A modified QuEChERS method for simultaneous determination of 73 pesticides, 23 PCBs and 16 PAHs in wheat by GC-MS/MS.

In this study, a modified QuEChERS method for the simultaneous determination of 73 pesticides, 23 PCBs and 16 PAHs in wheat was developed by gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). The sample was first hydrated with 4 mL of ultrapure water, extracted with 10 mL of acetone-hexane (1 : 1, V:V), and then cleaned up with a mixture of 50 mg of PSA, 150 mg of C18, and 400 mg of anhydrous MgSO. Under the optimized conditions, the samples were analyzed by GC-MS/MS for quantitative analysis using the matrix-matched external standard method.

Revisiting Cyanobacteria-Temperature Dynamics: Intraspecific Competition and Trait Diversity as Keys to Predicting Harmful Algal Blooms under Climate Change.

Cyanobacterial harmful algal blooms are expanding spatiotemporally, with an increasing occurrence of cold-water cyanobacterial blooms (CWCBs), intensifying ecological and water quality challenges. While abiotic drivers have been identified as contributors to CWCBs, the role of biotic factors─particularly the adaptation induced by the shifts in intraspecific trait distributions─in this process remains largely unexplored. Here, we tested the hypothesis that the thermal history of cyanobacteria affects their thermal adaptations by reshaping the distribution of optimum growth temperature ().

Rapid determination of volatile benzene derivatives and chlorobenzenes in goat's milk by HS-SPME-GC-MS/MS.

A method for the determination of eight benzenes (BTEXs) and twelve chlorobenzenes (CBs) in goat's milk by headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS/MS) was developed. The study investigated the impact of various factors such as extraction fiber type, salt amount, equilibrium conditions, and desorption conditions on the outcomes. Target analytes were separated on a DB-HeavyWAX column and quantified using the external standard method.

Simultaneous determination of 78 pesticide residues and 16 mycotoxins in tsampa by an improved QuEChERS method coupled with ultra performance liquid chromatography-tandem mass spectrometry.

Tsampa may contain pesticide residues and mycotoxins, which may pose a risk to human health. Currently, pesticide detection and mycotoxin detection are two independent experiments. To improve the efficiency of the analysis, a method based on QuEChERS combined with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of 78 pesticides and 16 mycotoxins in tsampa was developed.

[Rapid determination of 15 -nitrosamines in air-dried yak meat using one-step QuEChERS-gas chromatography-triple quadrupole mass spectrometry].

A method based on gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) coupled with one-step QuEChERS technique was developed for the simultaneous determination of 15 -nitrosamines in air-dried yak meat. The hydration volume, extraction solvent, extracting salt, and cleaning material were optimized according to the characteristics of the -nitrosamines and sample matrix. The optimized conditions were as follows: 10 mL of purified water for sample hydration, acetonitrile as the extraction solvent for the sample after hydration, 4.

Assessment of in-situ monitoring and tracking the vertical migration of cyanobacterial blooms using LISST-HAB.

Cyanobacterial harmful algal blooms (cyanoHABs) are becoming increasingly common in aquatic ecosystems worldwide. However, their heterogeneous distributions make it difficult to accurately estimate the total algae biomass and forecast the occurrence of surface cyanoHABs by using traditional monitoring methods. Although various optical instruments and remote sensing methods have been employed to monitor the dynamics of cyanoHABs at the water surface (i.

Combined effect of freshwater salinization and harmful algae on the benthic invertebrate Chironomus pallidivittatus.

Global climate change as well as human activities have been reported to increase the frequency and severity of both salinization and harmful algal blooms (HABs) in many freshwater systems, but their co-effect on benthic invertebrates has rarely been studied. This study simultaneously examined the joint toxicity of salinity and different cyanobacterial diets on the behavior, development, select biomarkers, and partial life cycle of Chironomus pallidivittatus (Diptera). High concentrations of salts (e.

