Razvoj i primena metode tečne hromatografije - tandem masene spektrometrije za određivanje pesticida u voću i voćnim sokovima

Abstract

Predmet ovog rada je razvoj i primena nove, brze i osetljive multirezidualne analitičke metode za određivanje tragova pesticida različitih hemijskih grupa u voćnim sokovima i voću. Za analizu su odabrani pesticidi koji spadaju u najčešće korišćene u našoj zemlji. Rad obuhvata razvoj metode disperzije matrice na čvrstoj fazi, za efikasnu ekstrakciju i predkoncentrisanje veoma različitih analita. Metoda obuhvata istovremeno razaranje, usitnjavanje i homogenizaciju čvstih i polučvstih uzoraka, kao i ekstrakciju i prečišćavanje analita. Kao sorbent korišćena je dijatomejska zemlja a dihlormetan je korišćen za eluiranje analita. Takođe, urađena je optimizacija hromatografskog razdvajanja i uspostavljen je protokol za potvrdu prisustva analita pomoću masenog detektora sa jonskim trapom. Kvantifikacija analita je urađena posmatranjem najintenzivnijeg fragmenta. Razvijena metoda za određivanje pesticida u voćnim sokovima obuhvata dvanaest pesticida i uspešno je validirana na uzorcima soka od jabuke, narandže, breskve i maline. Metoda je proširena sa još pet pesticida i uspešno validirana na uzorcima voća, jabuke, kajsije, narandže i jagode. Kao parametri validacije određivani su: prinos, linearnost, granica detekcija i granica kvantifikacije za sve ispitivane pesticide u svim ispitivanim matricama. Vrednosti dobijene za prinose u većini slučajeva su bile u opsegu od 70 do 120% uz relativnu standardnu devijaciju uglavnom ispod 20%. Dostignute su veoma niske granice detekcije i kvantifikacije. Razvijena metoda je primenjena na realne uzorke komercijalno dostupnih sokova i voća dostupnih na beogradskom tržištu

This study presents the development and application of a new, rapid and sensitive analytical method for determination of pesticide residues in fruit juices and fruits. Pesticides, chosen for the analysis, belong to different chemical classes and are among the most frequently used in our country. The study includes the development of the matrix solid-phase dispersion sample preparation method for extracting and preconcentrating different analytes. This sample preparation technique involves simultaneous disruption, fragmentation and homogenization of solid and semi-solid samples as well as extraction and clean-up of the analytes. Diathomeus earth was used as a dispersant, while dichloromethane was used as an eluting solvent. Also, optimization of the chromatographic separation was done and the protocol for reliable confirmation of pesticide residues with ion trap mass detector was established. The quantification of the analytes was carried out using the most sensitive transition. Developed method for pesticide analysis in fruit juices includes twelve pesticides and was successfully validated in apple, orange, peach and raspberry fruit juices. The method was expanded with five more pesticides and it was successfully validated for fruit samples, apple, apricot, orange and strawberry. The method was validated for accuracy, linearity, reproducibility, and sensitivity. Mean values for recoveries were in the range of 70–120 % for all tested matrices. Repeatability of the method, expressed as the relative standard deviation, was in general, lower than 20 %. Low limits of detection and quantification were readily achieved with this method for all tested pesticides. The applicability of the method to routine analysis was tested in real fruit and fruit juices samples with good performance.