A sample introduction technique for obtaining a multiphoton ionization spectrum using picogram quantities of analyte...

A new sample introduction techniquefor ensuring the safety of a researcher during the measurement of hazardous compounds, such as dioxins, by supersonic jet spectrometry is described. The solution containing the analyte is introduced beneath the nozzle through a narrow capillary with a glass frit at the end, which is formed to vaporize only the solvent and to deposit the analyte. The first laser, that is, the second harmonic emission of a Nd: YAG laser, vaporizes the analyte and entrains it into a supersonic jet. The analyte molecule is ionized by the second laser, that is, an optical parametric oscillator. Ion measurement is achieved by a time-of-flight mass spectrometer. The analyte molecule is localized in the jet, thus permitting the amount of sample to be minimized. The minimum amount of phenol necessary for measurement of a multiphoton ionization spectrum by scanning the wavelength of the ionization laser in the 3-nm range was 180 pg, which is similar to or slightly less than the tolerable daily intake (TDI) of dioxin.