Rapid flotation of mediated by high light exposure: implications for surface scum formation and cyanobacterial species succession.

Increasing occurrences of surface scum have been observed in the context of global climate change and the increase in anthropogenic pollution, causing deteriorating water quality in aquatic ecosystems. Previous studies on scum formation mainly focus on the buoyancy-driven floating process of larger colonies, neglecting other potential mechanisms. To study the non-buoyancy-driven rapid flotation of , we here investigate the floating processes of two strains of single-cell species ( and ), which are typically buoyant, under light conditions (150 μmol photons s m).

Dynamics of surface scum formation under different wind conditions: the role of hydrodynamic processes at the air-water interface.

Due to climate change, blooms occur at increasing frequencies in aquatic ecosystems worldwide. Wind-generated turbulence is a crucial environmental stressor that can vertically disperse the surface scum, reducing its light availability. Yet, the interactions of scum with the wind-generated hydrodynamic processes, particularly those at the air-water interface, remain poorly understood.

Effect of extracellular polymeric substances on the colony size and morphological changes of .

Surface blooms of colony-forming are increasingly occurring in aquatic ecosystems on a global scale. Recent studies have found that the colonial morphology is a crucial factor in the occurrence, persistence, and dominance of blooms, yet the mechanism driving its morphological dynamics has remained unknown. This study conducted a laboratory experiment to test the effect of extracellular polymeric substances on the morphological dynamics of .

Selection of photosynthetic traits by turbulent mixing governs formation of cyanobacterial blooms in shallow eutrophic lakes.

Prediction of the complex cyanobacteria-environment interactions is vital for understanding harmful bloom formation. Most previous studies on these interactions considered specific properties of cyanobacterial cells as representative for the entire population (e.g.

Simultaneous Screening and Quantification of 479 Pesticides in Green Tea by LC-QTOF-MS.

A high-throughput screening and quantification method for 479 pesticides in green tea was established based on solid-phase extraction combined with liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Pesticides were extracted from samples using an optimized SPE (TPT cartridges) procedure. LC-QTOF-MS in All Ions MS/MS scan mode acquired full MS data for quantification and product ion spectra for identification.

Differences in survivability and toxic potential among Microcystis colonies of different sizes in sediment.

Microcystis colonies have the ability to persist for extended periods in sediment and function as a "seed bank" for the succeeding summer bloom in water column. The colonial morphology and toxin production ability of Microcystis are important for their population maintenance and life history. However, it is unclear about the influence of the colony morphology and toxic potential of Microcystis colonies on their benthic process.

Instantaneous and reversible flocculation of Scenedesmus via Chitosan and Xanthan Gum complexation.

An instantaneous and reversible flocculation method for Scenedesmus harvesting was developed, based on the complexation of Chitosan (CTS) and Xanthan Gum (XG). Under rapid stirring, Scenedesmus cells formed centimeter-sized flocs within 20 s using binary flocculants of 4 mg/L CTS and 16 mg/L XG. These flocs exhibited a remarkable harvest efficiency exceeding 95 % when filtered through 500-μm-pore-sized sieves.

Promoting heterotrophic denitrification of Pseudomonas hunanensis strain PAD-1 using pyrite: A mechanistic study.

Denitrification is critical for removing nitrate from wastewater, but it typically requires large amounts of organic carbon, which can lead to high operating costs and secondary environmental pollution. To address this issue, this study proposes a novel method to reduce the demand for organic carbon in denitrification. In this study, a new denitrifier, Pseudomonas hunanensis strain PAD-1, was obtained with properties for high efficiency nitrogen removal and trace NO emission.

Effect of light-mediated variations of colony morphology on the buoyancy regulation of Microcystis colonies.

Light is an important driver of algal growth and for the formation of surface blooms. Long-term buoyancy maintenance of Microcystis colonies is crucial for their aggregation at the water surface and the following algal bloom development. However, the effect of light-mediated variations of colony morphology on the buoyancy regulation of Microcystis colonies remains unclear.

