Q: I can see noise near 4000 to 3400 cm^-1 and 2000 to 1300 cm^-1 in the spectrum. How can I get rid of it?

A : The noise near 4000 to 3400 cm^-1 and 2000 to 1300 cm^-1 results from the absorption of water vapor (H2O). As the quantity of water vapor fluctuates due to environmental changes, the absorption appears as noise. In addition to water vapor, the absorption by carbon dioxide (CO2) may be observed near 2350 cm^-1 and 670 cm^-1.
By performing the sample measurement as soon as possible after the background measurement, the effects of water vapor and carbon dioxide can be minimized. Alternatively, purging with dry air or nitrogen can be used to minimize the effects. However, purging requires a nitrogen cylinder or equipment to supply dry air.
The LabSolutions IR software offers an atmosphere correction function to eliminate this effect. The atmosphere correction function makes it simple to reduce the effects of water vapor and carbon dioxide.