Custom mix of C9-C19 aromatic compounds 1273.9 1-Ethyl-3-methylbenzene – 250µg/mL 1272.9 1-Ethyl-4-methylbenzene – 250µg/mL 1269.9 1,3,5-Trimethylbenzene – 250µg/mL 2156.9 2-Ethyl-1-methylbenzene – 250µg/mL 1270.9 1,2,4-Trimethylbenzene – 250µg