biostudies-literatureDavis ESNHLBI NIH HHS7459https://www.ebi.ac.uk/biostudies/studies/S-EPMC5547159biostudies-literatureUnknown7(1)In the past 5 years, e-cigarette use has been increasing rapidly, particularly in youth and young adults. Due to the novelty of e-cigarettes (e-cigs) and e-cigarette liquids (e-liquids), research on their chemo-physical properties is still in its infancy. Here, we describe a previously unknown and potentially useful property of e-liquids, namely their autofluorescence. We performed an emission scan at 9 excitation wavelengths common to fluorescent microscopy and found (i) that autofluorescence differs widely between e-liquids, (ii) that e-liquids are most fluorescent in the UV range (between 350 and 405?nm) and (iii) fluorescence intensity wanes as the emission wavelength increases. Furthermore, we used the autofluorescence of e-liquids as a marker for tracking e-cig aerosol deposition in the laboratory. Using linear regression analysis, we were able to quantify the deposition of a "vaped" e-liquid onto hard surfaces. Using this technique, we found that every 70?mL puff of an e-cigarette deposited 0.019% e-liquid (v/v) in a controlled environment. Finally, we vaped a surface in the laboratory and used our method to detect e-cig aerosol third-hand exposure. In conclusion, our data suggest that e-cigarette autofluorescence can be used as a marker of e-cigarette deposition.Scientific reportsE-Liquid Autofluorescence can be used as a Marker of Vaping Deposition and Third-Hand Vape Exposure.PMC5547159P50 HL120100Goodell HTarran RSassano MFDavis ESfalseE-Liquid Autofluorescence can be used as a Marker of Vaping Deposition and Third-Hand Vape Exposure.In the past 5 years, e-cigarette use has been increasing rapidly, particularly in youth and young adults. Due to the novelty of e-cigarettes (e-cigs) and e-cigarette liquids (e-liquids), research on their chemo-physical properties is still in its infancy. Here, we describe a previously unknown and potentially useful property of e-liquids, namely their autofluorescence. We performed an emission scan at 9 excitation wavelengths common to fluorescent microscopy and found (i) that autofluorescence differs widely between e-liquids, (ii) that e-liquids are most fluorescent in the UV range (between 350 and 405?nm) and (iii) fluorescence intensity wanes as the emission wavelength increases. Furthermore, we used the autofluorescence of e-liquids as a marker for tracking e-cig aerosol deposition in the laboratory. Using linear regression analysis, we were able to quantify the deposition of a "vaped" e-liquid onto hard surfaces. Using this technique, we found that every 70?mL puff of an e-cigarette deposited 0.019% e-liquid (v/v) in a controlled environment. Finally, we vaped a surface in the laboratory and used our method to detect e-cig aerosol third-hand exposure. In conclusion, our data suggest that e-cigarette autofluorescence can be used as a marker of e-cigarette deposition.2017-01-01T00:00:00Z2017 Aug2021-02-20T14:32:52Z2019-03-27T02:52:54ZS-EPMC55471592878507210.1038/s41598-017-07862-w