Fragmentation of a non-ester pyrethroid insecticide by atmospheric pressure chemical ionization.
We elucidated the mechanism of fragmentation of ethophenprox (Mw = 376), a non-ester pyrethroid insecticide, in the presence of a proton, by using tandem mass spectrometry in combination with an atmospheric pressure chemical ionization technique in positive-ion mode. When methanol or acetonitrile was used as a solvent, no protonated ethophenprox ion was observed in the mass spectra even at low cone voltage (10 V), at which solvent cluster ions can exist. Instead of the protonated ion, an unexpected m/z 359 ion was strongly observed under all conditions examined. The product ion spectrum of the m/z 359 ion obtained under low collision energy (20 eV) showed that this ion can be formed through structural rearrangement involving water loss mainly via the six-centered pathway in this system, although two pathways (five-centered and six-centered) to form the m/z 359 ion are suggested in the literature.
Itoh
Nobuyasu
N
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1, Umezono, Tsukuba, Ibaraki 305-8563, Japan. nobuyasu-itoh@aist.go.jp
Kinumi
Tomoya
T
Inagaki
Shinsuke
S
Yarita
Takashi
T
D001274:Atmospheric Pressure; D007306:Insecticides / Q000737:chemistry*; D007477:Ions; D015394:Molecular Structure; D011722:Pyrethrins / Q000737:chemistry*; D012997:Solvents; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
D007306:Insecticides; D007477:Ions; D011722:Pyrethrins; D012997:Solvents