Ethanol in serum control EtOH SE (0.5g/L), 10x3ml

2,2',3,3',4,5,5'-Heptachloro-4'-methoxy[13C12]biphenyl, 1.2ml x 50ug/ml, toluene

Endosulfan II

4-Ethylcatechol, 100 µg/ml, Methanol, 10ml