Epsilon Archive for Student Projects

Abstract

Honey is a product that may contain pesticide residues due to contamination from bees pollinating various plants as well as elimination of vermin inside the hive. Different methods are needed for analysis of pesticides, since the term includes a wide range of different substances. National Food Administration lacks a validated method for determination and quantification of pesticides in honey using liquid chromatography tandem mass spectrometry, LC-MS/MS. The technique is especially important in analysis of polar and non-volatile pesticides, where gas chromatography is not functioning optimally. After investigating what pesticides could be found in honey produced in Sweden, a number of four pesticides suitable for analysis with LC-MS/MS was compiled; boscalid, impidacloprid, tau-fluvalinate and thiacloprid. A validated multi method for pesticide analysis in fruit and vegetables using LC-MS/MS was utilized as reference method, as a new method was developed. Some of the alterations in the new method included addition of water, changed order of addition of salts, centrifuge settings and shakings of samples. Performing validation experiments at three levels; 0.01 μg/g, 0.02 μg/g and 0.1 μg/g, yielded recovery in the range from 69.4% to 91.8% with relative standard deviation <19%. These figures met, with one exception, the requirements for validation of new methods at National Food Administration and also held linear correlation coefficients higher than 0.97. Three labels of honey, with different origins, were used in the experiments. One of the honey labels formed emulsion during extraction. Absence of a separate ethyl acetate phase caused difficulties when creating a suitable extract for determination and quantification by LC-MS/MS. A special extraction procedure was developed for that specific honey label enabling extraction. As successful extraction procedures were developed and recovery tests yielded satisfying results, the aim to develop an analysis method for determination of pesticide residues in honey using liquid chromatography tandem mass spectrometry was fulfilled.

Honung är en produkt som kan innehålla pesticidrester på grund av kontamination av bin när de
pollinerar olika växter och även från skadedjursbekämpning inne i bikupan. Olika tekniker behövs
för analys av pesticidrester eftersom begreppet inkluderar en bred grupp av olika substanser.
Livsmedelsverket saknar en validerad metod för bestämning och kvantifiering av pesticider i
honung med hjälp av LC-MS/MS. Tekniken är speciellt viktig för analys av polära och icke-volatila
pesticider, då analys med gaskromatografi inte är optimalt för dessa pesticider. Efter undersökning
av vilka pesticider som kan påträffas i honung producerad i Sverige, sammanställdes en lista med
fyra pesticider som kan analyseras av LC-MS/MS; boskalid, imidakloprid, tau-fluvalinat och
tiakloprid. En validerad multimetod för pesticidanalys i frukt och grönsaker med användning med
LC-MS/MS användes som referensmetod när en ny metod utvecklades. Några av ändringarna i den
nya metoden inkluderade tillsats av vatten, ny ordningsföljd vid tillsats av salter,
centrifuginställningar och skakningar av prover. Valideringsexperimenten genomfördes på tre
nivåer; 0,01μg/g, 0,02