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This study employed QuEChERS as an efficient sample clean-up and extraction method for the determination of pyridaphenthion in aqueous, fruit and vegetable samples by high performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection. All of the instrumental parameters were carefully optimized to obtain a sharp analyte signal eluted at an short retention time. The analyte was eluted on a C18 column using an isocratic mobile phase system that was composed of 40:60 (v/v) water:acetonitrile. The linear working range of pyridaphenthion was from 10 μg/L to 50 mg/L, and the respective limits of detection and quantification were determined to be 2.4 and 8.1 μg/L. The instrumental precision was very good with a relative standard deviation value of 1.8%. Spike recovery studies were used to validate the accuracy and applicability of the method for food and aqueous samples. Degradation studies for pyridaphenthion under UV radiation were also performed with a liquid chromatography quadrupole time of flight mass spectrometer. [ABSTRACT FROM AUTHOR]

• A metal sieve-linked double syringe (MSLDS) system was developed for the determination of pyridaphenthion pesticide. • The developed method is fast, cheap and easy to operate. • The LOD and LOQ values were found to be 0.8 and 2.7 µg/L, respectively. • The method was applied to soybean sprouts with satisfactory percent recoveries. A novel analytical strategy for the trace determination of pyridaphenthion pesticide was developed in this study. Gas chromatography-mass spectrometry (GC–MS) was used for the accurate, feasible and precise determination of this analyte. Liquid phase microextraction (LPME) was performed with a metal sieve linked double syringe (MSLDS) system, which eliminated the need for a disperser solvent. In order to increase extraction efficiency for the analyte, all variable parameters were optimized and the system analytical performance of the proposed method was determined. Limit of detection and quantification (LOD and LOQ) values of pyridaphenthion were found to be 0.8 and 2.7 µg L−1, respectively. Compared to GC–MS system's analytical performance, the developed method provided approximately 273-folds improvement in the detection limit of the analyte. Applicability/accuracy of the developed analytical strategy was checked by recovery experiments carried out with soybean sprouts, and the results obtained were satisfactory. [ABSTRACT FROM AUTHOR]

• Nostoc muscorum can bio-accumulate large amount of pyridaphenthion (PY). • N. muscorum induced PY detoxification & degradation to less toxic compound. • PY induced photosynthesis inhibition & oxidative stress, particularly in Anabaena laxa. • Improved antioxidative capacity of N. muscorum explains its high stress tolerance. • N. muscorum is a promising candidate for PY remediation. Excessive use of organophosphorus pesticides such as pyridaphenthion (PY) to constrain insects induced crop loss, results in soil and water sources contamination. Cyanobacteria are sensitive biological indicators and promising tools for bioremediation of soil and water pollutants. To understand PY toxicity, detoxification and degradation in cyanobacteria, we performed a comparative study in the two diazotrophic cyanobacteria; Anabaena laxa and Nostoc muscorum. They were exposed to mild (5 mg/L) and high (10 mg/L) concentrations of PY for 7 days. Compared to A. laxa, N. muscorum efficiently showed high PY accumulation and degradation to a safe environmentally product; 6-hydroxy-2-phenylpyridazin-3(2 H)-one. PY inhibited cell growth and reduced Chl a content and photosynthesis related enzymes (PEPC and RuBisCo) activities in both species, but to less extend in N. muscorum. It also induced oxidative damage, particularly in A. laxa , as indicated by high H 2 O 2 , lipid peroxidation and protein oxidation levels and increased NADPH oxidase enzyme activity. N. muscorum invested more in antioxidants induction, i.e., induced ascorbate and glutathione cycle, however, these antioxidants increments in A. laxa were less pronounced. Overall, this study provides more in-deep insights into the PY toxicity and the role of N. muscorum as a promising PY remediator. [ABSTRACT FROM AUTHOR]