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1.
High performance liquid chromatography coupled with resonance light scattering detection was developed for separation and determination of heparin in plasma. A good chromatographic separation was achieved using an aminex HPX-87H column (300 mm × 7.8 mm, 9 μm) and a mobile phase of 5.0 mmol L?1 H2SO4 at the flow rate of 0.5 mL min?1. The enhanced resonance light scattering signals were derived from a large aggregate formation between heparin and cetyltrimethylammonium bromide used as the molecular recognition probe. The parameters of the post-column reaction (pH, concentration and flow rate of the reagent, length of the reaction coil, and temperature) were optimized. The limit of detection for heparin in plasma was 0.2 mg L?1. The method has been applied to the determination of heparin in dialysis patient plasmas.  相似文献   

2.
Xiong  Xunyu  Zhang  Qunzheng  Xiong  Fengmei  Tang  Yuhai 《Chromatographia》2008,67(11):929-934

A simple and sensitive method was developed for the determination of three nonsteroidal anti-inflammatory drugs (NSAIDs)—ibuprofen, naproxen and fenbufen in human plasma. The method involved in column liquid chromatographic separation and chemilumenescence (CL) detection based on the CL reaction of NSAIDs, potassium permanganate (KMnO4) and sodium sulfite (Na2SO3) in sulfuric acid (H2SO4) medium. The chromatographic separation was carried out using a reversed-phase C18 column, which allowed the selective determination of the three medicines in the complicated samples. The special features of the CL detector provided lower LOD for determination than that of existing chromatographic alternatives. The results indicated that the linear ranges were 0.01–10.0 μg mL−1 for ibuprofen, 0.001–1.0 μg mL−1 for naproxen, and 0.01–10.0 μg mL−1 for fenbufen. The limits of detection were 0.5 ng mL−1 for ibuprofen, 0.05 ng mL−1 for naproxen and 0.5 ng mL−1 for fenbufen (S/N = 3). All average recoveries were in the range of 90.0–102.3%. Finally, the method had been satisfactorily applied for the determination of ibuprofen, naproxen and fenbufen in human plasma samples.

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3.
Bai  Xin-Wei  Song  Cui-Hua  You  Jin-Mao  Sun  Zhi-Wei  Fu  Yan-Yan  Li  Guo-Liang 《Chromatographia》2010,71(11):1125-1129

A simple and mild method for the determination of fatty acids (C1 – C10) based on a condensation reaction using 7-aminonaphthalene-1,3-disulfonic acid (ANDSA) as labeling reagent with capillary zone electrophoresis has been developed. The detection was performed with a diode array detector at 254 nm. A 58.5 cm × 50 μm i.d. (50 cm effective length) untreated fused-silica capillary was used. To optimize the separation conditions, the background electrolyte concentration, column temperature, voltage and other factors were evaluated. The optimal separation conditions were as follows: 30 mmol L−1 borate buffer (pH 9.5), 15 mmol L−1 β-CD, temperature at 20 °C, pressure 50 mbar and injection time 8 s. Under the established conditions, 10 fatty acid derivatives could be well-separated within 17 min. The linearity was in the range of 0.07–5.0 μmol L−1. Detection limits (at a signal-to-noise ratio of 3) were in the range of 0.027–0.042 μmol L−1. The fatty acids from the extracted Funaria Hedw. and Selaginella samples were determined with satisfactory results.

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4.
Li  Siwen  Yu  Hong  Ma  Yajie 《Chromatographia》2011,74(11):759-765

