Table 1.

Fatty acid spectral assignments. Key assignments from Raman spectra of alkyne tagged and untagged C14, C16 and C18 fatty acids and their peak position for each species. Spectra were acquired using 532 nm laser excitation, 50%/ca. 10 mW laser power, 10 s acquisition time and an extended spectral range of 200 cm⁻¹ to 3200 cm⁻¹. Three spectra were acquired for each compound. The peaks are coded as follows: grey = alkyne group associated; yellow = C—C stretching; green = twisting, bending and scissoring of CH₂ and CH₃ groups; white = C O stretch; orange = C—H stretch in CH₂ groups; blue = C—H stretch in CH₃ groups. ν = stretching (s = symmetric; as = asymmetric); τ = twisting; β = bending; α = scissoring; FREO = Fermi resonance enhanced overtone of CH₂/CH₃ deformation at ca. 1440 cm⁻¹ [7,26,27,31].