Taylorsmith9091

In the current study, Pesticide residue extraction in beeswax was carried out using a mixture of acetonitrile-ethyl acetate (13, v/v). This mixture of solvents not only enables the melting of beeswax sample at a lower temperature than when using acetonitrile only but also introduces one phase solution. The sample extract was directly injected into both GC-MS/MS, of the commonly used split-less inlets, and into LC-MS/MS. Sample preparation and clean-up were also optimized. The developed method was validated according to SANTE/11813/2017 European Union guidelines. Three spiking levels of low concentrations 20, 50, 100 µg/kg were studied for the analysis of a total of 373 pesticides. Most of the studied pesticides have acceptable recovery between 80 and 110% with good reproducibility less then 10. There are 265 and 139 pesticides having a lower limit of quantifications equal 20 µg/kg using LC-MS/MS and GC-MS/MS, respectively. Finally, the developed method was successfully applied for the analysis of real beeswax samples. Three normal phase HPLC methods were produced to separate lipid classes on a PVA-Sil stationary phase including 9 polar lipids (method 1); 13 combined polar and neutral lipids (method 2); and a combined method that further separates the neutral lipids into 2-4 subclasses based on the presence of fatty acids containing a polar functional group (e.g. hydroxyl) for a total of 20 lipid classes and subclasses separated in a single run (method 3). Polar lipids separated include the phosphoglycerolipids PG, PE, PI, PS, PC and LPC; the galactoglycerolipids MGDG and DGDG; and a sulfoglycerolipid SQDG. Neutral lipids include TAG, DAG, and MAG classes and sub-classes containing 0-3, 0-2, and 0-1 hydroxy fatty acids, respectively. selleck chemicals The hexane/isopropanol/methanol/aqueous system separates polar lipids without the use of chloroform such that it is suitable for radioactivity analysis by in-line flow scintillation counting. Each method was optimized using the natural lipid standards comprised of diverse molecular species that were detected by ELSD. All molecular species of each lipid class eluted together as single peak detected by ELSD. The methods were demonstrated to be suitable for resolving lipid extracts from animal, microbial, and plant sources as well as application to 14C based metabolic tracing of lipid metabolism in leaves and seeds. As part of the "omics" technologies in the life sciences, metabolomics is becoming increasingly important. In untargeted metabolomics, unambiguous metabolite identification and the inevitable coverage bias that comes with the selection of analytical conditions present major challenges. link2 Reliable compound annotation is essential for translating metabolomics data into meaningful biological information. Here, we developed a fast and transferable method for generating in-house MS2 libraries to improve metabolite identification. Using the new method we established an in-house MS2 library that includes over 4,000 fragmentation spectra of 506 standard compounds for 6 different normalized collision energies (NCEs). Additionally, we generated a comprehensive liquid chromatography (LC) library by testing 57 different LC-MS conditions for 294 compounds. We used the library information to develop an untargeted metabolomics screen with maximum coverage of the metabolome that was successfully tested in a study of 360 human serum samples. The current work demonstrates a workflow for LC-MS/MS-based metabolomics, with enhanced metabolite identification confidence and the possibility to select suitable analysis conditions according to the specific research interest. A simultaneous extraction and cleanup method was optimized and validated for the determination of 40 antibiotics from cephalosporin, fluoroquinolone, lincosamide, macrolide, nitroimidazole, quinolone, sulfonamide and tetracycline groups in sediments by liquid chromatography with tandem quadrupole mass spectrometry (LC-MS/MS). The method involved hydration of freeze-dried sediment sample (2.0 g) with 2.5 ml of 0.1 M Na-EDTA McIlvaine buffer and extraction with 5 ml of MeOH and MeCN (13 v/v) followed by dispersive solid phase extraction by using 100 mg mix of C18 and PSA (12 w/w) and 50 mg MgSO4 prior to LC-MS/MS analysis. The method was validated for 10, 20, 50 and 100 µg/kg spiking levels by using blank sediment sample obtained from a drinking water reservoir according to the guidelines of European Commission Decision (2002) 2002/657/EC. The method produced clean extracts with generally low matrix effect during LC-MS/MS analysis. The mean recoveries ranged between 24-162%, 48-151%, 51-159%, and 50-149% for 10, 20, 50 and 100 µg/kg spiking levels, respectively, with acceptable precision. The analytical method was sensitive enough to achieve 0.01-34.3 µg/kg and 0.03-115 µg/kg limits of detection and quantitation, respectively. The scope of the method was demonstrated by analyzing complex solid environmental matrices (chicken manure, swine manure, poultry feed and soil) spiked at 10, 20, 50 and 100 µg/kg levels. The method was also applied for the antibiotic analysis in samples with incurred residues. Different matrices in the order of the magnitude as sediments  less then  poultry feed  less then  swine manure  less then  soil  less then  chicken manure were detected with the residues of fluoroquinolone, macrolide, sulfonamide and tetracycline antibiotics. Marine parasites of the genus Parvilucifera have been described as endoparasitoids of dinoflagellates. Recently, the species Parvilucifera corolla was described, but its host range was not examined. Here, the host selectivity of P. corolla was screened, including 110 strains of dinoflagellates (24 genera) and other microalgal groups as potential hosts. Infections and the full life cycle of the parasitoid were observed in 73 strains (16 genera) of dinoflagellates. Parvilucifera corolla did not infect most chlorophytes, cryptophytes, chrysophytes, diatoms, haptophytes and raphidophytes but one strain of Pyramimonas (chlorophyte) was infected, although without viable sporangia. In Symbiodinium natans, a transition to the coccoid stage was induced above a certain parasitehost ratio. These results confirm P. corolla as a generalist parasitoid of dinoflagellates, with important differences in host range regarding other species of the genus. Testate amoebae are a widely-used tool for palaeohydrological reconstruction from peatlands. However, it has been observed that weak idiosomic siliceous tests (WISTs) are common in uppermost peats, but very rarely found as subfossils deeper in the peat profile. This taphonomic problem has been noted widely and it has been established that WISTs disaggregate and/or dissolve in the low pH condition of ombrotrophic peatlands. Here we investigate the effect of this taphonomic problem on water-table reconstructions from thirty European peatlands through the comparison of reconstructions based on all taxa and those with WISTs removed. In almost all cases the decomposition of WISTs does not introduce discernible bias to peatland water-table reconstructions. However, some discrepancy is apparent when large abundances of Corythion-Trinema type are present (9-12 cm deviation with 50-60% abundance of this particular taxon). We recommend that WISTs should be removed before carrying out water-table reconstructions, and that the minimum count of testate amoebae per sample should exclude WISTs to ensure the development of robust reconstructions. Polymeric photocatalysts are promising candidates for water purification, however their catalytic performance are still unsatisfactory due to the fast charge recombination that leads to low reactive oxygen radicals production. In this study, a conceptual energy-transfer-mediated photocatalytic oxygen activation system over polymeric carbon nitride without the need of electron-hole separation is proposed, exhibiting remarkable singlet oxygen triggered bacteria inactivation performance as well as organic pollutants degradation. By structure and excitonic effect modulation, the oxygen activation process changes from the traditional electron-transfer mechanism to the final energy-transfer pathway, leading to the selective generation of singlet oxygen with high efficiency. The generated singlet oxygen is found to fervently attack the bacteria membrane, creating irreparable pores or holes on the cell membrane for cytoplasmic contents leaking out to accelerate bacteria destruction. The work demonstrated here offers a new photocatalytic oxygen activation pathway for achieving high-efficient reactive oxygen species generation performance without the need of charge separation. Cyanobacteria blooms and micropollutants (e.g., antibiotics) in source waters are two increasing environmental issues worldwide. link3 This study hypothesized that the coexisting antibiotics may possibly alter the efficiency of water treatment processes through affecting the physiological and biochemical characteristics of cyanobacterial cells. A toxic strain of Microcystis aeruginosa was exposed to the common antibiotic erythromycin (ERY) at environmentally relevant concentrations; then, samples were collected on days 1, 4 and 6 to assess the efficiency of potassium permanganate (KMnO4) in cyanobacteria oxidation. The percentage of intact cells remained constant after treatment with 2 mg L-1 KMnO4 in M. aeruginosa samples dosed with 0-5.0 μg L-1 ERY. Although 6 mg L-1 KMnO4 could damage cyanobacterial cells, its ability was considerably reduced as the concentrations of ERY increased. KMnO4 oxidation degraded the intracellular microcystins (MCs) in all of the cyanobacterial samples, even the samples with intact cells, possibly resulting from the stimulation of intracellular reactive oxygen species (ROS). The highest amounts of total MCs remained after oxidation with 2 and 6 mg L-1 KMnO4 in 0.2 μg L-1 ERY-treated cyanobacterial samples, which may be due to large amounts of MC production. The 5.0 μg L-1 ERY inhibited the growth of cyanobacterial cells and downregulated the expression of the MC synthesis gene (mcyB), which resulted in the lowest amounts of total MCs. However, it led to the highest concentration (4.6 μg L-1) of extracellular MCs after treatment with 2 mg L-1 KMnO4 for 300 min. Generally, this study indicates that the effectiveness of KMnO4 oxidation in cyanobacteria treatment decreased when the concentration of ERY increased. Hence, the possible risks caused by the coexistence of cyanobacteria and antibiotics, such as reduced efficiency of water treatment processes in cyanobacteria inactivation and degradation of the dissolved MCs, need to be taken into account. Solar-driven interfacial water evaporation, which gets rid of the limitation of saline waters, enables to supply potable water in the worldwide, especially in remote areas where only solar energy and water are available. This technique has also exhibited great potential applications in fields such as seawater desalination, steam sterilization, and fuel production. However, the evaporation efficiency decreases during continuous operation in saline water due to the blockage of the solar absorber resulting from crystalline salt deposition. Therefore, it is still a great challenge to design a stable and efficient solar-driven interfacial saline water evaporator. Herein, a variety of structural designs and engineering strategies for salt removal of evaporators in the latest years were reviewed. We classified these strategies as remaining unsaturated evaporation of saline water, preventing salt ions from contacting the solar absorber, dissolving and/or migrating back of crystalline salts, and keeping salt crystallization away from evaporation area.