![]() Overall, it’s important to address interferences before you attempt to assign other peaks, and learning to recognize where the noise is coming from will make you more efficient in reducing it. Some IR software also include atmospheric correction functions that can clean up artifacts after the fact. 2 When you notice these artifacts appearing in the spectrogram, some options include trying again with a fresh background, purging the instrument with dry nitrogen or changing your desiccant to better reign in water activity. First, it’s important to perform the measurement run as soon as you can after running the background, as water and CO 2 levels in the instrument can tend to fluctuate. Noise and atmospheric peaks can be eliminated either by taking steps to prevent them during the run or by using digital methods to correct them. Depending on the severity of the interference, ambient water and CO 2 can leave quite large artifact peaks in the spectrogram – locating and identifying these interferences should be among the first steps you take when examining the spectral output. Noise around 4000 to 3400 cm - to 1300 cm -1 typically comes from water vapor, while noise near 2350 cm -1 and 670 cm -1 comes from CO 2, which is easy to see in a background run. Noise in the spectrogram is easy to spot from the “fuzzy” appearance of the baseline. 1 Obtaining a flawless spectrogram for every run would be a miracle, but knowing how to identify interferences in the spectra and how to mitigate them are important precursors for successful qualitative analyses. Identify and avoid common spectral interferencesĪn ideal, easy-to-read IR spectrogram would have low noise, a flat baseline and no artifacts from atmospheric interferences like water and carbon dioxide. ![]() ![]() Here are a few tips to speed and simplify your analysis when investigating IR spectra:ġ. The transmittance or absorbance spectra of a sample can reveal which functional groups are present, as well as a unique “fingerprint” for each substance, but accurate and efficient identifications rely on both a high quality spectrogram and the skills and resources to interpret it. Used in numerous applications ranging from environmental to pharmaceutical to forensic, IR spectroscopy can provide both qualitative and quantitative information about the compounds present in a liquid, solid or gaseous sample. Infrared (IR) spectroscopy, a form of vibrational spectroscopy, offers useful information for a wide range of both organic and inorganic samples. ![]()
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