A method of ion-pair chromatography was developed on a reversed-phase silica-based monolithic column for the fast and simultaneous determination of trifluoromethanesulfonate (CF3SO3 ) and p-toluenesulfonate (C7H7SO3 ). The analysis was performed using a mobile phase of tetrabutylammonium hydroxide + citric acid + acetonitrile on the Chromolith Speed ROD RP-18e column with direct conductivity detection. The effects of the eluent, column temperature and flow rate on the retention of the anions were investigated. The experimental phenomenon was discussed according to hydrophobic interaction and ion-exchange mechanism in the separation. The optimized chromatographic conditions were selected. The optimized eluent for the separation consisted of 0.2 mmol L−1 tetrabutylammonium hydroxide + 0.10 mmol L−1 citric acid + 9% acetonitrile (pH 5.5). The flow rate was set at 6.0 mL min−1. The column temperature was 25 °C. Under the optimal conditions, the better separation of CF3SO3 and C7H7SO3 was achieved without any interference by other anions (Cl, Br, I, NO3 , SO4 2−, ClO3 , BF4 and PF6 ). The detection limit (S/N = 3) was 0.28 and 0.71 mg L−1 for CF3SO3 and C7H7SO3 , respectively. The method has been applied to the determination of CF3SO3 and C7H7SO3 in ionic liquids. The spiked recoveries of CF3SO3 and C7H7SO3 were 101.1 and 100.2%, respectively.

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5.
Cai  Meiqiang  Shen  Chenyi  Jin  Micong 《Chromatographia》2013,76(15):985-991

Wilforidine is a potentially efficient medicine to cure autoimmune diseases. In this paper, a sensitive and selective liquid chromatographic method coupled with atmospheric -pressure chemical ionization mass spectrometry (LC–APCI–MS/MS) has been developed for quantification of wilforidine in human plasma. Samples were deproteinized with acetonitrile and cleaned by solid-phase extraction. The chromatographic separation was performed on an analytical RRHD C18 column (50 × 2.1 mm) using ammonium acetate solution (10.0 mmol L−1)/acetonitrile (30/70, v/v) as the mobile phase at a flow rate of 0.7 mL min−1. Detection was carried out by the positive multiple reaction monitoring mode with transitions of m/z 780 → 684 for wilforidine, and 646 → 586 for aconitine (internal standard), respectively. The calibration curve was linear (r = 0.9991) in the concentration range of 0.5–100.0 μg L−1 with a lower limit of quantification of 0.5 μg L−1 in plasma. Intra- and inter-day relative standard deviations were less than 6.8 and 13.1 %, respectively, and the recoveries were between 88.0 and 96.0 %. This accurate and highly specific assay provides a useful method for evaluating the pharmacokinetics of wilforidine in human plasma.

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6.
Deng  Weijie  Zhang  Xiangnian  Sun  Zhiping  Yin  Jilin  Zhou  Zheng  Han  Liping  Zhao  Shujin 《Chromatographia》2012,75(11):629-633

A new and simple high-performance liquid chromatography with evaporative light scattering detector method for the determination of Kryptofix 2.2.2 (K-222) in the radiopharmaceuticals of 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) and 3′-deoxy-3′-[18F]fluorothymidine ([18F]FLT) was developed. A C18 column was used and the mobile phase was 10 % (v/v) methanol and 90 % (v/v) water (0.1 % trifluoroacetic acid, v/v) at a flow rate of 0.2 mL min−1. The drift tube temperature was 40 °C. The pressure of nebulizing gas (N2) was 3.0 bar. The gain was 10. Good separation of K-222 from main related substances could be achieved. Excellent linearity (r 2 = 0.9995) was obtained over the range of 5–100 μg mL−1. The precision ranged from 0.68 to 5.16 % (RSD) and the accuracy ranged from −3.05 to 2.62 % (RE). The limit of detection was 2 μg mL−1. This method offers simple, rapid and quantitative detection of K-222, thus making it acceptable for routine determination.

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7.

A method for isotachophoretic determination of potassium and ammonium cations in fertilizers and silage was developed. A capillary of 0.4 mm i.d. and 100 mm effective length made of fluorinated ethylene–propylene copolymer was filled with an electrolyte system consisting of 10 mmol L−1 RbOH + 0.1% (w/v) hydroxyethylcellulose, adjusted to pH 9.0 with l-histidine (leading electrolyte) and 10 mmol L−1 lithium citrate (terminating electrolyte). Using contactless conductivity detection, the calibration curves in the tested concentration range up to 0.5 mmol L−1 were linear for both cations. The concentration detection limits for potassium and ammonium were 2.9 and 2.7 μmol L−1, respectively. RSD values of step lengths (n = 6) were 1.3% for potassium and 1.5% for ammonium. The separation time was about 20 min. Similar results were obtained with cesium cation used as the leading ion, however, in the system with rubidium better resolution of other cations present in tested matrices was reached. The elaborated method is simple to perform, sufficiently sensitive and accurate and can be recommended as an alternative procedure to the methods used so far for the determination of potassium and ammonium.

