Targeted Characterization of the Chemical Composition of JUUL Systems Aerosol and Comparison with 3R4F Reference Cigarettes and IQOS Heat Sticks
, Patrick C. Bailey, Clarissa Yang, Bryant Hiraki, Michael J. Oldham and I. Gene Gillman *Round 1
Reviewer 1 Report
Other than the conflict of interest as all the authors are involved with the product, I do not find any other problems with the manuscript. It is for the Editor to judge whether or not this is a problem.
Author Response
Point by Point Response to Reviewer Comments and Suggestions
We would like to thank the reviewers for their comments and suggestions that have resulted in an improved manuscript.
Reviewer 1
Comment 1: Other than the conflict of interest as all the authors are involved with the product, I do not find any other problems with the manuscript. It is for the Editor to judge whether or not this is a problem.
Response: The authors appreciate the reviewer’s review of our manuscript. All of the author affiliations and funding for this study have been disclosed.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This is a good written manuscript. Authors did comprehensive analysis of the aerosol constituent cross the ENDS, cigarette, and IQOS. It would be good if authors can address some comments below:
- Authors normalized each aerosol constituent to nicotine content, however, authors did not mention the nicotine amount of each product. JUUL products contains 3% and 5% of nicotine, what the actuarial amount of nicotine? And how about the nicotine amount in 3R4F cigarettes and IQOS? If the initial nicotine content has huge difference between three type of products, should consider the analytical bias? Please explain and amend in the text accordingly.
- Authors collected the aerosols with a pad and extract the aerosols from the pad. What's the recovery of the extraction? Authors mentioned only 10 of the 53 aerosol constituents were quantifiable, did authors consider about what if the aerosols constituents were not completely extracted from the pad, therefore leads to the low levels of the aerosols constituents that were not quantifiable?
- The nicotine level in the supplementary table 3-14 were from the published journal or from the current study? If they are from the published papers, are they from the aerosols amount or the initial content?
- In the conclusion, authors mentioned the low level of HPHCs in the JUUL aerosol are likely due to the controlled temperature regulations of the JUUL, however, in the main text, authors did not give sufficient temperature related discussion.
- Please double check and re-arrange the supplementary table number, and match it in the text. There are two supplementary table 3 in current version.
Author Response
Point by Point Response to Reviewer Comments and Suggestions
We would like to thank the reviewers for their comments and suggestions that have resulted in an improved manuscript.
Reviewer 2
This is a good written manuscript. Authors did comprehensive analysis of the aerosol constituent cross the ENDS, cigarette, and IQOS. It would be good if authors can address some comments below:
Comment 1: Authors normalized each aerosol constituent to nicotine content, however, authors did not mention the nicotine amount of each product. JUUL products contains 3% and 5% of nicotine, what the actuarial amount of nicotine? And how about the nicotine amount in 3R4F cigarettes and IQOS? If the initial nicotine content has huge difference between three type of products, should consider the analytical bias? Please explain and amend in the text accordingly.
Response: In the revised manuscript we have presented the nicotine in JUUL products as a percentage and on a mass per volume basis. Since it is believed that adults adjust usage to obtain their desired amount of nicotine, results were compared on a per mg of nicotine basis.
Comment 2: Authors collected the aerosols with a pad and extract the aerosols from the pad. What's the recovery of the extraction? Authors mentioned only 10 of the 53 aerosol constituents were quantifiable, did authors consider about what if the aerosols constituents were not completely extracted from the pad, therefore leads to the low levels of the aerosols constituents that were not quantifiable?
Response: In the revised manuscript details regarding the analytical method validation have been provided as follows: “All analytical methods were validated for the analysis of ENDS aerosol according to ICH guidance Q2 (R1) with the exception of gold and carbon monoxide [41]. Method validations included an assessment of accuracy, precision, repeatability, intermediate precision, specificity, detection limit, quantitation limit, linearity and recovery from the trapping systems. All method validations were reviewed by an independent accreditation body as part of the ISO 17025 accreditation process. Carbon monoxide was determined following ISO 8454 and gold was determined by ICP-MS and method performance was verified for accuracy, detection limit, quantitation limit and linearity [42].
Comment 3: The nicotine level in the supplementary table 3-14 were from the published journal or from the current study? If they are from the published papers, are they from the aerosols amount or the initial content?
Response: In the revised supplemental material and manuscript, we have clarified that the nicotine levels are the measured aerosol amounts for the comparative products from the cited published literature.
Comment 4: In the conclusion, authors mentioned the low level of HPHCs in the JUUL aerosol are likely due to the controlled temperature regulations of the JUUL, however, in the main text, authors did not give sufficient temperature related discussion.
Response: In the revised manuscript previously published research highlighting low levels of selected HPHCs that were attributed to the temperature regulation of JUUL products has been added.
Comment 5: Please double check and re-arrange the supplementary table number, and match it in the text. There are two supplementary table 3 in current version.
Response: This has been corrected in the revised supplemental material.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Thanks for the revision.
