EPA Method 500 Series Internal Std #4

Heptenophos, 100 µg/ml, Toluene, 1ml

Metformin hydrochloride, neat, Solvent-neat, Unit 1g, # of units-1, Cas.no. 1115-70-4

1,2-Dibromo-7,8-dichlorodibenzofuran, 1.2ml x 50ug/ml, toluene