Custom Mixture of saturated biomarker hydrocarbons 3 components, each 12,5µg/mL in isooctane 0609.29 alpha alpha alpha (20R,24R)-24-Ethylcholestane 1321.29 17 alpha(H),21ß(H)-30-Norhopane 0132.30 17 alpha(H),21ß(H)-Hopane