Table 3. Method Validation for Quantitating Terpenoids and Nicotine in e-Juices by Headspace GC–MSa.
| limitb |
recovery
(%)c |
RSD
(%) |
||||||
|---|---|---|---|---|---|---|---|---|
| ID | analyte | MDL | MRL | low | mid | high | intraday | interday |
| 1 | α-pinene | 0.04 | 5.00 | 105 | 94.6 | 101 | 2.64 | 4.86 |
| 2 | camphene | 0.05 | 5.00 | 104 | 94.2 | 99.9 | 2.16 | 4.35 |
| 3 | β-myrcene | 0.13 | 5.00 | 99.7 | 95.9 | 99.1 | 1.78 | 2.84 |
| 4 | (−)-β-pinene | 0.22 | 5.00 | 105 | 99.0 | 104 | 2.24 | 4.04 |
| 5 | δ-3-carene | 0.16 | 5.00 | 105 | 98.8 | 104 | 2.08 | 3.97 |
| 6 | α-terpinene | 0.13 | 5.00 | 101 | 94.7 | 99.6 | 1.91 | 4.01 |
| 7 | cis-β-ocimene | 0.77 | 5.00 | 102 | 97.2 | 99.0 | 2.44 | 2.40 |
| 8 | (+)-limonene | 0.12 | 5.00 | 98.7 | 94.8 | 99.2 | 2.36 | 3.58 |
| 9 | p-cymene | 0.10 | 5.00 | 100 | 94.2 | 99.6 | 2.59 | 4.15 |
| 10 | trans-β-ocimene | 0.62 | 5.00 | 99.0 | 94.3 | 98.5 | 2.36 | 3.49 |
| 11 | 8-cineole (eucalyptol) | 0.18 | 5.00 | 101 | 95.3 | 98.6 | 1.81 | 2.91 |
| 12 | γ-terpinene | 0.16 | 5.00 | 101 | 94.4 | 99.3 | 2.26 | 3.82 |
| 13 | terpinolene | 0.33 | 5.00 | 105 | 97.8 | 102 | 2.21 | 3.66 |
| 14 | cis-linalool oxide | 0.59 | 5.00 | 104 | 96.5 | 99.3 | 3.01 | 2.78 |
| 15 | trans-linalool oxide | 1.83 | 5.00 | 105 | 102 | 104 | 3.02 | 2.49 |
| 16 | linalool | 1.35 | 10.0 | 101 | 95.7 | 97.0 | 2.65 | 2.18 |
| 17 | (−)-isopulegol | 0.35 | 5.00 | 101 | 96.2 | 98.2 | 3.18 | 2.52 |
| 18 | α-terpineol | 0.53 | 5.00 | 97.3 | 93.2 | 96.7 | 3.81 | 3.65 |
| 19 | citronellol | 2.54 | 10.0 | 97.8 | 95.3 | 94.7 | 2.69 | 2.83 |
| 20 | nerol | 0.69 | 5.00 | 96.5 | 96.1 | 99.4 | 3.61 | 3.49 |
| 21 | geraniol | 1.66 | 10.0 | 104 | 91.3 | 96.0 | 4.72 | 4.61 |
| 22 | β-damascenone | 0.67 | 5.00 | 98.3 | 103 | 103 | 1.74 | 1.82 |
| 23 | β-caryophyllene | 0.50 | 5.00 | 103 | 95.5 | 101 | 1.87 | 4.31 |
| 24 | β-damascone | 0.63 | 5.00 | 95.7 | 94.2 | 95.6 | 1.54 | 2.30 |
| 25 | α-humulene | 0.74 | 5.00 | 105 | 96.5 | 101 | 1.56 | 3.86 |
| 26 | cis-nerolidol | 1.58 | 10.0 | 100 | 96.2 | 98.3 | 2.13 | 2.11 |
| 27 | trans-nerolidol | 0.41 | 5.00 | 100 | 93.7 | 96.9 | 1.97 | 2.95 |
| 28 | (−)-guaiol | 0.39 | 5.00 | 94.6 | 89.0 | 93.3 | 0.92 | 3.58 |
| 29 | (−)-caryophyllene oxide | 0.33 | 5.00 | 97.8 | 97.8 | 97.3 | 2.08 | 2.14 |
| 30 | (−)-α-bisabolol | 0.96 | 5.00 | 101 | 96.0 | 97.5 | 1.34 | 2.15 |
| 31 | nicotine | 0.05 | 0.50 | 94.3 | 101 | 102 | 3.53 | 2.71 |
a
Concentrations are presented based on e-juice volume. MDL: method detection limit. MRL: method reporting limit. The calibration ranges for terpenoids were from 1 to 300 ppm (10–3000 ppb in the vial), except for trans-β-ocimene, linalool, citronellol, and geraniol (5–300 ppm, or 50–3000 ppb in the vial). The calibration range for nicotine was from 0.25 to 30 mg/mL (2.5–300 μg/mL in the vial).
b
Unit: ppm for terpenoids, and mg/mL for nicotine.
c
Concentration: Low-, mid-, and high-level concentrations for terpenoids are 10, 75, and 250 ppm, respectively. Low-, mid-, and high-level concentrations for nicotine are 1, 7.5, and 25 mg/mL, respectively.