共查询到20条相似文献,搜索用时 0 毫秒
1.
Anika Pecavar Andrej midovnik Duan Milivojevic Mirko Proek 《Journal of separation science》1997,20(12):674-678
A reversed-phase HPLC method for the analysis of cephalexin (7-[(aminophenylacetyl)amino]-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid) by isocratic separation is described. A comparison is made between the ultrafiltration land the extraction procedure developed in our laboratory. The extraction procedure, based on the deproteinization of plasma with perchloric acid followed by the extraction with dichloroethane and separation of cephalexin on a reversed phase column, gave better recovery. Quantitative validation of our method has been performed by an external standard technique. The relative standard deviations were between 1.1 and 1.9% in the within-day assay and between 1.2 and 2.2% in the inter-day assay. The limit of detection was 0.14ug/ml and the limit of quantification was 0.28ug/ml. This method is rapid, sensitive, simple, and reproducible. The LC MS/MS technique was successfully used for identification and quantification of cephalexin in human plasma samples. 相似文献
2.
A validated high performance liquid chromatographic method was developed for the determination of chromium picolinate in pharmaceutical dosage forms. The analysis was performed at room temperature using a reversed-phase Supelcosil LC-18 (250 x 4.6 mm, 5 microm) column. The mobile phase consisted of acetonitrile:water (40:60 v/v) at a fl ow rate of 0.8 mL/min. The UV-detector was set at 264 nm. The developed method showed a good linear relationship in the concentration range from 0.125 to 12.5 microg/mL with a correlation coefficient from 0.999. The limit of detection and limit of quanti fi cation were 0.091 and 0.181 microg/mL, respectively. 相似文献
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反相高效液相色谱同时测定复方降压药中三组分 总被引:2,自引:0,他引:2
建立了一种反相高效液相色谱法 ,用于同时测定复方降压药中三组分。采用YWGC1 8柱 ,以甲醇 醋酸 醋酸钠缓冲液 水 ( 60∶2 0∶2 0 )为流动相 ,流速为 0 .8mL·min- 1 ,二极管阵列检测器于检测波长 2 60nm测定。硫酸双肼酞嗪、氢氯噻嗪和氨苯喋啶的线性范围分别为 0 .0 8~ 1 .1mg/mL ,0 .0 1~ 0 .30mg/mL ,0 0 3~ 0 .45mg/mL ,检测限分别为 0 0 0 6mg/mL ,0 0 0 1mg/mL ,0 0 0 1mg/mL ,已用于北京降压0号样品的测定 相似文献
6.
I. G. Zenkevich S. V. Gushchina 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(9):1641-1646
It is shown through reversed phase high performance liquid chromatography that a characteristic feature of such abundant natural
flavonoids as flavon-3-ols is an anomalously strong antibate dependence of their retention indices (RI) on the organic solvent concentration (C) in the eluent, dRI/dC < 0. In order to interpret this anomaly, the specific optical rotation values [α]D20 of natural (+)-(2R,3R)-dihydroquercetin in different solvents are compared, confirming the reverse formation of hydrated flavonoids in aqueous
solutions. 相似文献
7.
K. Jinno 《Journal of separation science》1982,5(7):364-367
The chromatographic performance of the deuterated solvents, CD3OD and D2O, has been investigated in reversed-phase micro high performance liquid chromatography. The chromatographic performance of CD3OD is only slightly superior to that of CH3OH. However, the performance of D2 is significantly superior to that of H2O, separation of aromatics being improved by about 30%. D2 is a particularly powerful solvent for the separation iof deuterated and non-deuterated compounds. 相似文献
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K Li 《Biomedical chromatography : BMC》1990,4(5):189-192
An ion-pair reversed phase high performance liquid chromatographic method was developed for the quantitative determination of lipoperoxide (as malondialdehyde, MDA) in animal tissue using a ODS column and a mobile phase of methanol + phosphate buffer (53:47 v/v, pH 6.5). Tetrabutylammonium bromide was used as an ion-pair reagent and the detection wavelength was set at 532 nm. The method was sensitive, accurate and simple. A linear relationship was obtained between the peak height and the amount of MDA from 50 nmol/L to 1200 nmol/L and the lower limit of detection of MDA was 15 nmol/L (signal-to-noise ratio greater than 2), and the coefficient of variation at the 200 nmol/L level was 3.7% (n = 7). The results correlated well with those from the 2-thiobarbituric acid colorimetric method. The method has been used in the pathogenic studies of cerebral ischemia and acute renal failure for the determination of trace lipoperoxide. 相似文献
10.
