Waterpipe smoke: a considerable source of human exposure against furanic compounds.

Smoking of waterpipes became increasingly popular in the Western hemisphere in recent years. Yet, up to now only little is known about the health hazards and on the composition of waterpipe smoke. To obtain more information on the ingredients present in waterpipe smoke we utilized two different approaches. Based on headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) instrumentation we identified new compounds present in the waterpipe smoke. Additional reversed-phase-high performance liquid chromatography-diode array detection (RP-HPLC-DAD) then led us to perform reliable quantification of the newly detected chemical species. Upon identification of a range of different furanic compounds such as 5-(hydroxymethyl)-2-furaldehyde (HMF), 2-furaldehyde, and others, we developed an easy-to-perform and fast RP-HPLC-DAD method to quantify these compounds in the complex matrix of waterpipe smoke. The detection limits range from 0.04 μg for HMF to 7.1 μg for 3-furan methanol per smoking session. Linearity, intra- and inter-day precision and recovery were determined and proved excellent. We analyzed 5 waterpipe tobacco brands and found up to 62.3±11 mg of HMF generated during one waterpipe smoking session. The applied smoking protocol comprised 171 puffs of 530 mL each and 2.6s duration every 20s. Our results reveal that waterpipe smoking constitutes a major source of HMF exposure. Furthermore, we found a distinct filter effect of the bowl water for all furanic compounds investigated except HMF.