Notes

Reaching two-dimensional visual spectroscopy using temporary and spectral resolution employing massive matted about three photons.
freshwater fish, were procured from a supermarket and a farm product market. The results of the positive samples were consistent with those observed with the standard methods. The method described herein is easy to operate, sensitive, and accurate. It is suitable for the simultaneous and rapid determination of various prohibited and restricted veterinary drug residues and metabolites in animal-derived foods.Lipophilic shellfish toxins pose significant threats to the health of seafood consumers and public health. The symptoms of these kinds of toxins include severe diarrhea, abdominal cramps, nausea and gastrointestinal disorders. These symptoms could be hardly distinguished with many other symptoms of food poisoning and diseases. Therefore, a fast and accurate determination method in human biological samples is urgently needed for the accurate judgement of food poisoning incident, which is important for the investigation of public health emergencies and clinical treatment of poisoned patients. However, there were several flaws of the previous studies reported on the analysis of lipophilic shellfish toxins (1) limited target compounds were covered; (2) the pre-treatment process was complex; (3) the sensitivity of the compound was low. In this study, a simple extraction method coupled with ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determin 12 compounds were in the range of 72.7%-124.1% at three spiked levels (i. e., LOQ, three times LOQ, and ten times LOQ). The intra-day and inter-day precisions were 2.1%-20.0% and 2.1%-15.3%, respectively. The method was applied in the detection of the 12 lipophilic shellfish toxins in the urine and plasma samples of healthy humans and mice previously injected with the 12 shellfish toxins intraperitoneally. None of the 12 toxins were found in the samples from healthy human, while all of the 12 lipophilic shellfish toxins were found in the urine and plasma samples collected from the poisoned mice in the range of 1.14-2.35 μg/L and 1.01-1.17 μg/L, respectively. The established method has the advantages of sensitive, quick, easy to operate, and of low sample volume. It can be used for the simultaneous determination of 12 lipophilic shellfish toxins in urine and plasma samples.Urine is an important source of biomolecular information for metabolomic studies. However, the acquisition of high-quality metabolomic datasets or reliable biomarkers from urine is difficult owing to the large variations in the concentrations of endogenous metabolites in the biofluid, which are caused by diverse factors such as water consumption, drugs, and diseases. Thus, normalization or calibration is essential in urine metabolomics for eliminating such deviations. The urine osmolality (Π), which is a direct measure of the total urinary solute concentration and is not affected by circadian rhythms, diet, gender, and age, is often considered the gold standard for estimation of the urine concentration. In this study, a pre-data acquisition calibration strategy based on osmolality was investigated for its feasibility to overcome sample concentration variability. Before data acquisition, the product of the osmolality×injection volume of all samples was set to be equivalent through the uses of a customized injey controls. As a concentration estimator, osmolality showed better linear correlation with the mass signal and was less influenced by physiological or pathological factors, thus obtaining broader application and more accurate results than creatinine. The concentration variability was effectively eliminated after customized dilution calibration and showed a more obvious clustering effect in the PCA score plot. The OPLS-DA-based statistical model used to identify discriminate metabolites was improved, with less chance of overfitting. In conclusion, the calibration strategy based on osmolality combined with total ion abundance or MSTUS normalization significantly overcame the problem of urine concentration variability, eliminated intra-group differences, and possessed better parallelism, thus giving better clustering effects in PCA or OPLS-DA and higher reliability of the statistical model. The results of this study provide guidance and a reference for future metabolomic studies on urine.Protein phosphorylation is an important type of post-translational protein modification. In Western Blot experiment, the assay of phosphoproteins need special phospho antibodies, which are expensive, difficult to preserve, poorly reproducible. To this end, the immobilized metal ion affinity luminescent silica nanoparticles for instead of phospho antibodies were prepared. A layer of polymer was created on the surface of the silica nanoparticles via co-polymerization to protect the nanoparticles and to functionalize them with the immobilized metal ion affinity property to specifically label the phosphorylated proteins in Western Blot assays. The affinity luminescent silica nanoparticles were prepared with the following procedure. First, the sol-gel precursor fluorescein isothiocyanate-3-aminopropyltriethoxysilane (FITC-APTES) with the fluorescent moiety was prepared by modifying APTES with FITC. The luminescent silica nanoparticles (FITC@SiO2) were synthesized using the Stöber synthesis method in a reversed micicles, while the bovine albumin band could not be labelled. This indicates that the luminescent FITC@SiO2-MPS-GMA-NTA-Ti4+nanoparticles can be used to label the phosphorylated proteins in Western Blot experiments.The ratio of stable isotopes of the elements in explosives differs depending on the raw materials obtained from different geographical sources or the production processes adopted. Hence, this ratio can be used as an important index for the comparison and trace of explosives. Isotope ratio mass spectrometry (IRMS), a high-precision method for the analysis of stable isotope ratios, has evolved into a mature tool in this regard. In combination with elemental analysis, gas chromatography, liquid chromatography, etc., IRMS is widely used in food safety, environmental protection, forensic science, and other fields. IRMS also plays an important role in the comparison and trace of explosives. Since its application to distinguish trinitrotoluene (TNT) produced in different countries in 1975, IRMS has been successfully used in the analysis of various explosives. Selleckchem FX11 However, there is no systematic summary on the research progress on the stable isotope ratio analysis of common explosives. This paper provides a brief description of the related principle, instrumental composition, and characteristics of stable isotope ratio analysis.
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