Development and Validation of a Method for Determination of 43 Antimicrobial Drugs in Western-Style Pork Products by UPLC-MS/MS with the Aid of Experimental Design.

Western-style pork products have attracted many modern urban consumers, and these products have rapidly entered the Chinese market. The current hazard analysis of processed meat products mainly focuses on processing hazards (PAHs, microorganisms, and food additives), with less attention to veterinary drug residues. According to the survey results, the residues of antimicrobial drugs (sulfonamides and quinolones) in pork and its products in China are a severe problem, which may cause metabolic reactions, toxic effects, or enhance drug resistance.

Multi-residue analysis of 206 pesticides in grass forage by the one-step quick, easy, cheap, effective, rugged, and safe method combined with ultrahigh-performance liquid chromatography quadrupole orbitrap mass spectrometry.

A novel method for detecting pesticide multi-residue in grass forage (alfalfa and oat) was established based on the one-step automatic extraction and purification technology of quick, easy, cheap, effective, rugged, and safe combined with ultrahigh-performance liquid chromatography quadrupole Orbitrap high-resolution mass spectrometry. The crushed sample was extracted with acetonitrile with 1% acetate, followed by a cleanup step with a primary-secondary amine, octadecylsilane, and graphitized carbon black. The extraction and purification were carried out using the one-step automatic pretreatment equipment.

Effects of chronic exposure to microcystin-LR on life-history traits, intestinal microbiota and transcriptomic responses in Chironomus pallidivittatus.

Microcystins (MCs) are the most widely distributed cyanobacterial toxins that can exert adverse effects on aquatic organisms, but aside from the study of the harmful effect of cyanobacterial blooms, little is known about the effect of released MCs on the growth and development of chironomid larvae. To assess the harmful effect and the toxic mechanism of MCs on midges, the life-history traits, intestinal microbiota, and transcriptome of Chironomus pallidivittatus were analyzed after chronic exposure to 30 μg/L of MC-LR. Exposure inhibited larvae body length by 35.

Rapid Screening of β-Agonists in Animal Hair by Thermal Desorption Electrospray Ionization Mass Spectrometry.

Background: Even though the use of β-agonists in livestock has been banned in many countries, β-agonists abuse is still out of control owing to time-consuming and complicated determination techniques.

Objective: This study applied ambient thermal desorption electrospray ionization mass spectrometry (TD-ESI/MS) as a new strategy for rapidly screening seven β-agonists. As it does not require pretreatment, this method allows on-site and real-time detection.

Flexibility of Overwintering Strategy in Response to Winter Temperatures.

is one of the most common bloom-forming cyanobacteria in freshwater ecosystems throughout the world. However, the underlying life history mechanism and distinct temporal dynamics (inter- and intra-annual) of populations in different geographical locations and lakes remain unclear but is critical information needed for the development of robust prediction, prevention, and management strategies. Perennial observations indicate that temperature may be the key factor driving differences in the overwintering strategy.

Effects of microcystin-producing and non-microcystin-producing Microcystis on the behavior and life history traits of Chironomus pallidivittatus.

Species of the genus Microcystis are among the most notorious cyanobacteria in eutrophic lakes worldwide, with ability present adverse effects on many aquatic organisms. In the surface sediments, Microcystis can be ingested by benthic macroinvertebrates such as Chironomus. However, the potential negative effects of Microcystis on Chironomus life history traits remain unclear.

Simultaneous removal of cyanobacterial blooms and production of clean water by coupling flocculation with a rotary drum filter.

A mechanical harvesting technology based on coupling flocculation with a rotary drum filter (RDF, 35-μm) was applied to remove cyanobacterial blooms and produce clean water in Lake Caohai, a sub-lake of Lake Dianchi (Kunming, China). After treatment with a shipboard RDF and cationic polyacrylamide (CPAM, 0.5-2 mg/L) flocculation, > 95% of cyanobacterial biomass was removed.