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8.
Li  Fajie  Zhang  Haiying  Li  Yan  Yu  Yingjia  Chen  Yile  Xie  Meifen  Duan  Gengli 《Chromatographia》2012,75(3-4):187-191

A rapid and accurate size exclusion chromatography method for the simultaneous identification and quantification of dextran 20 and sucrose with optical activity in the lyophilized thrombin powder was developed and validated. The assay was conducted on a Hitachi model D-2000 Elite HPLC system with a TOSOH TSKgel G3000 PWxl column (30 cm × 7.8 mm, 7 μm particle size) and an Alltech 3300 evaporative light scattering detector (ELSD). The mobile phase was acetonitrile–water (46:54, v/v) mixture delivered at a flow rate of 0.7 mL min−1 at 25 °C. The ELSD was operated at a nebulizer-gas flow rate of 2.0 L min−1 and drift tube temperature of 90 °C, and the gain was set at one. Afterward, method validation system for the size exclusion chromatography analysis was developed. The linear range was 0.1–1.6 and 0.1–1.0 g L−1 for dextran 20 and sucrose, respectively, and the detection limits were <0.02 g L−1 for dextran 20 and <0.015 g L−1 for sucrose. Inter-day and intra-day variabilities showed that RSD ranged from 0.27 to 4.20%. Recovery validation showed that average recovery was between 96.00 and 103.98%. The developed analytical procedure was successfully applied to determine the contents of dextran 20 and sucrose in the lyophilized thrombin powder.

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9.
Ate&#;  Z.  &#;zden  T.  &#;zilhan  S.  Toptan  S. 《Chromatographia》2007,66(1):123-127

A simple method for the determination of carbamazepine and its active metabolite carbamazepine-10,11-epoxide by ultra performance liquid chromatography (UPLC) with ultraviolet absorbance detection (TUV) was developed. The method involves a two-step protein precipitation by liquid–liquid extraction. Phenytoin sodium was used as the internal standard. The separation was carried out on Acquity C18 column with acetonitrile:methanol:KH2PO4 buffer (adjusting pH to 4.6 with 85% o-phosphoric acid) (180/180/170, v/v/v) as the mobile phase at a flow rate of 0.4 mL min−1. Linear detection response was obtained for concentrations ranging from 50 to 5,000 ng mL−1. The limit of quantification (LOQ) was 50 ng mL−1. The method was validated successfully for the determination of carbamazepine and its active metabolite carbamazepine-10,11-epoxide, which can be applied through pharmacokinetics and bioequivalence studies.

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10.
Tzanis  Lydie  Simon  Patrice  Walcarius  Alain 《Chromatographia》2008,67(11):857-861

A simple liquid chromatographic method was developed for the separation and simultaneous determination of cobalt and nickel as chelates with 1-(2-pyridylazo)-2-naphthol (PAN). The method, using a switching column technique for the on-line purification and separation, enables to reach the sub-microgram per litre concentration level excluding off-line sample treatment with the exception of the derivatization reaction. Two small-sized columns packed with CN- and C4-bonded stationary phases were selected and used considering their complementary behaviour with respect to chelated Co and Ni ions. The analysis was performed within 10 min using an optimised eluent (water–acetonitrile–methanol–tetrahydrofuran, 40:45:10:5, v/v/v/v) containing Tween 40 (10−3 M) and acetate buffer (5 × 10−3 M, pH 4.8). Detection was performed by UV-vis spectrophotometry (λ = 565 nm) permitting to reach quantification limits of 0.9 and 0.5 μg L−1 for Co and Ni, respectively.

