Table 4. List of Some of the Impurities Identified in the pH 10.5 Extract of Methamphetamine Synthesized by the Reductive Amination Route^a.

no.	RT	impurity extracted at pH 10.5	semiquantitative concentration mg/mL	intra-batch (n = 6) RSD	inter-batch (n = 20) RSD
1	7.034	Acetic acid	6 × 10−3	55%	179%
2	9.408	Amphetamine	5 × 10−2	49%	119%
3	10.715	N-(1-Methyl-2-phenylethylidene)methenamine	5 × 10−1	15%	52%
4	11.06	Dimethylamphetamine (DMA)	3 × 10−2	53%	98%
5	13.664	N-Formylamphetamine	3 × 10−3	106%	109%
6	14.445	Bibenzyl	6 × 10−3	144%	112%
7	14.584	N-Formylmethamphetamine*	2 × 10−2	103%	77%
8	15.034	N-Acetylmethamphetamine*	2 × 10−2	93%	142%
9	16.289	Dibenzylketone*	1 × 10−3	100%	196%
10	17.92	3,4-Diphenyl-3-buten-2-one*	7 × 10−3	166%	154%
11	18.014	α-Benzyl-N-methylphenethylamine*	8 × 10−4	129%	164%
12	18.119	Benzylmethamphetamine	2 × 10−3	138%	162%
13	18.192	3,4-Diphenyl-3-buten-2-one*	4 × 10−3	131%	129%
14	18.453	N-β-(Phenylisopropyl)benzyl methyl ketimine*	6 × 10−2	64%	77%
15	18.83	N-Methyldiphenethylamine*	2 × 10−3	120%	153%
16	20.189	N-Benzoylamphetamine	4 × 10−3	51%	82%
17	20.409	N-Benzoylmethamphetamine	1 × 10−2	92%	118%
18	21.046	2,6-Dimethyl-3,5-diphenylpyridine*	3 × 10−2	82%	173%
19	21.214	Pyridine 7 and 14*	2 × 10−2	76%	65%
20	22.385	N,N-Di-(β-phenylisopropyl)formamide	5 × 10−3	113%	89%
21	23.253	N-Methyl-N-(1-methyl-2-phenylethyl)-2-phenylacetamide*	4 × 10−3	87%	108%

^aRSDs were calculated using peak areas normalized to the sum of the CHAMP target impurities present in the relevant chromatogram. Route specific impurities for the reductive amination route are not present in the basic extract. CHAMP target impurities are marked with an asterisk (*).