Analysis of pesticides by gas chromatography/multiphoton ionization/mass spectrometry using a femtosecond laser

Adan Li, Tomoko Imasaka, Tomohiro Uchimura, Totaro Imasaka

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOFMS) was utilized for analysis of a standard mixture sample containing 49 pesticides and 4 real samples using the third-harmonic emission (267. nm) of a femtosecond Ti:sapphire laser (100. fs) as the ionization source. A sample of a standard mixture of n-alkane was also measured for calibration of the retention time indices of the pesticides. Two photons are required for the excitation of n-alkane due to an absorption band located in the far ultraviolet region (140. nm). The n-alkane molecule in the excited state was subsequently ionized either directly or by absorbing another photon because of a high ionization potential. Due to a large excess of energy, the molecular ion was decomposed and formed many fragment ions. Compared to n-alkanes, most of the pesticides were softly ionized by the femtosecond laser; one photon was used for excitation and another was used for the subsequent ionization. The pesticides with no conjugated double bond had a lower ionization efficiency. The present analytical instrument was applied to several samples prepared from a variety of vegetables and a single fruit after pretreatment with solid-phase extraction. Three pesticides were found in these samples, although some of them were not detected by conventional GC/EI/MS-MS due to insufficient sensitivity and selectivity.

Original languageEnglish
Pages (from-to)52-59
Number of pages8
JournalAnalytica Chimica Acta
Volume701
Issue number1
DOIs
Publication statusPublished - Sep 2 2011

Fingerprint

Ultrashort pulses
Pesticides
Alkanes
Gas chromatography
Gas Chromatography
Ionization
Mass spectrometry
Mass Spectrometry
gas chromatography
Lasers
ionization
mass spectrometry
alkane
pesticide
laser
Photons
Ions
sapphire
ion
Ionization potential

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy

Cite this

Analysis of pesticides by gas chromatography/multiphoton ionization/mass spectrometry using a femtosecond laser. / Li, Adan; Imasaka, Tomoko; Uchimura, Tomohiro; Imasaka, Totaro.

In: Analytica Chimica Acta, Vol. 701, No. 1, 02.09.2011, p. 52-59.

Research output: Contribution to journalArticle

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