Headspace Solid Phase Microextraction in Pesticide Residues Analysis: 1. Optimisation of Extraction Conditions
Mikroekstrakcija u čvrstoj fazi - uzorkovanje iz gasovite faze u određivanju ostataka pesticida: 1. Optimizacija uslova ekstrakcije
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Author
Djurovic, Rada
Milinovic, Jelena
Markovic, Mirjana
Markovic, Dragan
Keywords
HS/SPMEOptimisation
Pesticide residues
optimizacija
ostaci pesticida
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Show full item recordAbstract
The method of headspace solid phase microextraction (HS/SPME) was successfully
used in a simultaneous multicomponent analysis of hexachlorobenzene (HCB), tefluthrin,
heptachlor, aldrin, chlorpyrifos, fenthion and bifenthrin in aqueous medium. Measurements
were performed using a nonpolar polydimethyl siloxane (PDMS) fiber. Detection and quantification were done by gas chromatography/mass spectrometry (GC/MS).
Optimal conditions for HS/SPME were determined both by performing extraction at
different temperatures and examining extraction time profiles at constant temperature.
Optimal extraction temperature for each pesticide studied was determined as follows: 60°C
for HCB and for heptachlor, 80°C for aldrin and for chlorpyrifos, fenthion and tefluthrin, and
temperature exceeding 80°C for bifenthrin. For the pesticide mixture studied, 60°C was
identified as the optimum extraction temperature.
Based on the time profiles obtained, it was confirmed that satisfactory extraction sensitivity
can be obtained even for extraction times shorter than the time required to reach
a sorption equilibrium. This conclusion was confirmed by linear concentration profiles
obtained for the following ranges: 0.05-10 ng/ml (HCB), 0.05-25 ng/ml (tefluthrin), 0.05-40
ng/ml (heptachlor), 0.05-40 ng/ml (aldrin), 0.05-25 ng/ml (chlorpyrifos), 0.05-25 ng/ml (fenthion)
and 0.05-25 ng/ml (bifenthrin).
Relative standard deviation (RSD) values for triplicate measurements did not exceed
15%. Metoda mikroekstrakcije u čvrstoj fazi – uzorkovanje iz gasovite faze (HS/SPME) je uspešno primenjena za istovremenu višekomponentnu analizu heksahlorobenzena (HCB), teflutrina, heptahlora, aldrina, hlorpirifosa, fentiona i bifentrina u vodenoj sredini. U radu je korišćeno nepolarno polidimetilsiloksansko vlakno (PDMS). Detekcija i kvantifikacija analita je
vršena metodom gasno-masene spektrometrije (GC/MS). Optimalni uslovi HS/SPME metode su odreðeni praæenjem efikasnosti ekstrakcije na različitim temperaturama, odnosno u funkciji vremena na konstantnoj temperaturi. Za svaki
ispitivani pesticid, određena je optimalna temperatura ekstrakcije: 60°C za HCB i heptahlor,
70-80°C za aldrin, hlorpirifos, fention i teflutrin, temperatura veæa od 80°C za bifentrin. Za ispitivanu smešu, temperatura od 60°C je izabrana za praktičan rad. Na osnovu dobijenih vremenskih profila, utvrđeno je da se dobra osetljivost metode postiže i kada se radi sa vremenom ekstrakcije kraæim od ravnotežnog. Ovaj zaključak je potvrđen i eksperimentalno
dobijenim koncentracionim profilima, pri čemu su dobijeni sledeći opsezi linearnosti: 0.05-
10 ng/ml (HCB), 0.05-25 ng/ml (teflutrin), 0.05-40 ng/ml (heptahlor), 0.05-40 ng/ml (aldrin),
0.05-25 ng/ml (hlorpirifos), 0.05-25 ng/ml (fention) i 0.05-25 ng/ml (bifentrin).
Relativne standardne devijacije (RSD) računate na osnovu tri ponovljena merenja su uvek bile manje od 15%.