Search

A method of ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) combined with modified QuEChERS purification technology was developed for the simultaneous determination of 25 veterinary medicine residues including four classes (sulfonamides, quinolones, chloramphenicols and amantidines) in chicken and egg. The samples were hydrolyzed by dilute hydrochloric acid, extracted by acetonitrile. Sodium chloride was added into the extracting solution to salt out. The acetonitrile was took out and degreased by n-hexanecyclohexane solution (1∶1,V/V) after stratification of acetonitrile and aqueous phase and concentrated to dry. The residues were dissolved with 0.2% formic acid ethyl acetate to remove the sodium chloride by filtrating and the filtrate was concentrated to dry again, then the sample was purified with a mixture of 30 mg of C18 and 60 mg PSA after adding 0.2% formic acid methanol. The target compounds were separated by ZORBAX C18 chromatography column (50 mm×2.1 mm×1.8 μm), the mass spectrometer data were acquired under multiple reaction monitoring (MRM) of positive and negative modes at the same time, and the residues were quantitated by isotope internal standard method. The results showed that the linear of 25 veterinary medicines is good in the range of 0.2~250 μg/L. The linear correlation coefficients are more than 0.99, and the detection limits are in the range of 0.1~0.9 μg/kg. The limits of quantification are 0.3~3.0 μg/kg. The average recoveries at three spiked levels (about 1, 5 and 20 folds of quantitative limits) are 79.5%~119% with the relative standard deviations of 0.9%~9.2%. The method is rapid,simple, accurate, sensitive and cheap, which is suitable for simultaneous determination of multiple vererinary medicine residues in eggs and chicken.

Hypercrosslinked porous polymers have become a hotspot of research by virtue of their high specific surface area, mild synthesis conditions, and wide source of monomers, which are promising adsorbents for water treatment. In this paper, 4-vinylbenzylchloride (VBC), acrylic acid (AA) and divinylbenzene (DVB) were used to prepare crosslinked microspheres as a template by reflux precipitation polymerization. On this basis, porous microspheres were prepared by hypercrosslinking reaction using FeCl3 as catalyst. Next, excess FeCl3 was used as iron sources for the next solvothermal reaction to prepare magnetic hypercrosslinked P(VBC-DVB-AA)@Fe3O4 microspheres (MHCPMs). The elution step of the hypercrosslinked product was omitted, while magnetic Fe3O4 was introduced. MHCPMs have uniform particle size, high specific surface area, superparamagnetism and abundant functional groups. After synergistic preparation, the specific surface area of the MHCPMs-60 was still as high as 654.56 m2/g, and the saturation magnetization strength reached 29.0 eum/g. The magnetic microspheres could be directly aggregated and separated in the presence of an applied magnetic field. In addition, MHCPMs were well dispersed in water after vigorous shaking and could be used to adsorb the cationic dye quickly and efficiently. The adsorption results for methylene blue (MB) well conformed to the Langmuir model (R2 = 0.999) with a maximum adsorption of 214.26 mg/g and followed the pseudo-first-order kinetic model. In addition, the MHCPMs-60 showed good reusability and stability over seven cycles. Therefore, this study proposed a synergistic strategy for the preparation of magnetic porous polymer microspheres, which exhibited a significant potential application value in many fields. [ABSTRACT FROM AUTHOR]

Objective: To explore the main factors of renal function injury caused by the combination of elemene emulsion injection in the real world. Methods: Based on the hospital information system medical database constructed by the Institute of Clinical Basic Medicine of Chinese Academy of Traditional Chinese Medicine, taking the patient information of elemene emulsion injection used in 21 top three hospitals in China as the research object, the nested case control study method was used to compare the combined medication of patients with renal function injury group and control group, The main factors that may lead to renal function injury were screened by MCP variable selection method, and the above main factors were further analyzed by classical logistic regression and propensity score logistic regression method. Results: The analysis found that the combined use of potassium chloride within 7 d before the use of elemene emulsion injection or the combined use of furosemide during the use of elemene emulsion injection may be the main factor leading to renal function injury. Conclusion: The combination of elemene emulsion injection and the above main factors that may lead to renal injury should be avoided. If it must be used, clinical monitoring should be strengthened, and abnormal reactions should be treated immediately. The results of this study have certain clinical significance, and the clinical mechanism can be further studied and explored in the future. [ABSTRACT FROM AUTHOR]