Determination of linuron in chamomile by LC-MS/MS using the QuEchERS extraction method

Abstract

Linuron is a selective herbicide used for the control of broadleaf weeds. Its mode of action is the inhibition of photosynthesis. The QuEChERS method for extraction of linuron residues from chamomile was used. The LC-MS/MS method was used for determination of linuron residues. Its linearity was studied in a range of 0.025-0.50 μg/ml using matrix-matched calibration, and the determination coefficient (R2) was higher than 0.99. Blank chamomile samples were spiked with linuron solution at three concentration levels yielding recoveries of over 90%. The internal standard added in all samples was isoproturon-d6. There were no linuron residues in chamomile flowers, while the residues ranged from 0.010 to 0.040 mg/kg in the flower stalk samples.

Linuron je selektivni herbicid, koji se koristi za suzbijanje širokolisnih korova. Njegov mehanizam delovanja je inhibicija fotosinteze (fotosistema II). Za ekstrakciju ostataka linurona iz uzoraka kamilice korišćena je QuEChERS metoda. Određivanje nivoa ostataka linurona vršeno je tečnom hromatografijom sa masenim spektroskopijom. Linearnost metode je ispitivana u opsegu koncentracija od 0.025 - 0.50 μg/ml, korišćenjem metode kalibracije u matriksu, pri čemu je koeficijent određivanja (R2) bio veći od 0.99. Tačnost metode je ispitivana obogaćivanjem kontrolnih uzoraka kamilice na tri koncentraciona nivoa. Prinos ekstrakcije je bio preko 90 %. Interni standard korišćen za analizu je bio izoproturon-D6. U cvetu kamilice nisu nađeni ostaci linurona, dok su u uzorcima drške bili u opsegu od 0.010-0.040 mg/kg.