Fig. 1

Gas chromatography assay of odorants in the control solution. Detection voltages were plotted against retention time. The chemical structures of the odorants used are indicated in the figures. Arrows indicate the peak of dissolved molecules. a Alcohol. C4; 10 mM (black), 1 mM (red), 0.1 mM (blue). C6; 10 mM (black), 1 mM (red), 0.1 mM (black). C8; 2.7 mM (black), 0.9 mM (red), 0.07 mM (blue), 0.007 mM (green). b Ester. C4; 10 mM (black), 1 mM (red), 0.1 mM (blue). C6; 10 mM (black), 1 mM (red), 0.1 mM (blue). C8; 2.1 mM (black), 0.8 mM (red), 0.08 mM (blue). c Carboxylic acid. C4; 10 mM (black), 1 mM (red), 0.1 mM (blue). C6; 10 mM (black), 1 mM (red), 0.1 mM (blue). C8; 2.5 mM (black), 0.8 mM (red), 0.08 mM (blue)