S. S. Yang 《Chromatographia》1992,33(7-8):309-312
Summary A rapid sample preparation procedure combined with a short reversed-phase HPLC separation for the quantitation of methoprene residue in tobacco samples is described. A ground tobacco sample of 0.5 g is mixed with 3 mL of 2-propanol. The mixture is extracted for twelve minutes with the aid of sonication at an elevated temperature (45–55°C) and then filtered through a 0.45 m disposable filter prior to injection on HPLC. No sample cleanup or solvent evaporation step is required. Chromatographic analysis is performed on a C-18 column and the analysis time is 12.5 minutes. The detection limit for methoprene in tobacco samples is one part per million (g/g). 相似文献
11.
A simple and rapid method for in situ preconcentration of inorganic and organic mercury compounds in water samples, based on solid phase extraction using dithizone immobilised on a reversed-phase C18 cartridge, has been developed. The adsorbed complexes were stable on the cartridge for at least 2 weeks. The speciation analysis of methylmercury (MeHg), phenylmercury (PhHg) and inorganic mercury (Hg (II)) were done by reversed-phase high performance liquid chromatography. The calibration graphs of MeHg, PhHg and Hg (II) were linear (r>0.999) from the detection limits (0.58, 0.66 and 0.54 ng) to 38, 25 and 26 ng of Hg, respectively. The average recoveries of MeHg, PhHg and Hg (II) from spiked samples (0.3-48.0 mug l(-1) Hg) were 98+/-3, 99+/-1 and 100+/-7%, respectively. By applying SPE procedure a 200-fold concentration of the sample was obtained. 相似文献
12.
反相高效液相色谱法同时检测食物中毒样品中的敌鼠钠盐、杀鼠醚和杀鼠灵 总被引:1,自引:0,他引:1
建立了反相高效液相色谱-二极管阵列检测器同时快速检测食物中毒样品中的敌鼠钠盐、杀鼠醚和杀鼠灵的分析方法。固体样品用乙腈提取,液体样品用乙酸乙酯提取。以V(乙腈)∶V(0.010 mol/L乙酸铵)=57∶43(pH 4.50)为流动相,经C18色谱柱分离,二极管阵列检测器分别在波长286和306 nm处同时检测,在8 min内即可完成色谱分析。敌鼠钠盐、杀鼠醚和杀鼠灵在0.05~20.0μg/mL范围内与其色谱峰面积呈良好的线性关系,方法的检出限固体样品为0.015μg/g,液体样品为0.003μg/mL,样品加标平均回收率在85.0%~109.2%之间,相对标准偏差为1.0%~9.6%。 相似文献
13.
