Analysis of forchlorfenuron in vegetables by LC/TOF-MS after extraction with the buffered QuEChERS method.
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.
Pesticide Residue Research Group, Faculty of Experimental Sciences, University of Almeria, 04071-Almera, Spain. avalverd@ual.es
Antonio
A
Valverde
Ana
A
Aguilera
Carmen
C
Ferrer
Francisco
F
Camacho
Anita
A
Cammarano
D002853:Chromatography, Liquid / Q000379:methods*; D013058:Mass Spectrometry / Q000379:methods*; D010671:Phenylurea Compounds / Q000032:analysis*; D010937:Plant Growth Regulators / Q000032:analysis*; D011725:Pyridines / Q000032:analysis*; D014675:Vegetables / Q000737:chemistry*
D010671:Phenylurea Compounds; D010937:Plant Growth Regulators; D011725:Pyridines; C116093:N-(2-chloro-4-pyridyl)-N'-phenylurea