Analysis of forchlorfenuron in vegetables by LC/TOF-MS after extraction with the buffered QuEChERS method

J Agric Food Chem. 2010 Mar 10;58(5):2818-23. doi: 10.1021/jf904465s.

Abstract

This paper describes the application of liquid chromatography time-of-flight mass spectrometry (LC/TOF-MS), with electrospray ionization, for residue analysis of forchlorfenuron in tomato, zucchini and watermelon. The assessed method includes a sample preparation step based on the buffered QuEChERS approach. The TOF-MS fragmentation pattern of forchlorfenuron was studied at different fragmention voltages in the range of 120-270 V. Analyses were carried out under full-scan conditions by using the extracted ion chromatogram (XIC) of the m/z 248 ion with a 0.2 Da window. The linearity of the analytical response across the studied range of concentrations (10-500 microg/kg) was excellent, obtaining correlation coefficients higher than 0.999, and relative standard deviations of the response factors lower than 14%, for the 15 linear calibration curves of forchlorfenuron evaluated along the complete validation study. No significant matrix effects were observed. The signal-to-noise ratios obtained for the 10 microg/kg forchlorfenuron in matrix matched standards were >70 for all three matrices. Recovery studies were carried out on spiked tomato, zucchini and watermelon blank samples, at three concentration levels (10, 50, and 200 microg/kg) performing five replicates at each level. Forchlorfenuron mean recoveries ranged between 80% and 87% in watermelon and zucchini, and between 65% and 71% in tomato, obtaining in all cases relative standard deviation values lower than 10%. The method readily achieved a lowest validated level of 10 microg/kg, which was fit-for-purpose in residue monitoring applications.

Publication types

  • Validation Study

MeSH terms

  • Chromatography, Liquid / methods*
  • Mass Spectrometry / methods*
  • Phenylurea Compounds / analysis*
  • Plant Growth Regulators / analysis*
  • Pyridines / analysis*
  • Vegetables / chemistry*

Substances

  • Phenylurea Compounds
  • Plant Growth Regulators
  • Pyridines
  • N-(2-chloro-4-pyridyl)-N'-phenylurea