2,3,7,8-TetraCDD 10 ng/mL 1,2,3,4,7,8,9-HeptaCDF (W.D.) . 25 ng/mL2,3,7,8-TetraCDF . 10 ng/mL OctaCDD 50 ng/mL1,2,3,7,8-PentaCDD25ng/mL OctaCDF 50 ng/mL1,2,3,7,8-PentaCDF . 25 ng/mL 2,3,7,8-TetraCDD (13C12,99%) . 50 ng/mL2,3,4,7,8-PentaCDF . 25 ng/mL 2,