A reverse-phase HPLC method to detect and quantify levels of hopanoids in bacteria has been developed. Chromophores have been introduced by derivatization and the levels of the C35 hopanoids and their conjugates can be measured in bacterial lipid extracts down to picomole levels. Some structural variations of the complex lipids were detected after derivatization and were easily purified using the same HPLC system. Zymomonas mobilis and Rhodospirillum rubrum extracts were examined using this system and different structural examples of the lipids were detected. The relative levels of the different triterpenes were very dependent on the growth conditions.