Determination of triazole fungicides in environmental water by magnetic solid-phase extraction coupled with UHPLC-MS/MS

Simultaneous determination of triazole fungicides in animal-origin food by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry

A method for the simultaneous determination of 21 triazole fungicides in animal-origin foods was established by using UPLC-MS/MS. The dilution solvent, extraction solvent, and QuEChERS purification adsorbent composition, were optimized. The response value of the target compound was the highest and the chromatographic peak shape was optimal under the following conditions: water-acetonitrile as the mobile phase, acetonitrile to extract the target compound, C18 (100 mg) as the adsorbent, and water-acetonitrile as the diluent. Our method was validated under electrospray ionization (ESI) + conditions with six animal-origin foods. The 21 triazole fungicides showed good linear relationships (0.1-20 μg∙L-1, R2 > 0.99). The limits of detection and quantitation ranged from 0.1 to 0.3 μg∙kg-1 and 0.3 to 0.9 μg∙kg-1, respectively. The average recoveries ranged from 72.0% to 114.8% with RSDs < 9.9%. Therefore, our method was suitable for the determination of pesticide residues in commercially available animal-origin samples.

Dispersive magnetic solid phase extraction of triazole fungicides based on polybenzidine/magnetic nanoparticles in environmental samples

A polybenzidine-modified Fe3O4@SiO2 nanocomposite was successfully synthesized through a chemical oxidation method and employed as a novel sorbent in dispersive magnetic solid phase extraction (DMSPE) for the preconcentration and determination of three triazole fungicides (TFs), namely diniconazole, tebuconazole, and triticonazole in river water, rice paddy soil, and grape samples. The synthesis method involved a polybenzidine self-assembly coating on Fe3O4@SiO2 magnetic composite. Characterization techniques such as FT-IR, XRD, FESEM, EDX, and VSM were used to confirm the correctness of the synthesized nano-sorbent. The target TFs were determined in actual samples using the synthesized nanocomposite sorbent in combination with gas chromatography-flame ionization detection (FID). Several variables were carefully optimized , including the sample pH, sorbent dosage, extraction time, ionic strength, and desorption condition (solvent type, volume, and time). Under the optimized experimental conditions, the method exhibited linearity in the concentration range 5-1000 ng mL-1 for triticonazole and 2-1000 ng mL-1 for diniconazole and tebuconazole. The limits of detection (LOD) for the three TFs were in the range 0.6-1.5 ng mL-1. The method demonstrated acceptable precision with intra-day and inter-day relative standard deviation (RSD) values of less than 6.5%. The enrichment factors ranged from 248 to 254. Finally, the method applicability was evaluated by determining TFs in river water, rice paddy soil, and grape samples with recoveries in the range 90.5-106, indicating that the matrix effect was negligible in the proposed DMSPE procedure.

Screening of new psychoactive substances in human plasma by magnetic solid phase extraction and LC-QTOF-MS

The emergence of new psychoactive substances (NPSs) is an increasing challenge in forensic toxicology. There are many extraction methods in use to isolate NPSs in biological fluids, including protein precipitation (PPT), liquid-liquid extraction (LLE), and solid phase extraction (SPE). However, there is a need to develop an effective extraction method with a short extraction time and low consumption of solvent. To meet these requirements, magnetic solid phase extraction (m-SPE) was attempted to isolate 40 NPSs in human plasma in this study. Forty NPSs (13 synthetic cannabinoids, 13 phenethylamines, 4 tryptamines, 4 other substances, 3 aminoindanes, 2 piperazines, 1 phencyclidine-type substance) were spiked in plasma and analyzed by m-SPE using COOH-functionalized multi-walled carbon nanotubes with magnetic nanoparticles (COOH-mMWCNTs). A liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) method was used for screening and identification of 40 target compounds. Method validation including limits of detection, recovery, matrix effect, and precision was performed for all 40 -target compounds. The limits of detection (LOD) of the 40 analytes were between 0.002 and 0.084 mg/L. Extraction recovery ranged from 36.9% to 110.6% (average 87%). Matrix effects ranged from -29.0% (ion suppression) to 9.8% (ion enhancement). Both intra- and inter-day precision values were less than 27.5% (RSD%). The accurate mass of QTOF-MS enabled the identification of analytes by exact monoisotopic mass and isotopic pattern. m-SPE was applied to extract 40 NPSs, and revealed less time-consuming and laborious than conventional SPE. This method proved to be an advantageous procedure to extract NPSs from biological fluids.

Hydroxyl-containing porous organic framework coated stir bar sorption extraction combined with high performance liquid chromatography-diode array detector for analysis of triazole fungicides in grape and cabbage samples

In this work, a hydroxyl-containing porous organic framework (HC-POF) was prepared by a simple solvothermal reaction with 1,4-phthalaldehyde and phloroglucinol as monomers. Sol-gel method was used to coat HC-POF on the glass stir bar. The prepared HC-POF coated stir bar shows better extraction performance for six triazole fungicides (TFs) compared to commercial polydimethylsiloxane and ethylene glycol-silicone coated stir bars. Fourier transform infrared Spectrometry and X-ray photoelectron Spectrometry were used to explore interactions between HC-POF coating and TFs. It is assumed that the coating mainly adsorbs TFs through π-π interactions, hydrogen bonding and hydrophobic interactions. Based on this fact, a new method of HC-POF coated stir bar sorptive extraction combined with high performance liquid chromatography-diode array detector was developed for the determination of six TFs in grape and cabbage samples. A series of extraction and desorption conditions were carefully optimized, including salt concentration, sample solution pH, stirring rate and desorption solvent. Under the optimized experimental conditions, the proposed method displayed limits of detection in the range of 0.022 -0.071 μg L^-1, which is the lowest among the reported SBSE methods for target TFs analysis. The linear range for six TFs was 0.1/0.2-500 μg L^-1 and the recoveries for the spiked grape and cabbage were 81.0-109% and 80.7-111%, respectively.