Vials used were of volume 4 mL (clear vial with screw top and a hole cap with PTFE/silicone septa #27136, SUPELCO Inc., Bellefonte, Pa., U.S.A.) for solid-phase micro-extraction-gas chromatography-mass spectrometer (SPMEGC/MS) analysis and 10 mL (clear vial and a tin hole cap with PTFE/silicone septa #27300, SUPELCO Inc.) for electronic nose analysis.