Papers by Keyword: SPE

Abstract: Solid polymer electrolyte (SPE) is a safer alternative to use than liquid electrolytes. This research focuses on the highest conductivity with fly ash filler in solid polymer electrolyte (SPE) based on corn starch, using the solution casting method. The crystallinity and interaction between fly ash and Na⁺ ions of solid polymer electrolyte were seen by X-ray Diffraction (XRD), then Fourier Transform Infra-Red (FTIR), showing a shift in functional groups due to the interaction of SiO₂ in fly ash and Na⁺ ions, and surface morphology forms was observed by Scanning Electron Microscopy (SEM). Ionic conductivity was analyzed by Electrochemical impedance Spectrometry (EIS). solid polymer electrolyte with fly ash showed the highest ionic conductivity 2,51 x 10^-4 S/cm, at room temperature with addition fly ash 10%. the highest conductivity result was corresponding with amorphous peak with same concetration on XRD. SPE based on corn starch with Fly ash filler has potential to be used as a solid polymer electrolyte in supercapacitors.

Abstract: Analysis of organic acids in natural water samples using by the distillation followed by the SPE procedure at Strata-X and GC-MS of trimethylsilane derivatives. Influence of distillation and elution, as well as a cartridge housing material, on the compounds recovery was discussed. Data on organic acids in some natural samples are provided.

Abstract: In this study, a rapid and selective method has been developed to determine PENG residues in waste penicillium chrysogenum by using SPE cleanup strategy followed by HPLC. Furthermore, some parameters which influenced the extraction efficiency including extraction mode, solvent and time, while washing solution and eluting solution for SPE were systematically investigated. It should be noted that the extraction process was carried out in a single step by mixing the extraction solvent acetonitrile: formic acid in aqueous solution and chrysogenum samples under ultrasound. The SPE procedure was conducted using Oasis HLB as the clean up cartridge, n-hexane as washing solution, and mixture of acetonitrile and methanol as eluting solution. Under the optimized conditions, the linear of PENG are in the range of 0.1-2000 μg/mL, with the correlation was R²>0.99. In addition, the recoveries of PENG in these samples at three fortification levels of 800-1800mg/kg were 74.98% to 113.47% are obtained, respectively. Moreover, a limits of detection (0.006 mg/kg) and quantification (0.02 mg/kg) could be achieved.

Abstract: A simple and rapid SPE-HPLC/PDA method has been developed for the quantitative determination of tetracyclines in soils. An ultrasonic extraction system for the soil samples was confirmed as a combination of a 1:2 ratio of EDTA-McIlvaine buffer solution with methanol by comparing the extraction efficiency of 4 solvents and optimising the combination ratio. The soil extracts were purified and concentrated by Oasis-MAX cartridge followed by HPLC separation and PDA detection. The optimal chromatographic condition effectively separated the object and interfering substance, which can improve the sensitivity of the instrument. The limits of detection were lower than 20 μg·kg^-1, and the limits of quantification were no more than 60 μg·kg^-1 for all compounds in the soil. The recoveries of tetracyclines peaked at levels of 50-500 μg·kg^-1 and averaged at 62.1% to 108.9% with relative standard deviation values of less than 5%. This method was applied to analyse real soil samples from suburban Beijing farmland, and TC and OTC residues were detected in the soil.

Abstract: Porous microspheres, copolymers: bis [4(2-hydroxy-3-methacryloyloxypropoxy)-phenysulfide (BES.DM) and glycidyl methacrylate (GMA) have been prepared by suspension-emulsion polymerization. The copolymer (BES.DM+GMA) including reactive epoxide rings was modified with three amines: butylenediamine (BDA), diethylenetriamine (DETA), triethylenetetramine (TETA). Next, attachment of HCO₃- species to the primary amine groups took place.The prepared porous polymers were used as adsorbents in off-line SPE experiments. A mixture of phenol (PH), 2-chlorophenol (ChP), 2,4-dichlorophenol (DChP) and 2,4,6-trichlorophenol (TChP) as testing compounds was applied.Depending on the way of chemical modification, the prepared adsorbents possessed diverse sorption properties towards the testing compounds. Competition of the phenolic compounds for active sites presented on the polymer surface was observed. The most effective in water purification process were polymers possessing both amine and bicarbonate groups. The best recovery results were obtained for 2,4-dichlorophenol.

Abstract: In this study, the feasibility of single-walled carbon nanotubes (SWCNTs) as solid-phase extraction (SPE) adsorbent for the determination of bioactive crocin analogues in the traditional Chinese Medicine (TCM) of Gardenia Jasminoides Ellis prior to HPLC analysis was studied. Various experimental factors influencing SPE efficiency and HPLC conditions were studied. By using SWCNTs as the SPE adsorbent, the detection limit of 1.19-2.21 fmol (at S/N of 3) were achieved with the preconcentration efficiency of more than 120-folds, indicating this proposed method was very practical for increasing the sensitivity prior to HPLC analysis, and it may provides useful clue for the efficient extraction for the bioactive compounds in TCMs.

Abstract: A simple and effective extraction method based on solid-phase extraction (SPE) was developed to determine chlorothalonil, metalaxyl, triadimefon, dimetachlone, procymidone, flumetralin, oxadixyl and iprodione in Panax Notoginseng using gas chromatography-mass spectrometry with selected ion monitoring (GC/MS, SIM). The prepared samples were analysed with GC-MS in the selected ion monitoring mode (SIM) using one target and two or three qualitative ions for each analyte. In the method, hexane - dichloromethane（6:4，v/v）was selected to effectively extract the pesticides from the Panax Notoginseng samples. Solid-phase extraction was carried out using Supelclean ENVI-Carb/NH2 SPE Column with acetonitrile-toluene (3:1, v/v) as the eluted solvent. In the linear range of each pesticide, the correlation coefficient was R2≥0.99. The limit of detection ranged from 0.001 to 0.05 µg.mL-1, average recoveries ranged from 79.80% to 95.00%, with relative standard deviations between 1.96% and 4.32% for all 8 pesticides.They were readily achieved with this method for all tested pesticides.

Abstract: Three new hypercrosslinked polymers were used as solid phase extraction packings to enrich Chlortetracycline (CTC) in water. Through the comparison, the NDS-1 column has higher performance than the other two, almost the same as commercial columns HLB on the enrichment of the Chlortetracycline.

Abstract: The polyacrylamide hydrogel (PAMG) has been used in cosmetology in China, Ukraine and Russia since 1990s. Because the monomer acrylamide(AM) used to produce PAMG has been implicated as a potential mutagen and reproductive toxicant[1,2], it is important to accurately determine the amount of residual AM monomer in the PAMG. In this study, a quick, practical and simple method to determine AM is presented with respect to the hydrogel. AM is analysed quantitatively by ODS-3 column with ultraviolet (UV) absorbance detector. AM is separated from interferential component with an aqueous solution of 0.9%NaCl (NS) adjusted at pH~3.7 using hydrochloric acid and then detected at a UV wavelength of 210 nm. The results show that ODS-3 is effective approach for quantifying AM concentrations in PAMG. This method has a lower detection limit of 0.003µg/ml and a linear response range of 0.003 and 0.9 µg/ml (depending on the range required for analysis). Precision studies give coefficients of variation of <3.2%(n=5) for 0.003µg/ml. The recoveries for this method are greater than 90%. When AM content in PAMG is lower than the detection limit of this method, SPE (solid phase extraction) could be used to concentrate AM. In the case, C18 cartridge is used. And the recoveries are about 70% for SPE when AM concentration is lower than ppb.