Table 5.
Comparison of methodologies and concentrations for nicotine-related alkaloids in (A) E-liquids and (B) electronic cigarette (ECIG)-generated aerosol of the current study compared with other studies.
| A. NRAs in E-liquids | |||||||||||
| Study | E-Liquid Brand | Extraction Process | Measured by | Nornicotine | Contine | Anabasine | Anatabine | Myosmine | |||
| Current Study | Various refill solutions | 420 µL of E-liquid diluted in 10 mL of methanol | HPLC-PDA | 5-21 | BDL-15 | µg/mL BDL-66 | 15-835 | 3-37 | |||
| Trehy et al. [9] | Various cartridges | Cartridge pad diluted in 50 mL of Methanol | HPLC-PDA | NA | BDL | µg/cartridge BDL | BDL-0.8 | <LOQ-0.1 | |||
| Etter et al. [12] | Various refill solutions | Dilution with 1 M ammonia | GC-MS or GC-flame ionization | BDL-15 | BDL-39 | µg/mLBDL-83 | BDL-374 | BDL-77 | |||
| Liu et al. [17] | Laboratory Reference E-liquid | 1 to 10 dilution in 100 mM ammonium acetate | LC-MS/MS | 5 | 31 | µg/g BDL | 23 | 6 | |||
| Flora et al. [34] | Various Cartridges and refill Solutions | Dilution with 70% Methanol | LC-MS | <48 | <48 | µg/mL #<48 | <144 | <48 | |||
| B. NRAs in ECIG-generated aerosol | |||||||||||
| Study | Puff Volume (mL) | Number of Puffs | Puff /Interval (s) | BatteryPower (W) | Extraction Process | Measured by | Nornicotine | Contine | Anabasine | Anatabine | Myosmine |
| Current Study | 33.6 | 45 | 5/10 | 5.7 | Methanol extraction from a glass fiber disk | HPLC-PDA | BDL | 16 | µg/mL @ 8 | 17 | 14 |
| Trehy et al. [9] | 100 | 30 | ?/60 | ? | 10% acetonitrile in water using an impinge | HPLC-PDA | NA | BDL | µg/cartridge BDL | <LOQ | BDL |
| Margham et al. [16] | 55 | 200 | 3/30 | 4.5 | ammonium acetate extraction from glass fiber disk * | HPLC-MS/MS | BDL | 1 | µg/collection <LOQ | <LOQ | 3 |
| Liu et al. [17] | 55 | 50 | 3/30 | 5 | ammonium acetate extraction from glass fiber disk * | HPLC-MS/MS | 0.9 | NA | µg/collection 2.1 | 6.0 | <LOQ |
| Flora et al. [34] | 55 | 100 | 4/30 | ? | extraction from glass fiber disk | LC-MS | <45-53 | <49 | µg/mL ! <38-44 | 128-138 | <47 |
NA = not available; BDL = below detection limit or <LOD; ? = information not specified: * = used CORESTA methods [37]; # = Concentrations calculated from % of nicotine and assumed nicotine in the cartridges and refill solutions is 24 mg/ml; @ = Concentrations given are based on 100% recovery of the reference E-liquid in the current study; ! = concentrations given are based off transfer efficiencies from the concentrations already specified in part A of this table.