Surprise! Do it yourself e-cig flavors often have undisclosed nicotine

Pru Talbot and her colleages at UC Riverside just published an important paper, "Unexpected nicotine in do-it-yourself electronic cigarette flavourings" in Tobacco Control.  The title says it all.
 
The bottom line of the paper is:

 
The current finding of nicotine in DIY flavouring products that are expected to be nicotine free and our prior finding that a DIY bottle of nicotine (134.7 mg/mL) was unlabelled, are important public health problems. These products, which are presented to the consumer as ‘nicotine free’ (http://www.tastypuff.com/product/joosy-froot/), could lead to unwanted addiction, poisoning, or even death.

They go on to recommend

The simplest solution to this problem would be, at minimum, to require that any products containing nicotine be clearly labelled with the term ‘nicotine’ and an accurate concentration. Consumers who wish to use 0% nicotine products could then avoid unwanted exposure and EC users could protect their children from accidental ingestion of nicotine. The demonstration of nicotine in presumably nicotine-free DIY flavouring solutions should be valuable information for regulatory agencies,  physicians, EC users and poison control centres.

They are too polite to stress another point:  It is in the interest of e-cigarette sellers to spike their products with the addictive drug nicotine to ensure customer loyalty.
 
Another important implication is that policymakers should not believe claims that some e-cigs do not contain nicotine.
 
The full citation for the paper is: Davis B, Razo A, Nothnagel E, et al. Unexpected nicotine in do-it-yourself electronic cigarette flavourings. Tob Control Published Online First: 27 July 2015 doi:10.1136/tobaccocontrol-2015-052468.