Potassium (K)

1,2,3,4,6,9-Hexachloro[13C12]dibenzofuran, 1.2ml x 50ug/ml, toluene

PCB 153, 10.0 µg/ml, Isooctane, 10ml

Ethiofencarb-sulfoxide, 100 µg/ml, Acetonitrile,