Papers by Keyword: HPLC

Abstract: This paper establishes the HPLC method of determining three nitrophenol isomers in municipal sewage, surface water and tap water. After the sample is filtered and distilled, conduct the monitoring analysis on the distillate with HPLC-DAD and quantify it in external standard method. In the municipal sewage treated in bioanalysis method one type of target object o-nitrophenol is found, whose content is 0.11mg·L^-1, no target object is found in all the other samples. This method has the adventages of high separation efficiency and high analysis rate. The experiment result shows that the linear correlation coefficient is above 0.983, the recovery rate lies between 78.6% and 105.2%, the minimum detection limit is 0.05mg·L^-1(S/N=3.0).

Abstract: A new simple and efficient RP-HPLC-UV method was developed for the simultaneous analysis of isoflavonoids in Huangqi Gegen and its marketed formulations. Effective chromatographic separation of ten active components was achieved on a Kromasil C₁₈ column (4.6×250 mm, i.d.; 5 μm) with gradient elution of methanol and 0.2% formic acid aqueous solution at a flow rate of 1.0 mL/min in 60 min. Detection was performed at 250nm. The validation of the method included tests of linearity, sensitivity, precision, repeatability, stability and accuracy. All calibration curves showed good linear regression (r>0.999) within test ranges. The established method showed good precision and accuracy with overall intra-day and inter-day variations of 0.77-1.81 % and 1.38-2.47 %, and overall recoveries of 96.64-103.96 % for the compounds analyzed. The developed method was successfully applied for the quantitative analysis of constituents in Huangqi gegen and its marketed formulations.

Abstract: The separation of cypermethrin was studied on Chiralcel OD-H column using the high performance liquid chromatography (HPLC) method. And well distinguished peaks of cypermethrin isomers were obtained. The influences of mobile phase ratios, flow rates, and detection wavelengths on the separation results were investigated. The optimal chromatographic conditions were as follows: the mobile phase ratio was hexane: isopropanol = 97:3, the flow rate was 0.4ml/min, and the wavelength was set as 236 nm. Under the optimal conditions, the resolutions of cypermethrin enantiomers were more than 2.0.

Abstract: This paper established a HPLC method of determining two common types of phenols endocrine disrupter (pEDCs) in municipal sewage, surface water and tap water. After the sample is filtered and distilled, the distillate is detected with HPLC-DAD, and quantified in external standard method. In the municipal sewage, surface water and tap water Bisphenol-A (BPA) and 4-octyl phenol (4-OP) are not found. The experiment result shows the linearly dependent coefficient (R² ) is 0.9914 and 0.9870 respectively, the recovery lies between 89.7-95.6%, the limit of detection is 0.001 (S/N=4.0) and 0.010mg·L^-1 (S/N=2.5) respectively. This method has a high separation efficiency and a rapid analysis speed.

Abstract: In this study, a novel microwave-assisted extraction (MAE) method has been developed for the extraction and determination of the major biologically active compounds, crocin and its seven trans-cis analogues in a traditional Chinese medicine (TCM), gardenia fruits (Gardenia jasminoides Ellis) with analysis by reversed phase HPLC. Sudan I [1-phenylazo-2-naphthol] was selected as the internal standard. The results of quantitative determination of seven crocin analogues in six commercial gardenia fruits samples show that MAE–HPLC is a simple, rapid, low cost and reliable method for the determination of biologically active compounds, crocin analogues in TCM, and also a potential and powerful tool for quality assessment of gardenia fruits (Gardenia jasminoides Ellis).

Abstract: A rapid extraction method involving ultrasound wave and microwave synergistic extraction (UMSE), followed by sample clean-up on a neutral Al₂O₃ cartridge, high performance liquid chromatography (HPLC) with fluorescence detection, was optimized for polycyclic aromatic hydrocarbons (PAHs) determination in Ginkgo biloba extracts (GBE). The optimum extraction conditions of UMSE were carried out with 5 g of GBE and 40 mL n-hexane/dichloromethane (1:1, v/v), on ultrasound wave and microwave simultaneous mode of working for 9 min for one time. The extraction mean recovery of total PAHs amounted to 88.69%. The optimized procedure, that presented good analytical performances could be applied to determine PAH content in GBE.

