Determination of thiacloprid, thiamethoxam and imidacloprid in tea samples by quenching terbium luminescence

Abstract

Consumption of herbal teas, infusions and other plant-related products has always been popular due to the related health benefits. However, the safety of these products needs to be assessed, for example monitoring the potential presence of contaminants such as pesticides. In this paper, we report an analytical method for determining three neonicotinoid insecticides − thiacloprid, thiamethoxam, and imidacloprid − that are widely used worldwide. This method is based on quenching by analytes of the luminescence signal of terbium ions. Terbium presents a timeresolved luminescence signal at 256/545 nm/nm, which is quenched by the presence of low concentrations of the selected analytes. Detection limits of 0.1, 0.2 or 0.75 μg ml −1 were obtained for thiamethoxam, thiacloprid and imidacloprid, respectively. Recovery experiments in different teas (green tea, black tea, chamomile, peppermint) were performed at concentrations lower than the maximum residue limits established by the European Union and the Codex Alimentarius for tea samples.In all cases, satisfactory recovery yields were observed, and the results were compared with a chromatographic reference method. The proposed method therefore proved suitable for quantifying these insecticides, fulfilling the current legislation.

Luminescent Probe Based on Terbium-Carbon Quantum Dots for the Quantification of Imidacloprid in Caneberries

“…IMID produced a decrease in the time-resolved luminescence of both Tb (III) and Eu (III). This effect was previously reported by our research group [ 35 , 36 ]. Therefore, we tested the effect produced in the system by the introduction of CQDs.…”

Luminescent Probe Based on Terbium-Carbon Quantum Dots for the Quantification of Imidacloprid in Caneberries

“…IMID produced a decrease in the time-resolved luminescence of both Tb (III) and Eu (III). Tis efect was previously reported by our research group [35,36]. Terefore, we tested the efect produced in the system by the introduction of CQDs.…”

Fluorescence Quenching Detection of Clothianidin in Fruit and Vegetable Samples Using MAPbBr3 Perovskite Quantum Dots

“…Current techniques for the detection of neonicotinoids include both chemical and optical detection methods: high-performance liquid chromatography (HPLC), liquid chromatography-tandem mass spectrometry (LC–MS/MS), − surface enhanced Raman spectroscopy (SERS), , enzyme-linked immunosorbent assay (ELISA), , and electrochemical, − electrochemiluminescence (ECL), and fluorescence (FL) spectrophotometry. − Thereinto, FL sensors based on quantum dots (QDs) are extensively utilized due to their simplicity, high sensitivity, high selectivity, stability, and applicability. QDs are semiconductor nanocrystals with size-tunable optical and electronic properties and have found applications in light-emitting diodes, biotechnology, catalysis, sensors, and solar cells .…”