**5. Conclusions**

The HS-SPME/GC-MS was used to successfully quantify the amount of breath acetone in type 2 diabetes mellitus and non-diabetes patients. Blood glucose and ketone bodies were also measured. The high amount of ketone bodies (acetone, acetoacetate and beta-hydroxybutyrate) were observed in diabetic patients as opposed to non-diabetic mellitus patients. Breath acetone levels were found to increase with blood β-hydroxybutyrate and blood acetoacetate levels. This might sugges<sup>t</sup> a potential to develop breath gas analysis diagnostic tools to provide an alternative to blood testing for both type 1 and type 2 diabetes mellitus monitoring, and to assist with the prevention of diabetic ketoacidosis.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2075-4418/9/4/224/s1, Figure S1: Reconstructed GC-MS ion chromatograms (*m*/*z* 181) of patient breath samples without insulin injection (a), diabetic breath with insulin (b), and non-diabetic breath (c) sampled using on-fiber SPME derivatization with PFBHA. Figure S2: The measured breath acetone concentration by SPME GC/MS and versus blood glucose in diabetic patients.

**Author Contributions:** V.S. collected and analyzed the data and prepared the manuscript. M.B., Y.L., and B.M. contributed with reviewing, editing and, supervision with final editing of the manuscript.

**Funding:** This research was funded by [DSI-CSIR] gran<sup>t</sup> number [CHGER85x].

**Acknowledgments:** The authors would like to acknowledge Mahomedy Tasneem from Hele Joseph hospital and the patients for volunteering to be part of the study subjects.

**Conflicts of Interest:** The authors declare no conflict of interest.