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11.
Ma  Yanmei  Cheng  Shan  Leski  Michael L.  Luo  Dali  He  Junqi 《Chromatographia》2008,68(11):1027-1032

A rapid and sensitive method for the quantitative determination of picroside II in rat plasma was developed and validated using liquid chromatographic separation with tandem mass spectrometric detection. The analytes of interest were extracted from rat plasma samples by ethyl acetate after acidification with 1.0% acetic acid solution. Chromatographic separation was achieved on a Hypersil GOLD column (50 × 2.1 mm I.D., 5 μm) using a mobile phase consisting of acetonitrile–0.1% formic acid solution (30:70, v/v) at a flow rate of 0.2 mL min−1. Detection was performed on a triple quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) mode via electrospray ionization (ESI). The calibration curve was linear in the concentration range of 1.00–400 ng mL−1 in rat plasma, with a 1.00 ng mL−1 lower limit of quantification (LLOQ). Satisfactory results were achieved for intraday repeatability [relative standard deviation (RSD) = 6.4–12.4%] and inter-day precision (RSD = 6.8–14.7%). The accuracy in terms of relative error ranged from −2.1 to 10.0%. The extraction recoveries of picroside II and icariin (internal standard) were 80.0 and 89.3%, respectively. The developed method was successfully employed to determine picroside II plasma concentrations after oral administration to Wistar rats.

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12.
Dogan-Topal  B.  Ozkan  S. A.  Uslu  B. 《Chromatographia》2007,66(1):25-30

A rapid, sensitive, and specific reverse phase high performance liquid chromatography with diode array detection procedure for the simultaneous determination of abacavir, efavirenz and valganciclovir in spiked human serum is described. Separation was performed on a 5 μm Waters Spherisorb column (250 × 4.6 mm ID) with acetonitrile: methanol:KH2PO4 (at pH 5.00) (40:20:40 v/v/v) isocratic elution at a flow rate of 1.0 mL min−1. Calibration curves were constructed in the range of 50–30,000 ng mL−1 for abacavir and efavirenz, and 10–30,000 ngmL−1 for valganciclovir in serum samples. The limit of detection and limit of quantification concentrations of the HPLC method were 3.80 and 12.68 ng mL−1 for abacavir, 2.61 and 8.69 ng mL−1 for efavirenz, 1.30 and 4.32 ng mL−1 for valganciclovir. The method has been applied, without any interference from excipients or endogenous substances, for the simultaneous determination of these three compounds in human serum.

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13.

This work describes the voltammetric and amperometric behavior of a high number of PASHs (sulfides, thiophenes, benzothiophenes, dibenzothiophenes, indenothiophenes, naphtothiophenes, thienothiophenes, phenanthrothiophenes, and acenaphtothiophenes) at gold disc electrodes aiming at their identification and determination in petroleum asphalts. The adsorption/redox processes expected for sulfur compounds at gold electrodes could be observed in all the studied PASHs in DMSO and hydromethanolic medium. Differential pulse (DP) voltammetry in non-aqueous solutions (0.1 mol L−1 NaClO4 in DMSO) was approached for determining non-volatile PASHs in asphalts submitted to different aging processes. It was found herein that the DP voltammetric monitoring of PASH oxidation at + 0.7 V (vs. Ag/AgCl/LiCl 3 mol L−1) for virgin/aged asphalts can be used for the comparative study of asphalts based on the consumption of PASHs. Additionally, pulsed amperometric detection (PAD) in hydroalcoholic solution (10 mmol L−1 acetate buffer in 65% methanol) coupled with a chromatographic separation was approached for determining volatile PASHs in asphalts submitted to thermal decomposition processes. A detection cycle of 2 s involving oxidative (0.4 s at + 0.4 V) and reductive (1.2 s at − 1.0 V) cleaning pulses after a detection pulse of − 0.8 V (0.4 s) applied successively to the gold electrode (vs. Pd/PdO) was found to be optimal for regenerating the gold surface during successive chromatographic runs of PASHs. Thus, reversed-phase liquid chromatography (LC)–coupled PAD was found useful to separate a complex mixture of PASHs. The optimized PAD and LC separation was further applied to investigate the presence of electroactive PASHs as volatile compounds in asphalt fumes generated at 260 °C.