A pre-peak was separated from the main peak of a monoclonal antibody by size exclusion HPLC (SE-HPLC) analysis using two TSK-Gel G3000SWXL columns connected in series. When compared with molecular weight markers, the product peak elutes as a molecule with apparent molecular weight of 44 kDa, indicating that separation is not strictly on the basis of size exclusion and that longer retention of the antibody by this column probably results from interaction between the stationary phase and the protein molecules during separation. The pre-peak has been characterized as due to the oxidation of one of tryptophan residues on the heavy chains of this monoclonal antibody. Because the SE-HPLC method using tandem TSK-Gel G3000SWXL columns showed unsatisfactory reproducibility amongst column lots, a more reliable and accurate reversed phase HPLC (RP-HPLC) method was developed to detect the tryptophan oxidation on the heavy chains of the monoclonal antibody. The level of tryptophan oxidation determined by the reversed phase method was correlated with the amount of tryptophan oxidation observed as a pre-peak by SE-HPLC. The RP-HPLC method was qualified for precision, accuracy, linearity of the main peak and the minor peak (oxidized isoforms of the heavy chain), detection limit and quantitation limit. 相似文献
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Summary The concurrent administration of several antiepileptic drugs for the treatment of seizure disorders has become common practice. Lamotrigine is a new antiepileptic given in combination with other antiepileptic drugs, but which is not routinely measured in clinical laboratories. An isocratic high-performance liquid chromatographic method is described for the simultaneous measuring lamotrigine, carbamazepine, phenobarbital and phenytoin within 10 minutes. The chromatographic system used an Hichrom Spherisorb CN column (20 cm×4 mm, i.d., 5 m particle size), a Bondapak CN precolumn, and a mobile phase consisting of methanol : acetonitrile : 5 mM sodium acetate (5:20:75: by volume, pH adjusted to 6.3 with acetic acid). BWA 725C was used as internal standard. The drugs were extracted from 200 l of plasma with ethyl acetate, acetonitrile and 5 mM sodium acetate. After evaporation of the organic layer and reconstitution in mobile phase, 25 l of extract was eluted with mobile phase at a flow rate of 1.2 ml/min. The eluted drugs were detected by their absorption at 205 nm and quantified from their peak heights. The method was found to be rapid, relatively simple to perform and sufficiently sensitive to determine each drug over its entire therapeutic range. Lower limits of detection varied from 50–100 ng/ml, absolute recoveries from 93–98%, and mean intra- and inter-assay CVs were <3.0%. 相似文献
15.
We have compared anion exchange chromatography on APS-Hypersil (4.6 x 100 mm) eluted with a phosphate gradient with reversed phase chromatography on ODS-Hypersil (4.6 x 100 mm) in the presence of either tetrabutylammonium (TBA) or triethylammonium (TEA) ions with a methanol gradient. The systems have been compared both for ease of operation and for their resolving power with standard mixtures and acid extracts of both normal red cells (RBC) and ischaemic tissues. The two chromatographic modes exhibited similar separating efficiencies for standard mixtures of nucleotides but retention times were most stable using reversed phase liquid chromatography (RPLC) with TEA. Anion exchange columns slowly lost ion exchange capacity but selectivity was unchanged. RPLC in the presence of TBA gave reproducibile capacity factors only when operated isocratically due to irreversible changes to the silica surface. For RBCs the RPLC with TEA and anion exchange systems resolved 17 and 15 peaks, respectively, and for the ischaemic samples 22 and 14 peaks, respectively. However, nucleosides and bases were also resolved by the ODS column causing chromatographic crowding and uncertain peak identification. 相似文献
16.
次级化学平衡反相高效液相色谱法分离银杏酚酸 总被引:4,自引:0,他引:4
采用LC/(-)ESI-MS法对银杏叶中的致敏性成分银杏酚酸进行了鉴定。利用次级化学平衡理论,建立了银杏酚酸的反相银化高效液相色谱分离方法。从色谱热力学角度对银离子分离银杏酚酸的影响进行了考察。在流动相中添加银离子,降低了具不饱和侧链银杏酚酸的保留时间,且银离子浓度与容量因子的对数之间存在良好线性关系。在确定的色谱条件下,四种银杏酚酸均获得较高的分离度,表明反相银化液相色谱是分离碳数与饱和度不相同的银杏酚酸同系物的有效方法。 相似文献
17.
The low temperature effect has been investigated in reversed phase micro high performance liquid chromatography with various aqueous mobile phase systems by an approach based on enthalpy-entropy compensation. The compensation temperatures, Tc , were determined for these systems, and the results show that the retention mechanism in a lower temperature column is similar to that in a normal temperature column in the reversed phase mode at mobile phase water contents above 9.8%. At lower water contents, the separation mechanism is different from that in the reversed phase mode, but otherwise very similar to that in the normal phase mode. 相似文献
18.
