Raman spectroscopy is a non-destructive analytical technique based on the inelastic scattering of monochromatic light, usually from a laser source. When the light interacts with the molecules in a sample, it causes a shift in the energy of the scattered photons, which is known as the Raman shift. This shift is unique to the vibrational modes of the molecules and provides a molecular fingerprint that can be used to identify specific compounds in a mixture.To identify the presence of a specific compound in a mixture using Raman spectroscopy, one needs to follow these steps:1. Obtain a pure reference spectrum of the compound of interest. This can be done by measuring the Raman spectrum of a pure sample of the compound or by referring to a database of Raman spectra.2. Measure the Raman spectrum of the mixture. This involves illuminating the sample with a monochromatic light source usually a laser and collecting the scattered light using a spectrometer.3. Compare the Raman spectrum of the mixture to the reference spectrum of the compound of interest. If the characteristic Raman bands peaks of the compound are present in the mixture's spectrum, it indicates the presence of the compound in the mixture.However, there are several limitations and challenges associated with using Raman spectroscopy to identify specific compounds in mixtures:1. Overlapping bands: If the mixture contains multiple compounds with similar or overlapping Raman bands, it can be challenging to distinguish the compound of interest from other components in the mixture.2. Fluorescence interference: Some compounds exhibit strong fluorescence when excited by the laser, which can overwhelm the weaker Raman signal and make it difficult to detect the compound of interest.3. Low sensitivity: Raman scattering is inherently a weak phenomenon, and detecting trace amounts of a compound in a mixture can be challenging, especially if the compound has a weak Raman scattering cross-section.4. Sample preparation: The quality of the Raman spectrum depends on the sample's physical state, homogeneity, and particle size. In some cases, sample preparation may be required to obtain a reliable spectrum.5. Matrix effects: The presence of other compounds in the mixture can sometimes affect the Raman spectrum of the compound of interest, either by enhancing or suppressing its Raman bands.Despite these limitations, Raman spectroscopy remains a valuable tool for identifying specific compounds in mixtures due to its non-destructive nature, minimal sample preparation requirements, and the ability to analyze samples in various physical states solid, liquid, or gas . Advances in instrumentation, such as the development of portable Raman spectrometers and the use of surface-enhanced Raman scattering SERS , continue to improve the sensitivity and applicability of this technique.