Selective ionization of 2,4-xylenol in mass spectrometry using a tunable laser and supersonic jet technique.

A supersonic jet/resonance-enhanced multiphoton ionization/time-of-flight mass spectrum (SSJ/REMPI/TOF-MS) was measured for xylenols and ethylphenols. Sharp and intense peaks were observed in the REMPI spectrum of 2,4-xylenol, and the wavelength of the peak tentatively assigned to the 0-0 transition was the longest among xylenols and ethylphenols. These results suggest that 2,4-xylenol, designated as a Class II chemical substance in the Pollutant Release and Transfer Register (PRTR), can be measured sensitively and selectively even when numerous isomers are present in the sample.