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

Table 2

Comparison of labeled and determined nicotine concentrations in 32 commercial liquids of e-cigarette (n = 32).

Sample	Country origin	Liquid flavor	Labeled nicotine concentration (mg/mL)	Founded nicotine concentration (mg/mL) mean ± SD (n = 3)	Relative difference (%)	Significant difference ()
S1	USA	Tobacco	6	3.8	−36.67	Yes
S2	USA	Cookies	12	11.2	−6.67	Yes
S3	USA	Cherry	3	0	−100.00	Yes
S4	France	Blueberry	6	5.94	−1.00	No
S5	France	Strawberry	12	11.75	−2.08	No
S6	France	Mint	12	9.3	−22.50	Yes
S7	Spain	Fruit juice	3	2.91	−3.00	No
S8	France	Apple mint	6	5.4	−10.00	Yes
S9	USA	Honey	3	0	−100.00	Yes
S10	Germany	Strawberry	6	3.7	−38.33	Yes
S11	France	Coffee	12	4.1	−65.83	Yes
S12	USA	Green apple	6	5.9	−1.67	No
S13	France	Raspberry	6	2.2	−63.33	Yes
S14	USA	Strawberry	24	20.5	−14.58	Yes
S15	—	Mint	3	0.3	−90.00	Yes
S16	France	Tobacco	6	5.92	−1.33	No
S17	Spain	Honey	3	3.1	3.33	No
S18	—	Strawberry	6	1.6	−73.33	Yes
S19	France	Cherry	11	10.9	−0.91	No
S20	USA	Menthol	12	11.1	−7.50	Yes
S21	China	Banana	6	5.8	−3.33	No
S22	UK	Tobacco	3	0.2	−93.33	Yes
S23	France	Orange	12	9.1	−24.17	Yes
S24	China	Cookies	6	2.3	−61.67	Yes
S25	USA	Orange	11	10.5	−4.55	No
S26	USA	Blueberry	3	2.96	−1.33	No
S27	Germany	Strawberry	12	8.9	−25.83	Yes
S28	Belgium	Tobacco	6	5.5	−8.33	Yes
S29	China	Fruit juice	3	2.2	−26.67	Yes
S30	France	Green tea	6	5.6	−6.67	Yes
S31	China	Honey	3	2.1	−30.00	Yes
S32	USA	Tobacco	6	5.2	−13.33	Yes

Statistical significant difference () between mentioned and detected nicotine level by t-test.