Analytical techniques

You will be able to

• Use the characteristic infrared absorption ranges in the Data section to identify bonds and functional groups from a spectrum.
• Distinguish an alcohol, a carboxylic acid, a ketone and an ester using the O–H and C=O absorptions.
• Deduce the compound from an infrared spectrum of a simple molecule by combining the functional groups present and absent.

You will be able to

• Deduce the molecular mass of a compound from the molecular ion peak, and suggest the ions formed by simple fragmentation.
• Deduce the number of carbon atoms n from the [M+1]⁺ peak using n = 100 × abundance of [M+1]⁺ ÷ (1.1 × abundance of M⁺).
• Deduce the presence of chlorine or bromine from the [M+2]⁺ peak and use it to find the molecular formula.