Abstract: A method was developed for determination of Ethinylestradiol, Diethylstilbestrol, 4-Nonylphenol and Estradiol benzoate residue in fish samples using solid phase extraction and high performance liquid chromatography. Samples were extracted and filtered for HPLC analysis. The analysis was used gradient elution with acetonitrile-water as the mobile phase. Under the optimized conditions, a method with good reproducibility (1.16%~2.45%) and the recovery (80.0%~92.5%) was developed for target components in spiked fish samples. The calibration curves were linear with correlation coefficient ranged from 0.9970 to 0.9983. The detection limit of the method was ranged from 0.0606 to 0.6066μg/ml.This method was rapid, sensitive and nothing interfered determination of the 4 kind of components.

Abstract: HPLC (High Performance Liquid Chromatography) method for danofloxacin(DAN), enrofloxacin(ENR), sarafloxacin(SAR) and difloxacin(DIF) residues in freshwater fish was developed. The fish sample was extracted with methanol-water-acetic acid(2/8/0.01, V/V/V), performed on a C18 solid-phase extraction column. With methanol+malonic acid-magnesium chloride aqueous solution as mobile phase, gradient elution at 30°C, inject volume was 20μL. The wavelength of UV detector was 280 nm. The linear rang of four drugs was 0.1~10μg/mL. In the level of 0.5μg/kg and 4.0μg/kg, the average recovery of the four kinds of drugs was 79.81%~92.03% , the RSD was 1.03%~4.07%. The limit of DAN, ENR, SAR, and DIF was 0.1μg/kg, 0.1μg/kg, 0.05μg/kg, and 0.05μg/kg individual. This method was employed to analyze freshwater fishes, such as catfish, chub and carp, because of its simplicity and high efficiency.

Abstract: Catalpol, an iridoid glycoside, has been verified to be of neuroprotection and may be a potential agent for the treatment of neurodegenerative disease. The extraction technology of catalpol has been tested in this paper. We used different extraction methods including extraction at room temperature (ERT), heat reflux extraction, Soxhlet extraction, ultrasonic extraction and microwave-assisted extraction (MAE) to evaluat the percentage extraction of catapol from Rehmannia glutinosa Libosch. The extracts were analyzed by high performance liquid chromatography (HPLC). Methanol (100%, v/v) extracted high percentage extraction of catapol compared to ethanol (60%, v/v) which achieved the highest percentage extraction of catapol in different concentration of ethanol. The results showed that the percentage extraction of catalpol from Rehmannia glutinosa Libosch by MAE was more efficient in short time followed by ultrasonic extraction, Soxhlet extraction, heat reflux extraction and ERT methods. MAE has need of 4 min, whereas ultrasonic extraction, Soxhlet extraction, heat reflux extraction and ERT techniques require 70, 140, 180 min and 60 h respectively, to leach higher percentage extraction of catalpol. The time taken by MAE was nearly 18 times less than the ultrasonic extraction, 35 times less than Soxhlet extraction, 45 times less than heat reflux extraction and 900 times less than ERT for the highest percentage extraction of catalpol. The present results showed that the high extraction efficiency and considerable saving of time by MAE were more competent than the conventional extraction techniques.

Abstract: In this contribution, a simple and sensitive extraction-cleanup method which was termed MAE-μ-SPE, was developed for the analysis of pharmaceutical and personal care products (PPCPs) in environmental water samples. The PPCPs included bisphenol A (BPA), diethyl phthalate (DEP), dibutyl phthalate (DBP), di (2-ethylhexyl) phthalate (DEHP), tetracycline (TC), deoxytetracycline (DC), oxytetracycline (OTC) and chloroteracycline (CTC). In this method, the PPCPs in the samples were extracted by microwave-assisted extraction (MAE) following adsorbed by copper (II) isonicotinate in micro-solid phase extraction (μ-SPE) device. The PPCPs were determined by high performance liquid chromatography with ultra-violet detector (HPLC-UV). The procedure of the MAE-μ-SPE was optimized in extraction temperature, extraction time, desorption time and desorption solvent. Analytical performances, such as limits of detection (in the range of 2.0-8.5 μg/L), quantification (in the range of 6.6-28.0 μg/L), and repeatability of the over-all procedure (less than 13%) were established. DEP, DBP, DEHP and TC studied in water samples were ranged from 18.2-68.8 μg L^-1, while BPA, OTC, CTC and DC were found all below the detection limit in these samples.