Infrared spectrometry and mass spectrometry are two of the most powerful analytical techniques used in environmental chemistry for the detection, identification and quantification of pollutants and trace components present in air, water, soil and biological samples. Both methods operate on distinct principles, utilize specialized instrumentation, and have wide-ranging applications that help in monitoring pollution, assessing environmental quality, and understanding the fate of contaminants in the ecosystem. Their relevance has increased as environmental challenges have become more complex, requiring sensitive and reliable analytical tools for comprehensive chemical analysis. The principle of infrared (IR) spectrometry is based on the absorption of infrared radiation by molecules, which causes vibrations in the chemical bonds. Each type of bond, depending on its atomic masses and bond strength, absorbs energy at characteristic wavelengths, leading to a unique spectrum known as a molecular fingerprint. This spectrum enables the identification of functional groups and structural characteristics of a compound. Infrared radiation lies in the wavelength range of 2.5 to 25 micrometers, corresponding to frequencies between 4000 and 400 cm⁻¹. When IR radiation passes through a sample, certain frequencies are absorbed and recorded as peaks in the spectrum. The position and intensity of these peaks provide qualitative and quantitative information about the sample composition. The instrumentation of IR spectrometry generally consists of a radiation source, monochromator, sample holder, detector and recorder. The IR source is usually a Nernst glower or a Globar that emits radiation across the infrared region. The monochromator, such as a prism or grating, is used to isolate specific wavelengths of radiation. The sample may be analyzed in solid, liquid, or gaseous form using specialized sample holders or cells. Detectors such as thermocouples, bolometers, or pyroelectric devices measure the intensity of transmitted or absorbed radiation. Modern instruments often employ Fourier Transform Infrared (FTIR) technology, which uses an interferometer instead of a monochromator, enabling rapid scanning, higher resolution, and improved signal-to-noise ratio. The resulting interferogram is mathematically transformed into a spectrum using Fourier transformation. In environmental applications, IR spectrometry has a significant role in analyzing pollutants and monitoring chemical changes. It is particularly effective for identifying organic compounds such as hydrocarbons, pesticides, solvents, and industrial by-products. Air pollutants like carbon monoxide, sulfur dioxide, nitrogen oxides, and volatile organic compounds can be detected by their characteristic absorption bands in