The european pharmacopoeia/ICH Class 2 mix A consists of 13 components they are, chlorobenzene (360 μg/ml), cyclohexane (3,880 μg/ml), cis-1,2-dichloroethene (1,870 μg/ml), dichloromethane (600 μg/ml), n,n-dimethylformamide (880 μg/ml), ethylbenzene (369 μg/ml), n-hexane (290 μg/ml), methylcyclohexane (1180 μg/ml), toluene (890 μg/ml), 1,1,2-trichloroethene (80 μg/ml), m-xylene (1,302 μg/ml), o-xylene (195 μg/ml) and p-xylene (304 μg/ml).