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14.
Longhua  Xu  Limin  Zhang  Xuguang  Qiao  Zhixiang  Xu  Jiaming  Song 《Chromatographia》2012,75(5-6):269-274

How to determine the quantities of acrylamide produced in foods is an important problem. Here, we report a sensitive method of high performance liquid chromatography based on a solid phase extraction using a reversed phase C18 column, which was characterized by adsorption experiments with good adsorption ability and rapid adsorption dynamic toward acrylamide. Under optimal condition, the detection limit based on three times the signal-to-noise ratio of the baseline near the analyte peak was 66.0 ng L−1. With a loading flow rate of 2.0 mL min−1 for loading 100 mL, an enrichment factor of 182 was obtained. The RSD for five replicate extractions of 50 μg L−1 acrylamide was 4.1%. Blank potato samples spiked with acrylamide at 0.125, 0.250, and 0.375 μg g−1 levels were analyzed with recoveries ranging from 88.9 to 89.5%. Moreover, this method was applied to quantitative detection of acrylamide in the crust and potato chip samples.

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15.

Taurine is an amino acid which is not incorporated into proteins but found in the cytosol of many mammalian cells, in high concentrations (2–30 mM). Increase in plasma taurine concentration has already been reported after surgical trauma, X-radiation, muscle necrosis, carbon tetrachloride-induced liver damage, and paracetamol overdose. Plasma taurine concentration was measured using LC with fluorescence detection following derivatization by o-phtalaldehyde plus 3-mercapto-propionic acid and α-aminobutyric acid as internal standard. Under these conditions the retention time of taurine was 10 min. This method was sensitive enough, to quantify 150 pg mL−1 and detect 50 pg mL−1 of taurine ranging normally between 65 and 179 mmol L−1 (8–22 μg mL−1). The validated method allowed simple determination of human plasma taurine in pharmacokinetic and biomarker studies.

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16.
Maher  Hadir M.  Youssef  Rasha M. 《Chromatographia》2009,69(3-4):345-350

Two chromatographic methods have been described for the simultaneous determination of metronidazole (MET) and spiramycin (SPY) in their mixtures. The first method was based on a high performance thin layer chromatographic (HPTLC) separation of the two drugs followed by densitometric measurements of their spots at 240 nm. The separation was carried out on Merck TLC aluminum sheets of silica gel 60 F254 using methanol: chloroform (9:1, v/v) as a mobile phase. Analysis data was used for the linear regression line in the range of 1.0–2.0 and 0.8–2.0 μg band−1 for MET and SPY, respectively. The second method was based on a reversed-phase liquid chromatographic separation of the cited drugs on a C-18 column (5 μm, 250 × 4.6 mm, i.d.). The mobile phase consisted of a mixture of phosphate buffer of pH 2.4 and acetonitrile (70:30, v/v). The separation was carried out at ambient temperature with a flow rate of 1.0 mL min−1. Quantitation was achieved with UV detection at 232 nm based on peak area with linear calibration curves at concentration ranges 0.4–50.0 and 0.5–50.0 μg mL−1 for MET and SPY, respectively. The proposed chromatographic methods were successfully applied to the determination of the investigated drugs in pharmaceutical preparations. Both methods were validated in compliance with ICH guidelines; in terms of linearity, accuracy, precision, robustness, limits of detection and quantitation and other aspects of analytical validation.

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17.
Shi  Ming  Huang  Yong  Li  Xiangtang  Zhao  Shulin 《Chromatographia》2009,70(11):1651-1657

A microchip electrophoresis method with laser induced fluorescence detection was developed for the detection of agmatine (Agm) and octopamine (Oct). The fluorescent derivatization reagent, fluorescein isothiocyanate was used for precolumn derivatization of Agm and Oct. The sodium dodecyl sulfate (SDS) micelles was employed as pseudostationary phase for the separation of Agm and Oct with other endogenous compounds exist in biological samples. Some parameters including buffer concentration, buffer pH, SDS concentration and separation voltage were investigated in detail. Under the optimum conditions, the separation and determination of Agm and Oct was performed within 40 s. The calibration curves were linear for both Agm and Oct over the concentration range of 1.0 × 10−7 to 4.0 × 10−5 M and 1.5 × 10−7 to 4.5 × 10−5 M, respectively. The detection limits of Agm and Oct (S/N = 3) are 5.0 × 10−8 and 8.0 × 10−8 M, respectively. These values make the method very suitable for the determination of Agm and Oct in rat brain tissue and human plasma as demonstrated in this paper.

