Similarly to Fig. 3b, Fig. 4b presents the data points of the seven Scenedesmus and eleven Chlorella samples. The linear regression lines now show a better correlation to the entire microalgae data set. This supports the above hypothesis that different carbohydrate compositions in different microalgae strains have an effect on the correlation of the two techniques. For this purpose it would be beneficial to investigate the structural composition of the carbohydrate fraction of the microalgae samples and compare the pyrolysis products. This could lead to a more accurate overall linear relation for any microalgae sample but also potentially shed light on the carbohydrate composition of microalgae by simply investigating the pyrolysis products. For the separate linear regression lines the R2 values increase from 0.6 to 0.85–0.91 which represents a very good correlation of the two analysis techniques.