A concise summary of common UV-Vis and IR instruments, their purposes, and typical peaks
This information on the page is very important for any exam, viva or interview. Here is the purposes and common peaks that you should know while attending in an interview as a chemistry student.
UV-Vis Spectrophotometer
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Purpose: Measures absorption of UV (200–400 nm) and visible (400–800 nm) light by molecules, mainly to study electronic transitions (π→π*, n→π*).
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Common Peaks:
Type of Transition Wavelength Range (nm) Typical Compounds π → π* 180–250 Alkenes, Aromatics n → π* 250–350 Carbonyls, Nitrogen compounds Charge Transfer 300–500 Complexes, Donor–Acceptor molecules
Also read:
IR Spectrometer (FTIR)
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Purpose: Measures absorption of infrared radiation by molecules, giving information about functional groups and bond vibrations.
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Common Peaks:
Functional Group Wavenumber (cm⁻¹) O–H (alcohol/acid) 3200–3600 N–H (amine/amides) 3300–3500 C=O (carbonyl) 1650–1750 C=C (alkenes/aromatics) 1600–1680 C–H (alkane) 2850–2960 C–O (ethers, alcohols) 1050–1150