Comparison of HPLC-DAD and LC-MS/MS for the determination and validation of pyriproxyfen in water solutions.

Pyriproxyfen is an insect growth regulator that affects the physiology of morphogenesis, reproduction and embryogenesis of insects. The molecule of pyriproxyfen bears little resemblance to endogenous insect juvenile hormone (JH), but it affects JH and ecdysteroid titers in a variety of arthropods. High-performance liquid chromatography with diode array (HPLC-DAD) method is a widely used method for the analyses of pyriproxyfen. Although the methods have been remarkably improved, tandem mass spectrometry (LC-MS/MS) systems with significant advantages have gradually replaced HPLC-DAD in many analyses. The aim of this study, was the evaluation of the two methods for linearity, limit of detection (LOD), limit of quantification (LOQ) selectivity and repeatability for the determination of pyriproxyfen in water solutions. Using HPLC-DAD the obtained LOD was 0.01 µg/ml with the LOQ of 0.03 µg/ml. The linearity was over 0.99 for the concentrations from 0.1 to 1.0 µg/ml with the repeatability RSD less than 11.7%. The LC-MS/MS method showed high reproducibility, as evident from the RSD values for intra-day and inter-day variability being 1.0-6.8% and 2.0-7.7%. The LC-MS/MS method exhibits linearity (R2>0.99) for the concentrations from 1.0 to 100.0 ng/ml with the repeatability RSD less than 12.7%. The obtained LOD and LOQ was 0.1 ng/ml and 1.0 ng/ml, respectively. The HPLC-DAD performed well in terms of various validation parameters, but showed a very high LOD and LOQ (considering low concentration level of pyriproxyfen used in mosquito treatment) compared to LC-MS/MS. [ABSTRACT FROM AUTHOR]