Simultaneous separation of nonionic surfactants and polyethylene glycols by reversed phase high performance liquid chromatography 总被引:2,自引:0,他引:2
Summary The simultaneous separation of polyethylene glycol and its derivatives such as the lauryl alcohol and lauric acid ethoxylate
oligomers was carried out by reversed phase high performance liquid chromatography. Branched fluorinated silica gel columns
combined with evaporative light scattering detection were used for the characterization of nonionic surfactants. Lauryl alcohol
ethoxylate oligomers were separated at 10°C with an isocratic eluent according to ethoxylate number and the retention time
of the oligomers decreases with increasing ethoxylate number. The Van’t Hoff plots of retention factor of lauryl alcohol ethoxylate
gave a complex cure, which is anomalous behavior for reversed phase high performance liquid chromatography. The anomalous
Van’t Hoff plots were explained by a partial conformational change from polar to less polar conformers with increasing temperature.
The most significant features for the analysis of the lauryl alcohol ethoxylate were the use of acetonitrile as mobile phase
and operating temperature. The polyethylene glycol was separated according to ethoxylate number and the retention time of
oligomers increased with increasing ethoxylate number. The Van’t Hoff plots of retention factor of polyethylene glycol had
negative slopes. It was presumed that the polar conformation of the ethylene oxide chain decreased with increasing temperature.
The lauryl alcohol ethoxylate and polyethylene glycol were separated simultaneously in gradient elution as a result of the
conformational change of the ethylene oxide chain. As a practical example, lauric acid ethoxylate simultaneously separated
into free polyethylene glycol, ethoxylate monolaurate and ethoxylate dilaurate in gradient elution. 相似文献
19.
Determination of catechol-O-methyltransferase activity in erythrocytes by high performance liquid chromatography with electrochemical detection 总被引:1,自引:0,他引:1
A rapid assay employing HPLC with electrochemical detection for catechol-O-methyltransferase (COMT) activity in red blood cells is described. Enzyme activity is determined from erythrocyte lysates using S-adenosyl-L-methionine as methyl donor and 3,4-dihydroxybenzoic acid as substrate. The 3-O- and 4-O-methylated reaction products are measured by high-performance liquid chromatography with electrochemical detection. Human erythrocyte soluble form of COMT had Km values of 6.1 microM and 26.0 microM for S-adenosyl-L-methionine and dihydroxybenzoic acid, respectively. The mean O-methylation ratio for the soluble form of COMT was 5.3. An O-methylation ratio of 15.5 was estimated in the membrane fraction of an erythrocyte pool from three samples. The activities of soluble COMT in erythrocytes of some animal species are also reported. The procedure is easily automated, and a large number of samples can be processed during one working day. 相似文献
20.
A new method was developed for the analysis of illicit drugs in human urine by coupling carrier-mediated liquid phase microextraction (LPME) to high performance liquid chromatography (HPLC). By adding an appropriate carrier in organic phase, simultaneous extraction and enrichment of hydrophilic (morphine and ephedrine) and hydrophobic (pethidine) drugs were achieved. Effects of the types of organic solvents and carriers, the carrier concentration in the organic phase, the HCl concentration in the acceptor solution, the stirring rate, and the extraction time on the enrichment factor of analytes were investigated. Under the optimal experimental conditions, high enrichment factors (202-515) were obtained. The linear detection ranges were 0.1-10 mg L−1 for the studied drugs. The limits of detection (LOD) at signal-to-noise ratio of 3 were 0.05 mg L−1 for both morphine and ephedrine, and 0.02 mg L−1 for pethidine. This method was successfully applied to analysis of ephedrine in real urine specimens, revealing that the determination of illicit drugs in urine was feasible. 相似文献