Potential reason for presence as impurity or additive Frequency of occurrence No (%) Impurity found
Used in the production of MA using P2P 50 (94.34) Acetic acid
Intermediate reagent in the production of MA by the Leuckart or reductive amination methods 25 (47.17) Phenyl-2-propanone
Conversion of ephedrine to phenmetrazine at GC high temperature   11 (20.75) Phenmetrazine
Cutting agent in the production of ATS 10 (18.87) N,N-Dimethylamphetamine
Indicative of Leuckart route used for MA production
Used as precursor in MA synthesis 10 (18.87) Pseudoephedrine
An intermediate in MA synthesis procedure from ephedrine and pseudoephedrine by Emde and Nagai methods 9 (16.98) 1,2-dimethyl-3-phenylaziridine
Starting material in the synthesis of 5 (9.43) Benzaldehyde
P2P
Deliberately added active pharmaceutical ingredient 5 (9.43) Tramadol
Product of Nagai method, product of MA precipitation using acetic moiety 3 (5.67) N-acetylmethamphetamine
Overlapping with areas of MA synthesis 2 (3.77) Ecstasy
Produced as incomplete hydrolysis of MA in Leuckart reaction 1 (1.89) N-Formylmethamphetamine
An intermediate in MA synthesis procedure from ephedrine and pseudoephedrine by Emde and Nagai methods 1 (1.89) N-Benzyl 2-methylaziridine
ATS= Amphetamine- type stimulants; MA= Methamphetamine; P2P= Phenyl-2-propanone
Table 1: Impurities, frequency of their occurrence and the reason for their presence in seized methamphetamine samples, Kermanshah, Iran.