Biomaterial Database

Identification of pesticides by liquid chromatography--particle beam mass spectrometry using electron ionization and chemical ionization. 1998

C Aguilar, and F Borrull, and R M Marcé

Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira i Virgili, Tarragona, Spain.

Liquid chromatography-mass spectrometry (LC-MS) with a particle beam (PB) interface is used to separate and identify a group of pesticides. The mass spectra obtained under the different ionization modes, electron ionization (EI) and positive and negative chemical ionization (PCI and NCI) are compared. The operating conditions under each mode, determined by studying the influence on the ion abundance of the ion source temperature of the EI mode, and the gas pressure and ion source temperature in the methane CI were optimized. EI was more sensitive than PCI and NCI and of the latter two modes, NCI gave higher responses, especially for organophosphorus compounds. When on-line solid-phase extraction-LC-PB-MS was applied to real samples, limits of detection in full scan mode were in the range of 0.5 and 10 micrograms l-1 for EI. The analysis of real samples by on-line solid-phase extraction-LC-PB-MS enabled EI detection of one of the pesticides studied and confirmation by PCI and NCI. The combined EI/CI information also enabled the detection of some non-target compounds.

UI	MeSH Term	Description	Entries
D007477	Ions	An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
D010575	Pesticides	Chemicals used to destroy pests of any sort. The concept includes fungicides (FUNGICIDES, INDUSTRIAL); INSECTICIDES; RODENTICIDES; etc.	Pesticide
D002853	Chromatography, Liquid	Chromatographic techniques in which the mobile phase is a liquid.	Liquid Chromatography
D004583	Electrons	Stable elementary particles having the smallest known negative charge, present in all elements; also called negatrons. Positively charged electrons are called positrons. The numbers, energies and arrangement of electrons around atomic nuclei determine the chemical identities of elements. Beams of electrons are called CATHODE RAYS.	Fast Electrons,Negatrons,Positrons,Electron,Electron, Fast,Electrons, Fast,Fast Electron,Negatron,Positron
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D013058	Mass Spectrometry	An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.	Mass Spectroscopy,Spectrometry, Mass,Spectroscopy, Mass,Spectrum Analysis, Mass,Analysis, Mass Spectrum,Mass Spectrum Analysis,Analyses, Mass Spectrum,Mass Spectrum Analyses,Spectrum Analyses, Mass
D017022	Flow Injection Analysis	The analysis of a chemical substance by inserting a sample into a carrier stream of reagent using a sample injection valve that propels the sample downstream where mixing occurs in a coiled tube, then passes into a flow-through detector and a recorder or other data handling device.	Analysis, Flow Injection,Analyses, Flow Injection,Flow Injection Analyses,Injection Analyses, Flow,Injection Analysis, Flow