ABSTRACT
A method for simultaneous determination of 25 kinds of fungicides in cereals, vegetables and fruits using SPE-LC-Q-TOF/MS technique was developed.The samples were extracted with acetonitrile containing 1% (V/V) acetic acid, purified by solid phase extraction (SPE) with a Crabon/NH2 cartridge, eluted with acetonitrile-toluene(3∶1, V/V), separated by a reversed phase C18 column, gradiently eluted with acetonitrile and 0.1% formic acid solution (Containing 5 mmol/L ammonium acetate), determined by LC-Q-TOF/MS, and quantified by external standard method.A data base of the accurate mass numbers and a library which contains 25 kinds of fungicides were established.The automatic retrieval of detection results was carried on according to the characteristics of the compound, such as accurate mass, retention time, isotope peak distribution, isotopic ratios, and so on.Based on the above results, the qualitative identifications of the 25 new fungicides were accomplished without the contrast of standard substances.The results indicated that 25 fungicides showed good linearity in the range of 0.02-200 μg/L, and the limits of detection (LOD) and the limits of quantification (LOQ) were 0.01-5.00 μg/kg and 0.02-20.00 μg/kg, respectively.The linear relative coefficients were greater than 0.995.The recoveries were in the range 71.8%-114.0% and the relative standard deviations (RSD) were ranged from 0.1% to 21.3% (n=3).The method has some advantages such as simplicity, rapidity and high sensitivity, and is suitable for the rapid determination of the common fungicides in cereals, vegetables and fruits.