Development of a dual LC-MS/MS platform for comprehensive monitoring of the photocatalytic transformation products of cyantraniliprole in wastewater effluents.

Abstract

Cyantraniliprole (CYA) is a second-generation anthranilic diamide insecticide whose increasing use in non-agricultural and urban settings poses a challenge for wastewater treatment plants (WWTPs). Given its low expected concentration and the potential formation of stable residues, the development of highly sensitive and selective analytical methods is essential. In this study, a comprehensive methodology was developed to monitor CYA and its transformation products (TPs) in wastewater effluents. The analytical strategy integrates dispersive liquid-liquid microextraction with a dual liquid chromatography with mass spectrometry (LC-MS/MS) platform, consisting of triple quadrupole (QqQ) and quadrupole time-of-flight (QTOF) analyzers. Using suspect and non-target screenings, eight TPs were tentatively identified based on high-resolution mass measurements and characteristic isotopic patterns. This structural elucidation allowed for the proposal of a detailed photocatalytic (TiO2) degradation pathway under ultraviolet A (UVA) provided by light emitting diode (LED) lamps, where an 86% degradation of the parent compound was achieved within 19 h. The methodology was subsequently validated and applied to real WWTP effluents previously fortified at 0.2 mg L-1 and subjected to solar photocatalysis (TiO2/Na2S2O8 tandem). In these complex matrices, CYA was quantified in the range of 0.07 to 0.14 mg L-1, and three principal TPs were consistently identified across all effluents. Specifically, IN-J9Z38, IN-HGW87, and IN-M2G98 emerged as the primary stable environmental markers, whereas two additional TPs (OH-CYA1 and CYA487) occurred only at trace levels with lower spectral information. Finally, an in silico environmental risk assessment characterized the insecticide and a selection of its main TPs as persistent and mobile species in the water column.