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1.
A rapid, accurate and sensitive method has been developed for the quantitative determination of four fluoroquinolone antimicrobial agents, enoxacin, norfloxacin, ofloxacin and ciprofloxacin, with high in-vitro activity against a wide range of Gram-negative and Gram-positive organisms.A Kromasil 100 C(8) 250 mm x 4 mm, 5 microm analytical column was used with an eluting system consisting of a mixture of CH(3)CN-CH(3)OH-citric acid 0.4 mol L(-1) (7:15:78 %, v/v). Detection was performed with a variable wavelength UV-visible detector at 275 nm resulting in limits of detection: 0.02 ng per 20 microL injection for enoxacin and 0.01 ng for ofloxacin, norfloxacin and ciprofloxacin. Hydrochlorothiazide (HCT) was used as internal standard at a concentration of 2 ng microL(-1). A rectilinear relationship was observed up to 2 ng microL(-1) for enoxacin, 12 ng microL(-1) for ofloxacin, 3 ng microL(-1) for norfloxacin, and 5 ng microL(-1) for ciprofloxacin. Separation was achieved within 10 min. The statistical evaluation of the method was examined by performing intra-day (n=8) and inter-day precision assays (n=8) and was found to be satisfactory with high accuracy and precision. The method was applied to the direct determination of the four fluoroquinolones in human blood serum. Sample pretreatment involved only protein precipitation with acetonitrile. Recovery of analytes in spiked samples was 97+/-6% over the range 0.1-0.5 ng microL(-1).  相似文献   

2.
A densitometric high performance thin-layer chromatography (HPTLC) method was developed and validated for the quantitative analysis of haloperidol in tablets. Chromatographic separation was achieved on precoated silica gel F 254 HPTLC plates using a mixture of acetone/chloroform/n-butanol/acetic acid glacial/water (5:10:10:2.5:2.5 v/v/v/v/v) as the mobile phase. Quantitative analysis was carried out at a wavelength of 254 nm. The method was linear in the 10-100 ng/microL range, with a determination coefficient of 0.999. The coefficients of variation for precision were not higher than 2.35%. The detection limit was 0.89 ng/microL, and the quantification limit was 2.71 ng/microL. The accuracy ranged from 97.76 to 100.33%, with a CV not higher than 4.50%. This method was successfully applied to quantify haloperidol in real pharmaceutical samples, including the comparison with HPLC measurements. The method was fast, specific, with a good precision and accuracy for the quantitative determination of haloperidol in tablets.  相似文献   

3.
A densitometric high performance thin-layer chromatographic (HPTLC) method was developed and validated for quantitative analysis of L-DOPA in tablets. Chromatographic separation was achieved on precoated silica gel F 254 HPTLC plates using a mixture of acetone-chloroform-n-butanol-acetic acid glacial-water (60:40:40:40:35 v/v/v/v/v) as mobile phase. Quantitative analysis was carried out at a wavelength of 497 nm. The method was linear between 100 and 500 ng/microL, with a correlation coefficient of 0.999. The intra-assay variation was between 0.26 and 0.65% and the interassay was between 0.52 and 2.04%. The detection limit was 1.12 ng/microL, and the quantification limit was 3.29 ng/microL. The accuracy ranged from 100.40 to 101.09%, with a CV not higher than 1.40%. The method was successfully applied to quantify L-DOPA in real pharmaceutical samples, including the comparison with HPLC measurements. The method was fast, specific, with a good precision, and accurate for the quantitative determination of L-DOPA in tablets.  相似文献   

4.
A sensitive and selective liquid chromatographic (LC) assay was developed to determine the concentration of pyrimethamine in animal tissue and egg by fluorescent derivative. Animal samples were extracted with acetonitrile, centrifuged, and purified by hexane. Fluorescent derivatization was performed by reacting pyrimethamine with chloroacetaldehyde and subjected to LC with fluorescence detection (excitation wavelength 300 nm, emission wavelength 420 nm). The limit of detection was 10 ng/g (10 ppb) and the standard calibration curve was linear in the range of 1-100 ppb (0.01-1 ng/10 microL). Recoveries from samples fortified at levels of 0.1 and 1 ppm (microg/g) were 61.0-77.4 and 65.5-81.2%, respectively. The method was applied to the monitoring of marketed samples. Pyrimethamine was not determined in any of the 70 samples: 20 swine muscle; 20 chicken muscle; 10 chicken liver; and 20 egg.  相似文献   

5.
An instrumental planar chromatographic (HPTLC) method for quantitative analysis of clozapine in human serum was developed and validated. Clozapine was extracted with n-hexane-isoamyl alcohol (75:25 v/v). The chromatographic separation was achieved on precoated silica gel F 254 HPTLC plates using a mixture of chloroform and methanol (9:1 v/v) as mobile phase. Quantitative analyses were carried out by densitometry at a wavelength of 290 nm. The method was linear between 10 and 100 ng/spot, corresponding to 0.10 and 1.00 ng/microL of clozapine in human serum after extraction process and applying 10 microL to the chromatographic plates. The method correlation coefficient was 0.999. The intra-assay variation was between 2.10 and 3.33% (n = 5) and the interassay was between 2.67 and 4.44% (n = 9). The detection limit was 0.03 ng/microL, and the quantification limit was 0.05 ng/microL. The method proved to be accurate, with a recovery between 97.00 and 99.00%, with an RSD not higher than 7.22%, and was selective for the active principle tested. This method was successfully applied to quantify clozapine in patient serum samples. In conclusion, the method is useful for the quantitative determination of clozapine in serum.  相似文献   

