Gas chromatographic determination of coumaphos and tau-fluvalinate residues in royal jelly produced under commercial conditions
Panos G Balayannis
A gas chromatographic analytical method was developed and used to determine coumaphos (Perizin) and tau-fluvalinate (Apistan) residues in royal jelly, The method involves sample dilution with a mixture of isopropyl alcohol/acetonitrile, centrifugation for phase separation, extraction with methylene chloride and analysis by gas chromatography-mass spectrometry. Recoveries ranged from 82-93% with coefficients of variation of 3-15% at the 95% confidence limit level. The quantification limit obtained was 5 ng/g for both coumaphos and tau-fluvalinate. The pesticides were applied inside the hives either as a spray (coumaphos) or as plywood inserts (tau-fluvalinate) to control varroa. It was found that when coumaphos was sprayed, the time interval between the last application and royal jelly collection (pre-harvest interval) should to be at least 42 days. No residues were detected when plywood inserts impregnated with tau-fluvalinate were used.
royal jelly production, coumaphos, tau-fluvalinate, pesticide residues, gas chromatography, mass spectrometry, varroosis, Greece