk mounted in the
back position is used for the performance test and some background
measurements.
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Smart Diffuse Reflectance Starting the software
Component Storage compartment
Optical unit
Si-Carb sampling tool
Description
The Smart Diffuse Reflectance accessory provides a handy compartment for
storing tools and accessories when they are not being used. The compartment is
large enough to hold two sample holders. the Si-Garb sampling kit and several
premeasured packets of KBr.
The optical unit is a sealed tube that contains an aluminum base supporting a
parabolic mirror. The input mirror focuses the beam from the IR spectrometer
on the surface of the sample. The output mirror collects the scattered IR
energy emitted from the sample and directs the energy to the detector in the
IR spectrometer. The optics tube is connected to the purge system in the IR
spectrometer. This design maintains a controlled environment around the IR
beam as it travels through the accessory and eliminates water and carbon
dioxide peaks in the infrared spectra.
The Smart Diffuse Reflectance accessory comes with a Si-Carb sampling kit. The
kit includes a probe, two platens, and two packets of silicon-carbide papers
in 320- and 400-grit particle sizes. The tool is used to sample large
intractable solids such as the painted surface of a piece of equipment or an
automobile. To collect a surface sample, you simply rub the sample surface
with siliconcarbide paper and then measure the particles adhering to the
paper. A reflective disk is used for the performance test and some background
measurements.
Starting the software
To measure and analyze samples, start OMNIC Paradigm software. For
instructions on using OMNIC Paradigm software, see the guides and tutorials at
www.knowledge1.thermofisher.com
4
Smart Diffuse Reflectance Installing the Smart Diffuse Reflectance accessory
Installing the Smart Diffuse Reflectance accessory
The accessory fits into guides on the side walls of the sample compartment.
These accessories are aligned at the factory and they require no further
adjustment. The optical components are mounted in a sealed tube, which
automatically connects to the purge system in your IR spectrometer.
To install the Smart Diffuse Reflectance accessory 1. Make sure the
spectrometer is turned on. 2. If the sample compartment cover is attached,
remove it. 3. If the side wall adapters are in place inside the sample
compartment, remove them. 4. If you were using any of the connectors at the
back of the sample compartment, remove the
cables. 5. Remove the Snap-in baseplate or any other accessories installed
inside the sample com-
partment. 6. Insert the accessory. Lower the accessory into the spectrometer
sample compartment and
press gently downward until the accessory locks in place.
Installing a sample holder
Two types of sample holders are provided with the Smart Diffuse Reflectance
accessory: · a double-cup sample holder for measuring a powder sample and
background and · a single-cup sample holder with a reflective (gold) disk for
use with the Si-Carb sampling tool.
Both sample holders fit in the Smart Diffuse Reflectance accessory in the same
way.
To install a sample holder Slide the single-cup sample holder (the one with
the reflective disk) into the sample port at the front of your Smart Diffuse
Reflectance accessory. The reflective disk will be used to run the performance
test.
5
Smart Diffuse Reflectance Installing the Smart Diffuse Reflectance accessory
Note To position the reflective disk in the infrared beam, push the sample
holder all the way in and then pull it out slightly until you feel the holder
click into position.
Changing your measurement settings
When you install a Smart Accessory, the system automatically updates the
measurement settings to those associated with the accessory. The default
settings for the accessory have already been optimized for collecting data
with the accessory. After you install the accessory, the accessory name is
shown in the Settings list on the dashboard of OMNIC Paradigm software.
Running the performance test
Run the Accessory Performance Test workflow to verify the performance of your
accessory. 1. From the dashbaord of OMNIC Paradigm software, right-click the
Accessory Performance
Test workflow and select Run. 2. Follow the prompts to complete the workflow.
When the workflow is complete, you can find the test report in the Reports
section of the dashboard.
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Preparing a sample for analysis
Smart Diffuse Reflectance Preparing a sample for analysis
Preparing a powder sample
Powders are easier to run by diffuse-reflectance than by IR transmission
because little or no preparation is required. When analyzed by IR
transmission, powders must be mixed with the proper amount of KBr and pressed
into a pellet. The pellet is then placed in the IR beam. When a diffuse-
reflectance accessory is used, powders are placed directly in the sample
holder or mixed with a premeasured packet of KBr and then poured into the
sample holder. The sample holder is then inserted into the sample port of the
diffuse-reflectance accessory and data collection can begin.
To prepare a powder sample
1. Grind the sample as finely as you can. A particle size of 2 to 5
micrometers is recommended. You can use a mortar and pestle or an electric
grinder to grind the sample. One to two minutes of grinding is usually
sufficient. Grind the sample slowly to avoid creating heat due to friction;
vigorous grinding may change the chemical structure of some samples.
