Further modifications were made to the analytical protocol to allow separation of the products of 8-oxogeranial cyclization. Concentrations of 8-oxogeranial and NADPH in the enzyme reaction were set to 0.5 and 1 mm, respectively. The injection volume was set to 1 μl and the split ratio at the GC-MS injector to 6-fold, and, after an initial hold of 5 min at 105 °C, a thermal gradient was run from 105–150 °C at a rate of 1.5 K/min and from 150–220 °C at 60 K/min with a final hold of 4 min. For quantitative comparison of spectra, they were integrated across the entire peak, and background was subtracted in AMDIS-32. Similarity was calculated with the SpectrumSimilarity function of the OrgMassSpecR package in R version 3.3.3 as the cosine of the angle between the intensity vectors.