FT-IR Troubleshooting Guide: How to Solve Common Problems in Infrared Spectroscopy

If you’ve ever run an Fourier transform infrared (FT-IR) sample only to have the spectrum look “off,” you’re not alone. Noisy data, strange negative peaks, or distorted baselines are some of the most common frustrations FT-IR users face. The good news is that most of these issues have straightforward explanations—and simple solutions.

This explainer video walks through four of the most common FT-IR problems and how to solve them, drawing from insights first published in Spectroscopy's article, "Common Problems with FT-IR Instruments and How to Avoid Them".

Here’s a quick look at the “case files” covered in the video:

1. Instrument Vibrations – FTIR spectrometers are highly sensitive. Even small physical disturbances from nearby pumps or lab activity can introduce false spectral features. Keeping your setup vibration-free is key to getting clean data.
2. Dirty ATR Crystals – Attenuated Total Reflection (ATR) accessories are popular for their ease of use, but a contaminated crystal can cause negative absorbance peaks. A quick clean and fresh background scan usually resolves the issue.
3. Surface vs. Bulk Effects – With materials like plastics, the surface chemistry may not match the bulk. Collecting spectra from both the surface and a freshly cut interior can reveal if you’re dealing with surface oxidation or additives.
4. Incorrect Data Processing – In diffuse reflection, processing data in absorbance units can distort spectra. Converting to Kubelka-Munk units provides a more accurate representation for analysis.

By keeping these four checkpoints in mind—instrument stability, accessory cleanliness, sample integrity, and proper data processing—you can troubleshoot most FTIR problems quickly and confidently.

Whether you’re new to spectroscopy or an experienced analyst, building this troubleshooting mindset helps ensure your data is reliable and reproducible.

This video was created using Gamma and NotebookLM.