Infrared data analysis can involve peak identification, where each peak is assigned to a specific functional group or bond type. Specific analysis projects include: peak identification, peak comparison, semi-quantitative peak analysis, peak deconvolution, protein secondary structure analysis,two-dimensional infrared analysis, and other types of analyses.

Infrared testing generally involves methods such as potassium bromide (KBr) pellet method, ATR (Attenuated Total Reflection), and liquid sample cell method.

• The KBr pellet method is suitable for powder samples, but it may introduce background peaks from KBr. To mitigate this, we typically subtract both KBr and air background (specific methods can be requested by clients). This subtraction helps reduce the interference caused by KBr, especially due to its tendency to absorb moisture and the resulting hydroxyl peaks.
• ATR is suitable for various solids, bulk films, and liquids that cannot be ground into powder. The advantage of ATR is that there is no interference from other impurity peaks, but some peaks may be weaker for certain samples.
• The liquid sample cell method is generally used for liquid samples, but if KBr windows are used, the sample should not contain water or react with KBr.

Transmittance spectra tend to highlight smaller peaks, which may sometimes make it easier to visually assess a sample. Absorption spectra have a linear relationship with concentration (while transmittance spectra do not). This makes absorbance suitable for quantitative analysis, spectral subtraction, and other operations. In peak refinement analysis, absorbance is often used due to the linearity of the spectral feature.

In infrared testing, absorbance and transmittance data can be converted using .