Fig. 1

UPLC–MS profiles of the surfactin standard (a); ST34 Fructose-MSM extract (b); ST34 Diesel-MSM extract (c). The top row profiles depict the signal of positive molecular ions detected between 10 and 13 min. Note the difference in Y axis which are a direct indication of amounts. The profiles below each top row spectrum show the extracted spectra of the four surfactin groups with Srf1 = m/z 994.65, Srf2 = m/z 1008.66; Srf3 = m/z 1022.68 and Srf4 = m/z 1036