Infra-red spectroscopy is a relatively inexpensive and high sensitivity tool for chemical analysis. In examining biological samples however it is severely limited by spectral resolution. Specifically the width of individual vibrational modes exceeds the difference between the modes preventing the analysis of individual residues. It is exactly this sort of information that may turn FTRI into a high resolution technique. One approach that has been used to overcome this limitation is isotopic labeling. In my lecture I will present strategies for labeling including the synthesis of new labeled groups such as the peptidic 1-13C=18O. I will also cover what sort of information it may be possible to retrieve from such labels, exemplifying their utility.