The WIG-L-BUG electric grinder, available from Thermo Fisher Scientific, is
designed to grind samples to the correct particle size for diffuse-reflectance
measurements.
2. Dilute the sample with a diffusely scattering matrix material (optional).
Some powders can be analyzed neat (without dilution). If the sample is highly
absorbing or has a high refractive index (it’s difficult to tell just by
looking at it), it should be mixed with a diffusely scattering matrix material
such as KBr, KCI, or diamond powder. Make sure you use a high quality (ground
and dried) matrix. If the particles are bigger than 5 micrometers, use a clean
mortar and pestle or an electric grinder to grind the matrix material. Don’t
grind the sample and matrix together.
Note The premeasured packets that come with your Smart Diffuse Reflectance
accessory contain high quality KBr that has been thoroughly dried and ground
to the correct particle size. As a general rule, mix the sample with the
matrix material in the following ratio (by weight):
7
Smart Diffuse Reflectance Preparing a sample for analysis
· For organic samples: 10% sample to 90% matrix · For inorganic samples: 2 to
5% sample to 95 to 98% matrix The sample cup can hold about 0.25 gram of
powder. However, you should make enough to fill the cup to overflowing. For
example, to prepare 0.5 g of organic sample, mix 0.05 g of sample material to
0.45 g of matrix. 3. Open the storage compartment on top of the Smart Diffuse
Reflectance accessory and remove the sample holder that has two sample cups.
4. Fill the front cup with your sample. Fill the cup to overflowing. Be
careful not to tap the sample holder when pouring in the powder. Tamping packs
the particles too closely and may reduce the sensitivity of the analysis. When
the cup is filled, place the sample holder on a flat surface and level the
sample surface with a spatula. This reduces reflections off the sample surface
and helps ensure reproducible results. 5. Fill the back cup with the reference
material. If the sample is undiluted, fill the back cup with a non-infrared
absorbing matrix such as potassium bromide (KBr). If you diluted your sample
in a matrix material, such as KBr, KCI or diamond powder, fill the back cup
with the pure matrix. Be sure to follow the same procedure when placing the
background material in the sample cup as you used for the sample.
Grinding a solid sample
The diffuse-reflectance technique can be used to measure homogeneous solids by
grinding a representative sample and analyzing the powdered material. This
works for any organic or inorganic solid that can be ground into a fine powder
(particle size of2 to 5 micrometers).
To grind a solid sample 1. Prepare the sample by grinding it to a fine powder.
You can use a mortar and pestle or an elec-
tric grinder to grind the sample (2 to 5 micrometer particle size is
recommended). Grinding for 1 to 2 minutes is usually sufficient. 2. Follow the
instructions for preparing a powder sample.
8
Smart Diffuse Reflectance Preparing a sample for analysis
Dissolving a solid sample
The diffuse-reflectance technique can also be used to analyze solids that are
dissolved in a solvent by mixing with a powdered supporting matrix such as
potassium bromide and then evaporating the solvent and analyzing the residue.
- Prepare a 10 to 25% solution of sample to solvent and mix the solution
well. 2. Fill the front sample cup with a powdered supporting matrix such as
KBr. Fill the cup to over-
flowing and then level the surface with a spatula. 3. Use a syringe to drop 100 micrometers or so of the sample mixture onto the powdered matrix. 4. Wait for the solvent to evaporate completely and then follow the instructions for preparing a
powder sample.
Collecting a surface sample
The Si-Carb (silicon carbide) sampling tool can be used to sample the surface layer of any solid. This works well for sampling large, intractable solids, such as the painted surface of a piece of equipment or an automobile To collect a surface sample 1. Open the storage compartment on top of the Smart Diffuse Reflectance accessory and
remove the sample holder that has one sample cup and a gold disk. 2. Remove the probe and platen from the storage compartment and screw the platen onto the
probe.
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Smart Diffuse Reflectance Preparing a sample for analysis
3. Select a silicon carbide paper with the appropriate grit size. Use the
320-grit paper for soft coatings such as paint. Harder materials may require a
more abrasive paper such as diamond paper. The higher the grit size the
smaller are the particles adhering to the paper. Handle the paper gently to
avoid contaminating the surface.
4. Remove the protective cover from the back of the paper and lightly touch
the platen with the adhesive.
5. Use the protective cover to press the paper firmly onto the platen. 6. Use
the tool to abrade the sample surface. Gently rub the paper against the sample
surface
for 1 to 2 seconds. 7. Unscrew the platen from the probe. Be careful not to
touch the paper with your fingertips. 8. Place the platen, with the paper side
up, into the sample cup. When the platen is seated prop-
erly, the surface of the platen will be flush with the edges of the sample
holder.
