Content Handbook O

Outline of method

The sample of pirimiphos-methyl technical material is dissolved in acetone, containing an internal standard, and the pirimiphos-methyl content determined by capillary gas chromatography.

Scope

The method is usable for TC, EC and CS formulations.

Impurities

Iso-pirimiphos-methyl

Outline of method

Iso-pirimiphos-methyl (O-2-diethylamino-6-methylpyrimidin-4-yl O,S-dimethyl phosphorothioate) is determined along with pirimiphos-methyl, but due to the instability of iso-pirimiphos-methyl its content is calculated using the response factor of pirimiphos-methyl.

Other relevant impurities

O,O-dimethyl phosphorochloridothioate (DMPCT)
O,O,O-trimethyl phosphorothioate (MeOOOPS)
O,O,S-trimethyl phosphorothioate (MeOOSPO)
O,O,S-trimethyl phosphorodithioate (MeOOSPS)

Outline of method

DMPCT MeOOOPS, MeOOSPO and MeOOSPS are determined relative to the active ingredient by capillary gas chromatography-mass spectrometry with 4,4-dimethoxybenzophenone as internal standard, applying the standard addition mode.