Confirmation of heptachlor epoxide and octachlor epoxide in milk via fused silica gas chromatography/negative ion chemical ionization mass spectrometry

A method for the mass spectral confirmation of heptachlor epoxide and octachlor epoxide in milk is described. The method includes the use of a 30 m × 0.25 mm DB‐1701 fused silica gas chromatography column combined with negative ion chemical ionization mass spectrometry. By using this technique, confirmation of these compounds in milk can be performed at a level of 0.1 parts‐per‐million in milk fat.