Fitchneergaard7259

-1-propanol was longer than that of R-1-phenyl-1-propanol, while for the other enantiomers, the peak time of the R-enantiomers was longer than that of the S-enantiomers.Squama Manis, or "Chuanshanjia" in Chinese, is a traditional Chinese medicine (TCM) for promoting blood circulation and reducing swelling and discharge; the only animal source used in TCM is the scales of Manis pentadactyla. However, in today's pharmaceutical market, there are many scales from other species of the same genus that are difficult to distinguish from Squama Manis. High-quality and low-quality scales are also severely confused. To solve the above problems, various analytical methods have been developed, such as thin-layer chromatography, mass spectrometry and DNA detection. Owing to their low resolving ability, high equipment cost, and inconvenient operation, none of these methods are appropriate for routine identification of Squama Manis. A chromatographic fingerprint can comprehensively reflect the synergic action of multiple chemical compositions in TCM and has been widely used for the quality control of TCM. In the present study, we established a fingerprint of Squama Manis and explored its feurce identification and quality determination by combining different data analysis methods. The established strategy may provide a new method for improving the the validity and accuracy of Squama Manis in clinical use.As a rich source of high activity antioxidant peptides, Scomberomorus niphonius is a key marine natural product with a high processing value. Due to the high complexity of fish tissues, high recovery extraction and high efficiency screening of the active antioxidant peptide species have become the major challenges for the research and development of preparation and separation techniques. Due to the high specificity of hydrolytic enzymes, when different types of enzymes are used for the hydrolysis of fish tissues, the resultant active peptides may have significant differences in chemical structures, biological functions, and physical activities. In this study, in order to obtain antioxidant peptides with high activity and functionality, defatted visceral powder of Scomberomorus niphonius was used as a raw material for sample preparation. Five hydrolytic enzymes (flavor protease, trypsin, acid protease, neutral protease, and alkaline protease) were selected and investigated for their hydrolyzing efficiencies in were separated, collected, freeze-dried, and finally tested for their antioxidant capability. The results showed that the strong cation exchange phase was more suitable for antioxidant peptide isolation and purification from Scomberomorus niphonius viscera, and an antioxidant peptide component with high activity was successfully screened. During the activity test, the 50% inhibition concentration (IC50) value of the DPPH· scavenging capability of this peptide was 0.672±0.051 mg/mL, which was 13.6 times higher than the activity value before the peptide species was purified. The current study for the first time reports the application of high performance nano flow liquid chromatography in the purification and analysis of antioxidant peptides from a marine natural product source and also demonstrates the effectiveness and future prospect of the use of nano flow ion exchange chromatography for high performance separation and high efficiency screening of antioxidant peptides.A rapid and accurate analysis method based on ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight high-resolution mass spectrometry (UPLC-Q-TOF-HRMS) was developed to screen and determine nine antiallergy drugs in emulsion cosmetics. First, a standard library of the target compounds was established. The library contained the TOF-MS information and secondary MS information such as retention time, ion addition mode, mass error, isotope distribution, mass-to-charge ratio of the parent ion, and fragment ion distribution. According to the European Union regulation (SANTE/11945/2015), the standard for the qualitative determination by HRMS was determined; that is, each compound was confirmed by two ions with a mass error below 5%, and the abundance ratio of the two ions was less than 30%. Second, the instrument conditions and sample pretreatment conditions for the determination of different compounds were optimized, and the influence of different levels of quantitative ions on the mat directly after allowing it to pass through the column, without any subsequent washing and elution procedures. In addition, the LOQs of this method are lower than those of other LC-MS/MS methods, indicating that the proposed method has higher sensitivity. selleck compound The application of SWATH data acquisition makes it possible to achieve quantification with two pairs of product ions, thus reducing the matrix effect and ensuring accuracy of the quantitative results. Therefore, the proposed method is less time-consuming and operationally convenient, and it can be used for the rapid screening and accurate quantification of antiallergics in lotion samples.In the aquaculture industry, fluoroquinolones are widely used as effective therapeutic agents to prevent animal diseases. The wide bactericidal activity of fluoroquinolones strongly depends on their concentration. Abuse of fluoroquinolones is considered the main reason for the possible occurrence of residues in aquatic products. The increasing presence of residues in aquatic products may pose potential risks to human health. Therefore, it is important to develop an efficient, sensitive, and reliable method for the simultaneous determination of fluoroquinolones in aquatic products. In the analysis of fluoroquinolones, many HPLC methods with different detection techniques have been applied. Among the most common