Detection And Identification Of Organophosphorus Pesticides Using Ion Mobility Spectrometry
2004
Haj Aqa Me`mar, Ahmad | Ja`fari, Mohammad Taqi | A`zimi, Mehdi | Borhani, Kurosh | Doktor Zadeh, Hoseyn | Taj Bakhsh, | Narimani, A`bbas
Pesticide intoxications are widely occurred in agriculture, especially in the developing countries. Pesticide poisonings are known to be a major public health problem. For this reason, there are approximately 220,000 deaths per year on a word-wide scale [1]. Therefore rapid, simple and sensitive field methods are required to check the presence of these compounds. Organophosphorus compounds (OPCs), are the major group of the pesticides. So far, traditional methods such asgas chromatography (GC), high performance liquid chromatography (HPLC) and GC coupled with mass spectrometry (GC-MS) have been used for analysis of these compounds [1]. However these methods are known to be expensive and quite laborious. Ion mobility spectrometry (IMS) has been proven to be one of the best methods for the detection of trace level of OPCs. This method can be used for analyzing volatile or semi-volatile organic compounds that have a high proton affinity or electron affinity in the gas phase]. Organophosphorus compounds, have high proton affinities and therefore readily protonate in the reaction region of the ion mobility spectrometer, even in the presence of several other constituents present in ambient air. In this work, detection and identification of several organophosphorus pesticides such as malathion, ethion, phosalon, fenitrothion and dichlorovos were conducted by using ion mobility spectrometer with 63Ni as an ionization source. Stock standard solutions(50 ppm) of these compounds were prepared in acetone, then working solutions were made by successive dilution of the stock solution. The minimum detection limits that were obtained for these compounds are 1, 1, 2, 5 and 10 ng, respectively. Furthermore, in this study, the influence of cell temperature on the ion mobility spectra of these compounds was investigated. Comparison of the detection limits obtained by IMS with that of other methods shows that IMS is more sensitive than other methods. Furthermore IMS has the capability of being made as portable instrument for detection of these compounds in environment.
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