Table 1. Intensities of Chromatographic Peaks for Chemicals Spiked in the Road Dust Sample^a.

	n-nonanal	2,6-dimethylphenol	2-ethylhexanoic acid	2,6-dimethylaniline	methyl dodecanoate
retention time (min)	4.24	4.77	4.91	5.55	12.13
concentration in the chemical-spiked road dust sample (μg mL–1)	15.8	12.8	15.2	12.8	16.4
I. Peak height in the road dust sampleb	7.1 × 106	1.7 × 107	2.4 × 106	3.7 × 106	5.6 × 106
II. Peak height in the chemical-spiked road dust sample	6.4 × 106	2.3 × 107	9.6 × 106	1.1 × 107	3.8 × 107
ratio (II/I)	0.90	1.32	4.04	3.06	6.80
remarks	with overlapped peak	with overlapped peak	no remarkable overlapped peak	no remarkable overlapped peak	no remarkable overlapped peak

^aThe intensities of the chromatographic peaks were calculated based on the total ion chromatogram (Figure 1).

^bPeaks eluted at the same positions as the respective chemicals were alternatively used for the intensity calculation.