Analysis of Vaporizers, E-Cigarettes, and other ENDS

ENDS Analysis

In the meantime we have advanced the experimental setup to perfection and offer it as an all-in-one solution:

• Mainstream aerosol analysis: Common commercially available smoking machines can be connected to our setup in order to precisely control puff duration, volume and frequency for subsequent online PTR-TOFMS analysis and real-time quantification.
• Adjustable dynamic range: IONICONs professional dilution system enables shifting the dynamic range of the PTR-TOFMS instrument by four orders of magnitude, so that even extremely high concentrations in the ENDS mainstream aerosol can be investigated in absence of any saturation effects.
• Exhaled breath analysis: Relatively high compound concentrations in exhaled breath after mouth-hold maneuvers as well as very low concentrations following inhalation of ENDS aerosol can be quantified with a split-second time resolution utilizing the novel ENDS breath analysis interface for PTR-TOF.
• Focus exclusively on the particle-phase: IONICON's genuine CHARON particle inlet coupled to our purpose-built iso-kinetic 1000-fold dilution system allows for a quantitative and direct characterization of main-stream particles of ENDS.
• True puff-by-puff investigations: In contrast to established offline methods we offer true puff-by-puff analysis for mainstream and exhaled breath investigations.

All surfaces that come into contact with the sample air are heated (no cold-spots) and treated according to our innovative EVR standards.

Unique ionization modes

Seize maximum information with IONICON's unique ion-chemistry

IONICON is world-renowned for manufacturing PTR-TOFMS instruments with controllable and well-defined ion-chemistry (see patents EP3309817B1, US10074531B2). Particularly in the field of ENDS analysis this is a crucial requirement.

In all of our PTR-TOFMS instruments, i.e. even in those equipped with sensitivity boosting RF devices (ion funnel, hexapole ion guide), the reduced electric field strength E/N can be precisely controlled and adjusted to the specific needs of the experiment. This is of utmost importance for dealing with "fragile" molecules like propylene glycol (PG) and vegetable glycerol (VG).

Extensive tests with different types of ENDS have shown that in addition to the established H₃O⁺ also NO⁺ and, most importantly, NH₄⁺ reagent ions, which are produced without the need of any toxic and corrosive ammonia with IONICON's exclusive method, are essential for investigating the full chemical picture. In all of our PTR-TOFMS instruments reagent ions can be rapidly switched between H₃O⁺, NO⁺ and NH₄⁺ with the SRI option.

Real-time exhaled breath analysis

Maximum hygiene and no memory effects with our dedicated breath sampling interface

Most existing online breath sampling interfaces for analytical instrumentation aim at buffering of exhaled breath samples in order to extend the time available for analysis. This is the exact opposite of what is required for exhaled breath analysis following ENDS use: split-second time resolved compound quantification during exhalation while getting rid of sticky compounds in the system as soon as the exhalation process has finished.

We at IONICON have developed a dedicated breath sampling interface, which can be directly connected to our PTR-TOFMS instruments for online quantification in real-time. Carefully selected materials in combination with a cold-spot free design prevent accumulation of undesirable signal background. Disposable mouth-pieces with an integrated "non-return valve" fulfill common hygiene standards and enable studies with a large number of participants in very short time periods.

High compound concentrations in the exhaled breath after a mouth-hold maneuver (no inhalation) do not cause saturation effects in the ultra-sensitive PTR-TOFMS instrument because of the integrated dilution solution, which is fully electronically controlled via the PTR-TOFMS control software.

Absolute quantification accuracy

Convenient calibration with the IONICON LCU

PTR-TOFMS provides absolute quantitative analysis in real-time. However, to obtain high accuracy concentration values, rapid and easy-to-use calibration of certain compounds in e-liquids can be very handy. Particularly, the main components of e-liquids, PG and VG, tend to fragment upon ionization via proton transfer from H₃O⁺. Although relative concentration measurement results (e.g. puff-by-puff variations) are not affected by this phenomenon, absolute concentration values should be corrected for the fragmentation ratios.

With IONICON's Liquid Calibration Unit (LCU) liquid standards are brought into the gas phase at well-defined concentrations for direct analysis with a PTR-TOFMS instrument. There is no need to purchase expensive liquid standards, but the user can easily mix home-made standards by dissolving defined amounts of pure substances in water or hexane.

Because of full automation of the LCU and the PTR-TOFMS control software, calibration curves can be acquired without the user being present during the measurement, thus saving valuable working hours. In addition to correcting the concentration values of PG and VG, with the LCU also the accuracy of all other important constituents (e.g. nicotine, flavor and aroma compounds, etc.) can be brought to perfection.