Applies to: Chemical and Gas IlluminatIR (FTIR) Tickets Solved: 0 Rank: 7
Sample Thickness - Too thin of a sample will look very “grassy” or noisy. A different particle needs to be analyzed or more scans should be performed. A thick sample will have an absorbance greater than 0.8 and top out the peaks. The sample should be flattened or the operator should move to a different part of the slide.
The sample must be flat on the slide. If the sample is not flat the baseline will not be flat. If the sample is not pressed flat on the slide, a baseline correct can be used in post processing, or another particle should be analyzed.
Sample not centered in aperture - If the sample is not centered the result will again be “grassy” or noisy. The sample should be centered and re-analyzed.
Aperture size incorrect:
The aperture selected should not be greater than 20% of the particle being analyzed. A baseline that tilts upward from right to left is considered to be a result of scatter. A smaller aperture should be selected and a new background and sample analyzed.
Upward- or downward -pointing peaks near 3800, 2300 and 1600 cm-1 in sample absorbance spectrum indicates high abundance of H2O and CO2. A new background should be conducted and the sample should be re-analyzed.
Granular - Move to a different part of the slide and re-analyze the sample.
Reflective - When a sample is reflective negative peaks are observed in the results. Prepare a thinner sample or move to a different particle and re-analyze.
Too Small - Too small of a sample will look very “grassy” or noisy. Find a larger particle with same spectral features.
For detailed instructions please see attached document.
For further questions or troubleshooting please contact technical support.
Our SMEs are standing by to assist with issues and repairs.
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Keywords: size, focus, preparation, thickness, flat, centered, aperature, baseline, uneven, tilt, background, CO2, bad results