E-Cigarette Quality Control: Impurity and Nicotine Level Analysis in Electronic Cigarette Refill Liquids

Table 1

Amount of impurities related to the degradation of nicotine and unidentified impurities expressed as a percentage of the nicotine content.

Sample	Impurities (%)∗								Total
	Cotinine	Nornicotine	Anatabine	Myosmine	Anabasine	Beta-nicotyrine	Nicotine N-oxide	Unknown impurities
S1		0.48	0.72	0.17		0.1		24.5	25.97
S2	0.46	8.8		1.47			0.33	12.5	23.56
S3									0
S4				0.33			0.36	1.2	1.89
S5	0.33							0.2	0.53
S6	1.21							1.2	2.41
S7					0.4			1.98	2.38
S8								0.4	0.4
S9									0
S10								1.1	1.1
S11									0
S12	0.1	0.45		0.24		0.06	0.3	10.1	11.25
S13	0.09	0.3			0.4	0.1	0.22	2.7	3.81
S14	0.7		0.32	0.56	0.23		0.16	1.8	3.77
S15		2.83		1.01				1.3	5.14
S16	1.49			1.2	1.83	0.5		15.4	20.42
S17								6.2	6.2
S18	1.68	0.86	0.23					20.6	23.37
S19	1.23	0.72	0.27	0.2			0.06	30.1	32.58
S20	1		0.76		1.48			19.2	22.44
S21		0.16						7.4	7.56
S22	0.24		0.18	0.34	0.23		0.08	1.6	2.67
S23	0.35	0.12		0.32			0.24	2.1	3.13
S24	1.12		0.45	0.21			0.08	1.1	2.96
S25		0.14	0.32		0.3			0.4	1.16
S26	0.8	0.12	0.8			0.1	0.3	0.67	2.79
S27	0.5		0.06		0.3			1.3	2.16
S28	0.05				0.07				0.12
S29		0.15					0.12	0.23	0.5
S30	0.65	0.13				0.2		0.12	1.1
S31				0.33			0.16	1.2	1.69
S32	0.31				0.08			0.2	0.59

Impurity rate expressed in percentage of nicotine content.