used techniques, HPLC-MS is possible for the determination of very low level analytes in matrix. For the determination of low concentrations of fluoroquinolone residues in aquatic products, preliminary extraction and purification steps are frequently needed to achieve low detection limits. Accelerated se preparation of the magnetic purification material, automated and simple operation, high sensitivity, short extraction time, and less solvent consumption. This sensitive, repetitive method could be successfully employed for the determination of ten fluoroquinolone residues in aquatic products, with good recoveries.Based on ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-QTOF-MS), UNIFI 1.7.0 software was used to establish a screening and confirmation method for the analysis of 91 pesticide residues, which was qualitatively validated and applied to tea screening in the circulation market. By analyzing the collected pesticide certified reference materials (CRM), a mass spectral database of 91 pesticides was constructed. The database contains multiple types of information, including formulas, theoretical exact masses, retention times, characteristic fragment ions, and adduct types. The samples were extracted with acetonitrile, purified on a solid-phase extraction column, and separated on an Acquity BEH C18 column. All the data (ESI+) were acquired in MSE mode and analyzed using the UNIFI information system. Analyte detection was based on the retention time deviation ±0.1 min, accurate mass deviation ±5×10-6, and major adduct forms including[M+H]+,[M+Na]+,[M+K]+, and[M+NH4]+. Screecreening tests. Finally, the established method was used to analyze the pesticide residues in 22 tea samples available on the market. Six pesticide compounds were found in the tea samples, all of which were confirmed to be positive after artificial identification. This method provides a reference for the high-throughput screening and detection of pesticide residues in tea as well as a research approach for the analysis of various chemical contaminants in other matrices.Streptomycin (STR) and dihydrostreptomycin (DSTR) are two of the most common aminoglycoside antibiotics used in veterinary medicine. STR is produced by some streptomyces griseus strains, and DSTR is a derivative of STR. In recent years, STR has been widely used in grapes to induce denuclearization. However, high levels of STR may have adverse effects like serious ototoxicity and nephrotoxicity. Therefore, to ensure the quality of grapes and the health of consumers, the regulation of STR and DSTR levels in grapes is required. An analytical method was developed for the identification and quantification of STR and DSTR in grapes by liquid chromatography-tandem mass spectrometry (LC-MS/MS). STR and DSTR are highly polar compounds due to the presence of various amino and hydroxyl groups in their structure. The determination of STR and DSTR poses a considerable analytical challenge, both during sample preparation and instrument analysis. In this study, the main factors governing the response, recovery, and sensitivan ion-pair additive in the mobile phase to increase their retention, which is known to cause severe contamination of the column and serious ion suppression with electrospray ionization detection. In addition, the ideal enrichment and purification effect can be achieved by adding a sodium 1-hexane sulfonate solution to the superstratum extract with the use of only Oasis HLB for sample treatment. The method described herein has the advantages of easy operation, accuracy, and selectivity, making it feasible for the identification and quantification of STR and DSTR residues in grapes.The presence of 3-chloro-1,2-propanediol fatty acid esters (3-MCPDE) in food and processed materials has recently become a topic of concern because of the toxicity of their metabolites. 3-MCPDE structurally similar to glyceride, which makes it difficult to separate or extract them from oils and fritters. A method based on ultra performance convergence chromatography-tandem mass spectrometry (UPC2-MS/MS) was established for the determination of 15 3-MCPDE in vegetable oils and fritters. Amino-packed columns were used to purify the samples. The analytical conditions were optimized, and the matrix effect was investigated. The sample was treated by column chromatography to remove glyceride and free fatty acids, which induce strong matrix effects. The amino-packed column was eluted with hexane and hexane-ethyl acetate (64, v/v). Every 1 mL of the eluent was analyzed using a UPC2 and ACQUITY QDa detector. Elution curves were drawn based on the testing data and used to determine the collection volume. The collectiontion of monoesters, for example, via derivatization.Bisphenols are important industrial raw materials that are widely used to produce plastic bottles (feeding bottles), infant cups, and food and beverage (milk powder) cans. Because of the estrogen-like effect of bisphenols, even low-dose intake of these compounds by trace migration affects normal hormone levels in the human body. Therefore, it is imperative to develop a rapid, accurate, and highly sensitive method for the determination of bisphenols in serum. In this study, methyl tert-butyl ether (MTBE) was used as the extraction solvent, and the liquid-liquid extraction pretreatment method was used for sample processing. A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established for the simultaneous determination of bisphenol A (BPA), bisphenol B (BPB), bisphenol F (BPF), and bisphenol S (BPS) at trace levels in infant serum. The important parameters affecting the extraction efficiency, such as the extraction solvent, extraction time, and extraction solvent volume for the four bisphenol environmental hormones were optimized.