Validation of QuEChERS-based UPLC-MS/MS method for determination of quinoid niclosamide (LDS) residue in water, soil and rice samples.

A sensitive, rapid and easy analytical method was validated for the determination of quinoid niclosamide (LDS) molluscicide in water, rice and soil using a QuEChERS extraction procedure and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection. The LDS was extracted by using acetonitrile and then cleaned up by using dispersive solid-phase extraction with florisil and C18 sorbents. The determination of the target compound was achieved in less than 3 min using an electrospray ionisation source in negative mode. The overall average recoveries for this method in water, rice and soil matrix at three fortified levels ranged from 82.54 to 99.9%, with relative standard deviations in the range of 1.51 to 4.86% (n = 5). The calculated limits of detection were lower than 0.1 µg kg−1 and quantification was 5 µg kg−1; these values were much lower than the maximum residue levels established by the Australian standard (0.01 mg kg−1). The results of the method validation confirmed that this proposed method is convenient and reliable for the determination of LDS molluscicide in water, rice and soil samples. [ABSTRACT FROM AUTHOR]