Extraction of pesticides from tea samples by tea solid-phase dispersion

Čajevi predstavljaju vrlo osjetljivu poljoprivrednu kulturu, zbog toga što su osjetljivi na velik broj štetočina, osobito grinje, kukce koji se hrane listovima i gusjenice te na razne trave i bolesti. Kako bi se minimizirali ovi problemi, najjednostavniji način je korištenje velikog broja pesticida, odnosno tvari ili smjesa sa svrhom kontroliranja, uništavanja, sprječavanja i odbijanja bioloških organizama. Međutim, opasni ostaci pesticida u čaju povezuju se s poremećajima i bolestima živčanog sustava te je zbog toga određivanje njihovih ostataka ključno za utvrđivanje preventivnih mjera u javnom zdravstvu. U ovom radu se za određivanje ostataka 13 različitih pesticida u čaju optimirala ekstrakcijska metoda raspršenja matice uzorka kroz čvrstu fazu. U svrhu određivanja optimalnih uvjeta spomenute ekstrakcije korišteni su različiti sorbensi (C18, osušene ljuskice jajeta, diatomejska zemlja i dr.) i različita otapala (čista otapala kao i različite kombinacije otapala) te čaj biljke trputac, organskog uzgoja, koji se sastoji od sluzi, iridoid glikozida i tanina. Iskoristivost ekstrakcije smjese 13 različitih pesticida određena je plinskom kromatografijom vezanom sa spektrometrijom masa. Utvrđeno je da je ekstrakcija najbolja pri sljedećim uvjetima: sorbens C18, otapalo za eluiranje heksan:aceton 8:2 te volumen otapala za eluiranje 5 mL. Nakon optimizacije te validiranja prethodno razvijene metode određivanja pesticida, ona je primjenjena na realnim uzorcima čajeva (čaj lista breze, lista maline, čaj biljke priljepače, maćuhice, maslačka, djeteline, crvene djeteline te preslice) čije se biljke mogu pronaći na većini livada i polja.Tea farming is vulnerable to a great multitude of pesticides, especially mites, leaf-eating beetles and caterpillars, and also to weeds and diseases. To minimise these problems, the most common practice in tea crop production is to use lots of pesticides, or substances and mixtures with the purpose of controlling, destroying, prevention and rejection of biological organisms. However, unsafe pesticide residues in tea have been associated with neurological dysfunction and disease. Consequently, determination of pesticide residues is at the forefront among preventive measures in public health safety. In this study, to determine residues of 13 different pesticides in tea, extraction method by matrix solid-phase dispersion was optimized. To determine the optimal conditions for mentioned extraction method, different sorbents (C18, dried egg flakes, diatomaceous earth, etc.), different solvents (pure solvent and various mixture of solvents) and plantain tea plants, which was organically farmed, consists mucus, iridoid glycosides and tannins, was used. Efficiency of extraction mixture of 13 different pesticides was determined by gas chromatography tandem mass spectrometry. The best extraction was achieved in following conditions: C18 sorbent, eluting solvent of hexane:acetone 8:2 and the volume of the eluting solvent 5 mL. After optimization and validation previously developed method for determination of pesticides, it was applied to real tea samples (tea birch leaf, raspberry leaf, tea plants catchweed, pansies, dandelions, clover, red clover and horsetails) which can be found on most grasslands and fields