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Breakerspace FTIR Tutorial

Overview:

FTIR spectrometer The Nicolet iS5 Fourier-transform infrared (FTIR) spectrometer provides an infrared spectrum of absorption or transmission of a solid, liquid, or gas, for identification, primarily, of organic or polymeric materials. This tutorial focuses primarily on use of the instrument with an attenuated total reflectance (ATR) accessory, which allows for easy sampling of materials in solid, semi-solid, powder, paste, and liquid forms. The Breakerspace has an iD7 attenuated total reflectance (ATR) accessory that is left on the instrument by default, and also an iD1 transmission accessory and a Pike Technologies EasiDiff diffuse reflection accessory.

Index:

Standard operating protocol:

Instrument startup:

Operation:

Repeat steps as needed

Instrument shut down:

Compatible materials and sample prep:

If you have any questions about whether a material is appropriate to characterize in the Breakerspace, please ask before bringing it to the lab.

Detailed operating instructions:

ATR Sample preparation and loading:

To maximize signal strength, it is important that the sample is in good contact with the entire ATR window.

Be sure to collect a background before loading samples

Solid samples:

Although many solid samples will not contaminate the window, it is still a good idea to wipe the window with isopropyl alcohol and a Kimwipe between samples.

Solid sample loading.
Loading a solid sample

Powder samples:

It is especially important that powders contact the surface of the diamond window as completely as possible, so it is helpful that they are ground as finely as possible. It is helpful to load powders in preview mode and verify the pressure tip is pushing the powder into intimate contact with the ATR crystal before collecting a spectrum.

Powder sample loading.
Loading a powder sample

Liquid samples:

Liquid sample loading.
Loading a non-volatile liquid sample

Cleaning the ATR crystal:

Cleaning the ATR crystal.
Cleaning the ATR crystal

Experiment setup:

Experiment setup allows you to change the parameters to fit your requirements. For faster collections, reduce the number of scans and/or scan resolution, and note how the estimated time changes. To improve the signal to noise ratio, increase the number of scans.

There are two ways to collect a spectrum (either background or sample): with preview on or off. If the Preview data collection parameter is selected, the instrument will show a live spectrum that refreshes approximately every second during preview mode. Once you are satisfied with your sample setup, run the full scan by by clicking start collection in the upper right. Deselect Preview data collection if you wish to bypass the preview stage and run your full scan immediately. This setting will apply to both background and sample collection.

For a comprehensive explanation of the parameters in experiment setup, select help in the lower left.

experiment setup

Preview data collection enabled:
Background and sample collection with Preview data collection on.
Background and sample collection with Preview data collection on
Background and sample collection with Preview data collection on in the OMNIC software.
Background and sample collection with Preview data collection on in the OMNIC software
Preview data collection not enabled:
Basic sample collection without Preview data enabled.
Basic sample collection without preview data enabled

Background collection:

Before collecting spectra, it is necessary to collect a background spectrum.

A background spectrum is a single-beam spectrum obtained without a sample in place. The background spectrum is the result of the output of the source; the response of the beamsplitter, optics, sampling accessory or holder, and detector; and any atmospheric absorptions inside the spectrometer. A single-beam sample spectrum can be ratioed against the background spectrum to remove the effects of the background and produce a transmission spectrum. (Definition from the Thermo Scientific OMNIC Help Topics)

Negative absorbance in an ATR spectrum indicate the crystal was not clean during background collection.

Sample collection:

Once your background is collected you are ready to collect a spectrum for your sample. Load it according to the above instructions, and click collect sample, following the process based on your experiment setup.

Volatiles cover:

Volatile cover use.
Use of the volatile cover

Pressure tips:

concave and self-leveling pressure tips.
Concave (left) and self-leveling (right) pressure tips
Swapping pressure tips.
Swapping pressure tips

Data processing and analysis:

Data processing is beyond the scope of this tutorial, but we recommend the use of the Wiley KnowItAll Spectroscopy Software & Libraries available through the MIT Libraries.

Common failure modes:

Manufacturer’s manuals:

Exercises: