The in vivo enzymatic conversions of benzaldehyde and acetyl isoeugenol in the nasal cavity. A , Total ion chromatogram of the benzaldehyde sample recovered from the nasal cavity. Upper panel, Control benzaldehyde; lower panel, the sample retrieved from the nasal cavity after perfusion. Extracted ion chromatogram of the molecular ion peak of benzoic acid (m/z 122) is shown as the inset. Peaks for benzaldehyde, benzyl alcohol, and benzoic acid are shown by arrowheads. B , Total ion chromatogram of the acetyl isoeugenol (AIEG) sample recovered from the nasal cavity. Upper panel, Control AIEG; lower panel, the sample retrieved from the nasal cavity after perfusion. Peaks for AIEG and isoeugenol (IEG) are shown by arrowheads. C , Extracted ion chromatogram of the molecular ion peaks m/z 122, 108, 106, 105, 94, and 79 of the nasal mucus sample obtained from mice that naturally inhaled benzaldehyde vapor. D , Extracted ion chromatogram of the molecular ion peak m/z 164 of the nasal mucus sample obtained from mice that naturally inhaled AIEG vapor. The samples in C and D were analyzed by GC/MS-SIM.