How do you interpret FTIR ATR?

When interpreting ATR-FTIR spectra where quantitative results are important, note that non-corrected ATR spectra have much stronger absorbance bands at longer wavelengths (smaller wave numbers) than at shorter wavelengths (larger wave numbers) compared to normal FTIR transmittance spectra.

What is difference between ATR and FTIR?

All Answers (15) FTIR is any Fourier Transform Infrared spectroscopy method in any measuring geometry, may it be transmission, reflection or whatever. ATR stands for attenuated total reflection and is developed in order to enhance the surface sensitivity since IR spectroscopy is a bulk method.

What do FTIR peaks mean?

In FTIR, an increase in the peak intensity usually means an increase in the amount (per unit volume) of the functional group associated with the molecular bond, whereas a shift in peak position usually means the hybridization state or electron distribution in the molecular bond has changed.

Why ATR is used in FTIR?

ATR works well for these samples because the intensity of the evanescent waves decays exponentially with distance from the surface of the ATR crystal, making the technique generally insensitive to sample thickness.

What is the main advantage of the ATR method?

One of the key advantages of ATR-FTIR imaging is that it requires minimal or no sample preparation prior to spectral measurements. This is due to the fact that the penetration depth of IR light in the sample for ATR measurements is independent of sample thickness.

What is ATR analysis?

Attenuated total reflection infrared (ATR-IR) spectroscopy is used for analysis of the surface of materials. It is also suitable for characterization of materials which are either too thick or too strong absorbing to be analyzed by transmission spectroscopy.

What does a decrease in FTIR peaks intensity show?

In spectroscopy, absorbance vs energy has been plotted in FTIR diagrams. The bond energy was represented by kayser (cm^-1). Therefore, more decline in the energy peak indicates a more micro-structure chemical bond.

What determines peak intensity in IR?

The most important factor that influences the intensity of an IR absorption band is the change in dipole moment that occurs during a vibration. For example, an aldehyde C=O. stretch usually occurs near 1730 cm⁻¹. An alkene C=C stretch usually occurs near 1650 cm⁻¹.

Is ATR a type of FTIR?

Spectroscopy Simplified: ATR Sampling in FTIR Attenuated Total Reflection (ATR) sampling revolutionized FTIR spectroscopy, with its simplicity of sample handling and near-universal applicability.

What are the advantages of ATR-FTIR as compared to other sample introduction methods?

What makes a good ATR crystal?

Refractive Index – the crystal should have a higher index of refraction than the sample. The majority of organic samples have refractive indices in the area of 1.5. Refractive indices of standard ATR crystals span from 2.4 to 4.0 – which in most cases provides sufficient sample to crystal differentiation.