Parathion-ethyl, 100 µg/ml, Toluene, 1ml

Formaldehyde-DNPH Level 4 (2ug/mL)

1,2,3,8,9-Pentachloro[13C12]dibenzo-p-dioxin, 1.2ml x 50ug/ml, toluene

EPA Method 509 Internal Standard