Development of Heat-Induced Homogeneous Liquid–Liquid Microextraction for Extraction and Preconcentration of Neonicotinoid Insecticides from Fruit Juice and Vegetable Samples

Rhodamine and related substances in food: Recent updates on pretreatment and analysis methods

Rhodamine, a colorant prohibited in various consumer products due to its demonstrated carcinogenic, mutagenic, and toxic properties, necessitates the development of a straightforward, efficient, sensitive, environmentally friendly, and cost-effective analytical method. This review provides an overview of recent advancements in the pretreatment and determination techniques for rhodamine across diverse sample matrices since 2017. Sample preparation methods encompass both commonly used pretreatment techniques such as filtration, centrifugation, solvent extraction, and cloud point extraction, as well as innovative approaches including solid phase extraction, dispersive liquid-liquid microextraction, hollow fiber liquid phase microextraction, magnetic solid phase extraction, and matrix solid phase dispersion. The analytical techniques encompass high performance liquid chromatography, surface-enhanced Raman scattering, and sensor-based methods. Furthermore, a comprehensive examination is conducted to offer insights for future research on rhodamine regarding the advantages, disadvantages, and advancements in various pretreatment and determination methodologies.

Identification of key factors affecting neonicotinoid residues in crops and risk of dietary exposure

Neonicotinoids, widely used on farmland, are ubiquitous in food; however, their distribution among various crops and associated exposure risks at the provincial level in China remain unclear. We collected 19 types of crop samples (fruits, vegetables, and tea) from farmland in nine prefectural cities in Zhejiang Province, China. We analyzed nine commonly used neonicotinoids in the edible portions of these crops. A notable detection rate (42.1 %-82.9 %) and high residual neonicotinoid concentrations (278 ± 357 ng/g) were observed. Tea exhibited the highest residue, followed by fruits, and vegetables showed the lowest (P < 0.05). Neonicotinoid ratios in crops to soil (R_C/S) and soil to water (R_S/W) were defined to discern insecticide distribution across different environments. Increased water solubility leads to increased migration of neonicotinoids (R_S/W) from agricultural soils to water through runoff, thereby increasing the relative contribution of nitenpyram and dinotefuran in water. In comparison with other studied compounds, all crops demonstrated the strongest soil uptake of thiamethoxam, denoted by the highest R_C/S value. Elevated R_C/S values in tea, pickled cabbage, and celery suggest increased susceptibility of these crops to neonicotinoid absorption from the soil (P < 0.05). Estimated dietary intake for teenagers, adults and elders was 8.9 ± 0.5, 8.9 ± 0.6, and 8.8 ± 0.3 μg/kg/d, respectively, below the reference dose (57 μg/kg/d). Teenagers, compared to adults and elders, exhibited significantly higher neonicotinoid exposure through fruit consumption, emphasizing the need for increased attention to neonicotinoid exposure among vulnerable populations.

Synthesis of phosphate-functionalized magnetic porous organic polymer: A sorbent for sensitive determination of neonicotinoid insecticides in water and lemon juice

There is an urgent need to prepare advanced functional materials for extraction and enrichment of trace organic pollutants from different samples. In this work, two novel phosphate-functionalized porous organic polymers (DBP-POP and DPP-POP) were synthesized for the first time. Compared with phosphate-free counterpart, both phosphate-functionalized POPs showed excellent adsorption performance for the neonicotinoids due to the hydrogen bonding, π-π interaction and hydrophobic interaction. For ease of separating the sorbent from solution, magnetic DBP-POP (M-DBP-POP) was further prepared as sorbent to extract neonicotinoids from environmental water and lemon juice samples prior to their determination by high performance liquid chromatography-ultraviolet detection. Under optimal conditions, the detection limits (S/N = 3) of the method were 0.01-0.08 ng mL-1 for water and 0.03-0.10 ng mL-1 for lemon juice. The recoveries were in the range of 80.0% to 113.0% with relative standard deviation less than 10.6%. This work demonstrated the feasibility of phosphate-functionalized POPs for adsorption applications.

Zeolite H-Beta as a Dispersive Solid-Phase Extraction Sorbent for the Determination of Eight Neonicotinoid Insecticides Using Ultra-High-Performance Liquid Chromatography—Tandem Mass Spectrometry

In this study, a dispersive solid-phase extraction (DSPE) pretreatment procedure using zeolite H-Beta as a sorbent was exploited for the determination of eight neonicotinoids in bottled water and honey products based on ultra-high-performance liquid chromatography–tandem mass spectrometry analysis. The zeolite H-Beta was demonstrated to be a suitable sorbent for neonicotinoid insecticides, even after 10 recycles of reuse. The method performance was evaluated by the linearity (R2 ≥ 0.998), recovery (71–108%), precision (0.1–7.8%), limit of detection (0.05–0.1 ng/mL) and limit of quantification (0.1–0.2 ng/mL), which suggested excellent stability and high sensitivity with the use of the DSPE procedure. The method was further successfully applied in the test of neonicotinoid insecticides in 34 samples. Zeolite H-Beta shows promise as an efficient and practical material for monitoring neonicotinoid insecticides in bottled water and multiplex honey matrices.

An environmentally friendly and novel amine-based liquid phase microextraction of quercetin in food samples prior to its determination by UV-vis spectrophotometry

A novel and environmentally-friendly method, which includes determination of trace amounts of quercetin in samples by using UV-vis spectrophotometry after enrichment with amine-based liquid phase microextraction (LPME), has been developed. As extraction solvent, N,N-dimethyl-n-octylamine has been used and the quercetin concentration in extraction phase was determined by UV-vis spectrophotometry at 382.5 nm. Important analytical parameters such as pH, extraction solvent type and volume, sample volume, extraction time were optimized by the method. Quercetin in the sample solution was extracted to 200 μL of N,N-dimethyl-n-octylamine phase at pH 4.0. The detection limit (LOD) and the quantitation limit (LOQ) values for quercetin were calculated as 0.07 μg·mL^-1 and 0.24 μg·mL^-1, respectively. Accuracy studies for the food samples was carried out by addition and recovery experiments. The developed method has been successfully applied to different food samples including spinach, green pepper, red onion and dill weed.