Determination of dithiocarbamate fungicide residues by liquid chromatography/mass spectrometry and stable isotope dilution assay.
A rapid and very sensitive high-performance liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) method for the simultaneous determination of dithiocarbamate (DTC) fungicide residues in fruits and vegetables was developed. The surface extraction of samples used an alkaline buffer consisting of sodium hydrogen carbonate and DL-penicillamine. The three DTC subclasses, i.e. dimethyldithiocarbamates (DMDs), ethylenebis(dithiocarbamates) (EBDs), and propylenebis(dithiocarbamates) (PBDs), were separated on a Sequant ZIC-pHILIC column using an acetonitrile/10 mM ammonia gradient. Because of the instability of DTC residues extracted from plant samples, a stable isotope dilution assay was applied. For each DTC subclass, the limits of detection and quantification were approximately 0.03 mg kg(-1) and 0.05 mg kg(-1), respectively. Recoveries from grapes, cucumbers, tomatoes, and rucola, spiked in the range of 0.01-0.9 mg kg(-1), averaged between 90 and 100%.
Crnogorac
Goranka
G
Institute of Food Chemistry, University of Hohenheim, Garbenstrasse 28, Stuttgart, Germany.
Schwack
Wolfgang
W
D002851:Chromatography, High Pressure Liquid; D005506:Food Contamination / Q000032:analysis*; D005638:Fruit / Q000737:chemistry; D005659:Fungicides, Industrial / Q000032:analysis*; D007201:Indicator Dilution Techniques; D007554:Isotopes / Q000032:analysis; D010573:Pesticide Residues / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013859:Thiocarbamates / Q000032:analysis*; D014675:Vegetables / Q000737:chemistry; D015038:Zineb / Q000031:analogs & derivatives / Q000032:analysis; D015039:Ziram / Q000032:analysis
D005659:Fungicides, Industrial; D007554:Isotopes; D010573:Pesticide Residues; D013859:Thiocarbamates; C012509:propineb; D015039:Ziram; D015038:Zineb