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18.
《Analytical letters》2012,45(16):2593-2605
A method was developed for the determination of vitamin B12 based on the enhancement of cobalt (II) on the chemiluminescence (CL) reaction between luminol and percarbonate (powerful source of hydrogen peroxide). The release of cobalt (II) from the vitamin B12 was reached by a simple and fast microwave digestion (20 s microwave digestion time and a mix of nitric acid and hydrogen peroxide). A charge coupled device (CCD) photodetector, directly connected to the cell, coupled with a simple continuous flow system was used to obtain the full spectral characteristics of cobalt (II) catalyzed luminol-percarbonate reaction.

The optima experimental conditions were established: 8.0 m mol L?1 luminol in a 0.075 mol L?1 carbonate buffer (pH 10.0) and 0.15 mol L?1 sodium percarbonate, in addition to others experimental parameters as 0.33 mL s?1 flow rate and 2 s integration time, were the experimental conditions which proportionate the optimum CL emission intensity. The emission data were best fitted with a second-order calibration graph over the cobalt (II) concentration range from 4.00 to 300 µ g L?1 (r2 = 0.9990), with a detection limit of 0.42 µ g L?1. The proposed method was successfully applied to the determination of vitamin B12 in pharmaceuticals.  相似文献   

19.
Zou  Jian-Jun  Fan  Hong-Wei  Guo  Da-Qing  Li  Ying-Bin  Lin  Song  Zhu  Yu-Bing  Yu  Cui-Xia  Zhou  Jie  Liu  Jiang-Hui  Hu  Yun-Fang 《Chromatographia》2009,70(11):1581-1586

A sensitive and specific liquid chromatography-tandem-mass spectrometry method was developed and validated for the simultaneous determination of clopidogrel and its carboxylic acid metabolite (SR26334) in human plasma using nateglinide and pioglitazone as internal standards. Analytes were extracted from 0.50 mL of plasma using diethyl ether–n-hexane (4:1, v/v). Chromatographic separation was performed on a Teknokroma C18 column with a mobile phase of methanol–water (containing 0.1% formic acid) (80:20, v/v) at a flow rate of 0.20 mL min−1 within 5.6 min. Linearity was established over the concentration range of 0.005–5 ng mL−1 for clopidogrel and 20–2,500 ng mL−1 for SR26334. Intra- and inter-batch standard deviations were less than 9.2% and the accuracy of this assay was found to fall within an acceptable range ≤10.0%. The method was successfully applied to the therapeutic drug monitoring of clopidogrel.

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20.
Ning  Shujing  You  Jinmao  Sun  Zhiwei  Zhang  Shijuan  Ji  Zhongyin 《Chromatographia》2012,75(19):1107-1116

A simple and sensitive method for the determination of free aliphatic amines using 10-phenyl-acridone-2-sulfonyl chloride (PASC) as a labeling reagent by high-performance liquid chromatography with fluorescence detection and online mass spectrometry identification (HPLC-FLD-MS) has been developed. Derivatization conditions including reagent concentration, buffer pH, reaction time and temperature were optimized. PASC reacted with aliphatic amines at 50 °C for 4 min in aqueous acetonitrile (ACN) in the presence of sodiumtetraborate–NaOH buffer (0.10 mol L−1, pH 9.0) to give high yields of PASC-amine derivatives. Derivatives exhibited intense fluorescence with an excitation maximum at λex 265 nm and an emission maximum at λem 418 nm. The separation of derivatives was performed by a reversed-phase Hypersil BDS C8 column in combination with a gradient elution. The identification of derivatives was carried out by online post-column mass spectrometry with atmospheric pressure chemical ionization (APCI) source in positive-ion detection mode. Excellent linear responses were observed with the correlation coefficients of larger than 0.9997, and detection limits (at a signal-to-noise of 3:1) were from 3.0 to 24.3 fmol. Comparing with 10-ethyl-acridine-2-sulfonyl chloride (EASC), PASC exhibited more intense fluorescence and ultraviolet absorbance. The proposed method is sensitive and reproducible for the determination of aliphatic amines from water and soil samples.

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