Determination of Atrazine, Acetochlor, Clomazone, Pendimethalin and Oxyfluorfen in Soil by a Solid Phase Microextraction Method
Određivanje atrazina, acetohlora, klomazona, pendimetalina i oksifluorfena u zemljištu metodom mikroekstrakcije u čvrstoj fazi
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Author
Djurovic, Rada
Gajic-Umiljendic, Jelena
Djordjevic, Tijana
Keywords
Solid phase microextractionPesticides
Soil
Mikroekstrakcija u čvrstoj fazi
pesticidi
zemljište
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Show full item recordAbstract
A solid phase microextraction (SPME) method for simultaneous determination of atrazine,
acetochlor, clomazone, pendimethalin and oxyfluorfen in soil samples was developed.
The method is based on a combination of conventional liquid-solid procedure and
a following SPME determination of the selected pesticides. Initially, various microextraction
conditions, such as the fibre type, desorption temperature and time, extraction time
and NaCl content, were investigated and optimized. Then, extraction efficiencies of several
solvents (water, hexane, acetonitrile, acetone and methanol) and the optimum number of
extraction steps within the sample preparation step were optimized.
According to the results obtained in these two sets of experiments, two successive
extractions with methanol as the extraction solvent were the optimal sample preparation
procedure, while the following conditions were found to be most efficient for SPME measurements:
100 μm PDMS fibre, desorption for 7 min at 2700C, 30 min extraction time and
5% NaCl content (w/v).
Detection and quantification were done by gas chromatography-mass spectrometry
(GC/MS). Relative standard deviation (RSD) values for multiple analysis of soil samples fortified
at 30 μg/kg of each pesticide were below 19%. Limits of detection (LOD) for all the
compounds studied were less than 2 μg/kg. Za istovremeno određivanje atrazina, acetohlora, klomazona, pendimetalina i oksifluorfena
u zemljištu ustanovljena je metoda mikroekstrakcije u čvrstoj fazi (SPME). Metoda
je zasnovana na kombinaciji klasične tečno-čvrste pripreme uzorka i SPME određivanja.
Izvršena je optimizacija najvažnijih mikroekstrakcionih parametara, kao što su izbor ekstrakcionog
vlakna, desorpciona temperatura i vreme, ekstrakciono vreme i sadržaj natrijumhlorida
(NaCl). Ispitivani su, takođe, ekstrakciona efikasnost različitih rastvarača (voda, heksan,
acetonitril, aceton i metanol), kao i optimalan broj ekstrakcionih koraka u toku pripreme
uzoraka zemljišta. Na osnovu rezultata dobijenih iz ova dva seta eksperimenata izabrani
su sledeći radni uslovi: dve sukcesivne ekstrakcije sa metanolom kao ekstrakcionim rastvaračem
u stupnju pripreme uzorka, dok su za mikroekstrakcione uslove uzeti: 100 μm PDMS
vlakno, desorpcija u trajanju od 7 min na 270ºC, ekstrakciono vreme – 30 min, uz dodatak
NaCl (5%, w/v).
Detekcija i kvantifikacija analita je vršena gasno-masenim spektrometrom (GC/MS).
Vrednosti relativnih standardnih devijacija (RSDs) višestruko ponovljenog merenja uzorka
obogaćenog do 30 μg/kg svakog pesticida su ispod 19%. Granice detekcije (LODs) za sve
pesticide uključene u ispitivanje su ispod 2 μg/kg.