Determination of carbamate pesticide residues in vegetables and fruits by liquid chromatography-atmospheric pressure photoionization-mass spectrometry and atmospheric pressure chemical ionization-mass spectrometry
ABSTRACT A liquid chromatography-atmospheric pressure photoionization (APPI)-mass spectrometry method was developed for the determination of 22 carbamates including their metabolites in vegetables and fruits. For the optimization of APPI, several APPI ion source parameters were examined. As a result, many carbamates with APPI using the optimized parameter gave simple mass spectra, and a strong signal corresponding to [M + H](+) was observed except for aldicarb. However, some carbamate metabolites gave ammonium adduct ions [M + NH(4)](+) as base peak ions. The mean recovery of each carbamate from grape and onion samples spiked at 5 ng/g was 81.7-105.7%, with relative standard deviations of 3.3-5.9%. Furthermore, matrix constituents did not significantly influence the ionization efficiency. The limit of detection (S/N = 3) in grape and onion was in the range of 0.33-3.33 ng/g. For the robustness of this method, this system has been used to analyze 50 samples, and the intensities for all carbamates were found to be unaffected by the contamination of the APPI source by sample matrix constituents. This result indicates that the method is reliable.
- Journal of Pesticide Science 01/2012; 37(2):215-221. DOI:10.1584/jpestics.W12-05 · 0.51 Impact Factor
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ABSTRACT: A large number of toxic substances, such as pesticides, antibiotics and toxins, of varying origin and toxicity to human health are found in food. These compounds are frequently present at low concentration levels in very complex matrices, so sensitive, selective methodologies are needed for their analysis. Due to the chemical properties of these compounds, liquid chromatography (LC) is the separation technique of choice and the coupling to mass spectrometry (MS) provides the sensitivity and selectivity required. This article reviews the state of the art of LC–tandem MS (LC–MS/MS) for the analysis of organic toxics in food products. We also address instrumental aspects, such as ionization sources and analyzers, as well as confirmation and quantitation procedures. Moreover, we discuss the application of LC–MS/MS to compounds, such as pesticides, antibiotics, substances generated in cooking, and toxins in a range of food products.TrAC Trends in Analytical Chemistry 07/2005; 24(7-24):683-703. DOI:10.1016/j.trac.2005.04.012 · 6.61 Impact Factor