Automated Photochemically Induced Method for the Quantitation of the Neonicotinoid Thiacloprid in Lettuce

Abstract

In this work, we present an automated luminescence sensor for the quantitation of the insecticide thiacloprid, one of the main neonicotinoids, in lettuce samples. A simple and automated manifold was constructed, using multicommutated solenoid valves to handle all solutions. The analyte was online irradiated with UV light to produce a highly fluorescent photoproduct (λexc/λem = 305/370 nm/nm) that was then retained on a solid support placed in the flow cell. In this way, the pre-concentration of the photoproduct was achieved in the detection area, increasing the sensitivity of the analytical method. A method-detection limit of 0.24 mg kg−1 was achieved in real samples, fulfilling the Maximum Residue Limit (MRL) of The European Union for thiacloprid in lettuce (1 mg kg−1). A sample throughput of eight samples per hour was obtained. Recovery experiments were carried out at values close to the MRL, obtaining recovery yields close to 100% and relative standard deviations lower than 5%. Hence, this method would be suitable for routine analyses in quality control, as an alternative to other existing methods.

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

“…Approximately 50 g of each sample was thoroughly ground and homogenized. A QuEChERS extraction adapted from [ 34 ] was used. Specifically, a QuEChERS extraction kit (ISOLUTE QuEChERS) with GCB was used for all the samples.…”

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

“…Approximately 50 g of each sample was thoroughly ground and homogenized. A QuEChERS extraction adapted from [34] was used. Specifcally, a QuEChERS extraction kit (ISOLUTE QuEChERS) with GCB was used for all the samples.…”

Simultaneous determination of acetamiprid and 6‐chloronicotinic acid in environmental samples by using ion chromatography hyphenated to online photoinduced fluorescence detector

“…But, this multiadvantageous technique can be reinstated by adding a simple and cost-effective postcolumn photochemical reactor in a pre-existing LC-FLD system for the online photoconversion of both nonfluorescent analytes into their respective fluorescent form. This online photo derivatization offers multifold advantages over chemical derivatization, such as online operation, no need of extra solvents and reagents, time-saving, avoiding derivatization labor, minimum generation of waste effluents, highly reproducible, and most importantly entail high intensity of photochemically induced fluorescence (PIF) signals [6,12,[22][23][24][25][26][27][28]. This postcolumn addition of the photochemical reactor has overcome the problem of the nonfluorescent behavior of neonicotinoids.…”