Determination of Pesticides by Gas Chromatography Combined with Mass Spectrometry Using Femtosecond Lasers Emitting at 267, 400, and 800 nm as the Ionization Source

Abstract

A standard sample mixture containing 51 pesticides was separated by gas chromatography (GC), and the constituents were identified by mass spectrometry (MS) using femtosecond lasers emitting at 267, 400, and 800 nm as the ionization source. A two-dimensional display of the GC/MS was successfully used for the determination of these compounds. A molecular ion was observed for 38 of the compounds at 267 nm and for 30 of the compounds at 800 nm, in contrast to 27 among 50 compounds when electron ionization was used. These results suggest that the ultraviolet laser is superior to the near-infrared laser for molecular weight determinations and for a more reliable analysis of these compounds. In order to study the conditions for optimal ionization, the experimental data were examined using the spectral properties (i.e., the excitation and ionization energies and absorption spectra for the neutral and ionized species) obtained by quantum chemical calculations. A few molecules remained unexplained by the currently reported rules, requiring additional rules for developing a full understanding of the femtosecond ionization process. The pesticides in the homogenized matrix obtained from kabosu ( citrus sphaerocarpa) were measured using lasers emitting at 267 and 800 nm. The pesticides were clearly separated and measured on the two-dimensional display, especially for the data measured at 267 nm, suggesting that this technique would have potential for use in the practical trace analysis of the pesticides in the environment.

Resonant and non-resonant femtosecond ionization mass spectrometry of organochlorine pesticides

“…It has been reported that a bulky side chain, i.e., a low frequency mode in a molecule accelerate fragmentation. 24 As can be seen from the chemical formula of DDT (Fig. S-1), it contains two bulky groups and HCB has a rigid Please do not adjust margins Please do not adjust margins structure, which explains the more dissociative nature of DDT compared to HCB.…”

“…23 This technique has been applied for the measurement of analytically important compounds, e.g., chlorinated aliphatic/aromatic hydrocarbons such as OCPs. 24 However, the mechanism responsible for this ionization has not yet been investigated to date.…”

Evaluating the Creaming of an Emulsion via Mass Spectrometry and UV–Vis Spectrophotometry

“…15−18 MPI-TOFMS is normally applied to atomic/molecular spectroscopy 19−21 and to the trace analysis of compounds in real samples such as in an environmental setting. 22−27 Although MPI is generally an ionization method for analytes in a gas phase, several vaporization methods for liquid samples have also been studied. 28−30…”

Nanostructured Fe2O3-ZnO modified GCE nanosensor for dinobuton pesticide determination in environmental samples

“…If the pesticides applied on soils, it persists for a long time, because its degradation is slow and it is harmful to the human being [2][3][4][5], therefore, there is necessary to monitoring of pesticides. Many monitoring techniques have been reported for the quantitative determination of pesticides such as spectrophotometry, capillary electrophoresis, highperformance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), and ultraperformance liquid chromatography coupled to tandem mass spectrometry [6][7][8][9][10][11][12][13][14][15]. Thus, electrochemical methods offer a versatile stand for sensitive, selective and reproducible evaluating of pesticides.…”