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Measuring the background
Smart Diffuse Reflectance Measuring the background
A background spectrum is needed to process the sample data to an infrared spectrum. The background is a reference spectrum which accounts for the unique optics of the diffusereflectance accessory and spectrometer. Each sample spectrum is ratioed against a background so that the final spectrum is free of these features.
Choosing the background material
When measuring powders that are mixed with a diffusely-scattering matrix such
as KBr, the pure matrix is used for the background measurement. Use KBr for
the background measurement if the sample is undiluted. When the silicon-
carbide sampler is used, the gold disk or a clean Si-Carb paper is used for
the background. If you use the gold disk to measure the background, your
spectra will have a large silicon-carbide band around 850 cm-1.
Eliminating the silicon-carbide band
If your sample absorbs near 850 cm-1, you may be able to eliminate the
silicon-carbide band in your sample spectrum by using a blank silicon-carbide
paper for the background. Be sure to use the same grit size as you used for
the sample and collect a thin layer of sample.
Measuring the background
The background data used to process each sample measurement to an IR spectrum
must be measured under exactly the same conditions as the sample.
To measure the background 1. Insert the sample holder into the Smart Diffuse
Reflectance accessory. To position the back-
ground material under the IR beam, push the sample holder all the way in and
then pull it out slightly until you feel the holder click into position. 2.
Collect a background spectrum. Click Preview and Measure Background on the
dashboard.
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Smart Diffuse Reflectance Measuring the background
Background spectrum
After you collect a new background, the background spectrum will be used to
process all of your sample measurements until you replace it by collecting
another background spectrum. Figure 1-1: Figure: Background of potassium
bromide
Figure 1-2: A background spectrum collected using the gold disk.
Figure 1-3: A background spectrum collected using a blank 320-grit silicon-
carbide paper
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Smart Diffuse Reflectance Measuring the sample
When to collect a new background
The background data used to process each sample measurement to an IR spectrum
must be measured under exactly the same conditions as the sample. For best
results, we recommend collecting a background spectrum before each sample. If
you use the same sampling technique and instrument settings to analyze all of
your samples, you can use the same background to process multiple samples.
However, we recommend collecting a new background at least once every two
hours. If any of the following is true, you should immediately remeasure the
background and use the new background to process your sample data.
· You changed a component in your spectrometer or sampling accessory · You
changed one of the measurement settings other than Gain, Final Format, or
Sample
Scans. · You see a change in the amount of water or carbon dioxide bands in
the IR spectra of your
samples. · You see an unexpected change in the spectral baseline. · The
quality of your spectral data is reduced (more noise or spurious peaks in the
spectrum).
Measuring the sample
Once the background data are collected, move the sample into the infrared beam
and measure the sample. The sample measurement will show how the energy you
started with was reduced by the sample.
To measure the sample 1. Move the sample into the infrared beam. Slide the
sample holder out about 3 cm (1 inch). You
should feel it click into position.
13
Smart Diffuse Reflectance Measuring the sample
2. Measure the sample.
Sample spectrum
When % Reflectance is selected as the final format of your sample spectra, the
software displays a reflection spectrum. A reflection spectrum looks similar
to a transmission spectrum. The spectrum is updated as new data are collected.
When the system has collected the number of scans specified, the final
spectrum is displayed in a window. The final spectrum shows only the change in
IR energy (the background energy has been removed). Figure 1-1: A spectrum of
sodium benzoate diluted with potassium bromide
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Cleaning between samples
Smart Diffuse Reflectance Cleaning between samples
Clean the sample holder after you finish measuring each sample.
You can clean the holder with soap and water or with a solvent such as
acetone. If you clean the holder with a solvent, allow enough time for the
solvent to evaporate completely. To ensure complete evaporation, dry the
sample cups with clean, dry air or nitrogen.
When the cups are clean and dry, you are ready to pour in the next sample.
Removing the accessory
You can remove the Smart Diffuse Reflectance accessory as easily as you
installed it. When not in use, your accessory should be stored in a dust-free
environment, such as a cabinet or box. To remove the accessory: 1. If a sample
holder was left in the accessory, remove and clean the sample holder and then
place it in the storage compartment on top of the Smart Diffuse Reflectance
accessory. 2. Gently pull up on the accessory to release it. Continue lifting
the accessory straight up until it
is completely free of the sample compartment.
15
Smart Diffuse Reflectance Next Steps
Next Steps
For more information on using OMNIC Paradigm software to measure and analyze
samples, see the guides and tutorials at www.knowledge1.thermofisher.com
16
References
Read User Manual Online (PDF format)
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