February 20, 2017

Certified Reference Material Being Used to Improve E-Liquid Quality

Independent quality checks have been conducted for e-liquids to confirm what is written on labels, whether it is the same as what was written in samples. Researchers have answers that help paint a better picture of the future issues for e-liquids.

American based researchers from three institutions came together to analyze e-liquid and vapors so that they could determine a way to improve e-liquid quality. These researchers from the UN University of Maryland College Park, Johns Hopkins University Baltimore, and the University of Maryland Baltimore, Johns Hopkins University Baltimore and the University of Maryland College Park have all sided for the establishment of standards in e-liquid production. Furthermore, they have argued in favor of a certified reference material, CRM.

The British Standards Institution (BSI) and the Association Française de Normalisation (AFNOR), have such standards which state that e-liquids must be composed of a well-defined recipe with specific ingredients mixed in accordance with industry protocols. In hopes of bringing some of those standards to the United States, these researchers have tested different e-liquid for impurities, stability, and the concentration of nicotine. They vaporized the liquids and analyzed the outcomes.

For the analysis, they used techniques including the Gas Chromatography Mass spectrometry (GC-MS) for organic compounds. For the physical vapor measurements they used particle sizing (Aerodynamical Particle Sizer). For metals and particle size, they used Inductively Coupled Plasma – Optical Emission Spectrometry (ICP – OES).

Another aspect of the article describes how to generate the vapor they analyzed using different techniques. There were a handful of measures performed on the e-liquid and the vapors. They include the following:

 Homogeneity tests on the reference e-liquids

 Stability tests on the reference e-liquids

 Detection of metals in the reference e-liquids

 Chemical characterization of vapor generated by the e-liquids

 Physical properties of the reference vapor

 Presence of metals in the vapor

This chemical characterization is most relevant for e-cigarette users and requires further discussion. The measurement here consisted of 16 chemicals potentially present in the e-liquids, 7 of which are considered “dangerous chemicals” and 5 of which have warning labels. Note that a lot of these are only dangerous if ingested in a normal form, not inhaled.

There were 16 ingredients screened in e-liquids and their vapor including:

 1-(p- Toluidino)-1- deoxy-beta- d-idopyranose

 4-Pyridinecarboxaldehyde,

 Nicotine,

 Nicotyrine,

 Propylene Glycol,

 2,4,7-trimethyl- 1,

 8-naphthyridine,

 1-Butanol,

 Cotinine,

 5-Methyl- 2-heptanol,

 3-(3,4- dihydro-2H- pyrrol-5- yl) pyridine (Myosmine)

 1-(4- pyridinylmethyl)-1H- pyrazol-5- amine,

 2,3-dihydro- 1H-inden- 1-one (Indanone),

 2-methyl 2-pentanol (Dimethylbutanol),

 3-Ethyl- 5-hexen- 3-ol,

 6-Methyl- 1,2,3,4-tetrahydroquinoline

These authors explained that they noticed color change in the e-liquid after one week, something they attributed to the oxidation of nicotine without actually confirming this. The alleged aging of the e-liquid requires further study to be confirmed. After all, simple color change does not necessarily mean something is wrong, or that the toxicity of the product has increased because of different chemical reactions. In fact, some users steep their e-liquids to remove certain harsher flavors associated with the liquid nicotine.

The authors at least discussed the fact that there would need to be a new cross comparison between different laboratories, different protocols, and a blank measurement for comparisons. After all, without this additional research on e-cigarettes, the industry cannot improve upon its existing product. Improvement is the goal of any product, by it cigarettes, food, or something tangible for the home.

More Questions than Answers

Now this leaves more questions than answers. How often does the coil need to be changed? What heating elements are safer? What impact do additives have once e-liquid is vaporized? How can the overall safety be improved? How long can e-liquids be kept in a tank, or cartomizer, or even a plastic bottle?

Those are just a handful of the many questions that should be answered quickly, and one day once the science behind e-liquid is mature, answers might be more readily provided and fear will no longer be the dish of the day. As it stands, the industry and media surrounding the industry seeks to paint a bleak picture where really, there is a developing one.

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