6.
张丹  曾经泽  边巴仓决  蒋学华 《色谱》1997,15(6):515-517
采用ODS柱,甲醇-稀磷酸溶液(7624)为流动相,260nm为检测波长,建立了测定血浆中吲哚美辛浓度的高效液相色谱法,并测定了吲哚美辛控释胶囊炎痛康的血药浓度。结果表明,血浆中吲哚美辛浓度在0.125~5.0mg/L范围内线性关系良好(r=0.9996),检测限62.5μg/L(S/N=31),平均回收率为100.4%,日内和日间RSD均小于5%。11位受试者单剂量口服炎痛康后的相对生物利用度为102.38%。  相似文献   

7.
A rapid and sensitive column-switching semi-micro HPLC method is described for the direct analysis of tofisopam in human serum. The sample (100 microL) was directly injected onto the precolumn (Capcell Pak MF Ph-1), where unretained proteins were eluted to waste. Tofisopam was then eluted into an enrichment column using 13% acetonitrile in 50 mM phosphate buffer (pH 7.0) containing 5 mM sodium octanesulfonate and subsequently into the analytical column using 43% acetonitrile in 0.1% phosphoric acid containing 5 mM sodium octanesulfonate. The detection limit (2 ng/mL), good precision (CV < or = 4.2%) and speed (total analysis time 24 min) of the present method were sufficient for drug monitoring. This method was successfully applied to a bioequivalence test of two commercial tofisopam tablets.  相似文献   

8.
A sensitive high-performance liquid chromatographic method with fluorescence detection to determine 3,4-methylenedioxymethamphethamine (MDMA) and 3,4-methylenedioxyamphethamine (MDA) in human and rat whole blood or plasma samples was developed by using 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) as a label. MDMA and MDA in a small amount of blood sample (ca 100 microL) were extracted by liquid-liquid extraction with ethyl acetate, and were derivatized with DIB-Cl under mild conditions (10 min at room temperature). A good separation of DIB-derivatives could be achieved within 45 min using a commercially available ODS column with an isocratic eluent of 10 mM citric acid-20 mM Na(2)HPO(4) aqueous buffer (pH 4.0)-CH(3)CN-CH(3)OH (50:45:5, v/v/v %). The calibration curves prepared with 1-methyl-3-phenylpropylamine (MPPA) as an internal standard showed good linearity (r = 0.999) with 0.36-0.83 ng/mL detection limit at a signal-to-noise ratio of 3. MDMA and MDA in rat whole blood could be monitored for 6 h after a single administration of MDMA (2.2 mg/kg, i.p.). The pharmacokinetic parameters for MDMA and MDA obtained by triplicate measurements were 426 +/- 23 and 39 +/- 6 ng/mL (C(max)), 20 +/- 5 and 100 +/- 10 min (T(max)), respectively.  相似文献   

9.
8-Hydroxy-2'-deoxyguanosine (8OHdG), one of the major oxidative DNA lesions induced by radical agents, is commonly used as a biomarker for oxidative stress, nowadays preferably in urine. In the absence of a commercially available internal standard a micro-high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (micro-HPLC/ESI-MS/MS) method, suitable for routine analysis of 8OHdG in human urine using external calibration, was developed. Evaluation of the matrix effect showed that the method allows highly sensitive and accurate quantitation despite the absence of an internal standard. HPLC analysis was performed using gradient elution at a flow rate of 10 microL min(-1) using a capillary reversed-phase column and an injection volume of 0.5 microL, with detection of 8OHdG in positive multiple reaction monitoring (MRM) mode. The absolute limit of detection was 0.35 fmol using m/z 168 as a quantifier (fragment) ion. A linear (R2> 0.999) calibration curve in urine was obtained over a range 0.2-10 ng mL(-1). This method is about 20 times more sensitive than previously described procedures, and is characterized by high accuracy (mean 90%) and good reproducibility (RSD <10%). The optimized method was applied to determination of 8OHdG in 18 urinary samples derived from three healthy volunteers. 8OHdG urinary excretion ranged from 3.0-7.9 microg/day, and a large intra-individual variation was found. This method, which effectively circumvents the need for isotopically labeled 8OHdG (internal standard), is suitable for routine monitoring of exposure to DNA-damaging factors in a large number of subjects.  相似文献   

10.
In this work, a simple isocratic reversed-phase HPLC method for determination of alpha-tocopherol in human erythrocytes has been developed and validated. After separation of plasma the erythrocytes were washed three times with 0.9% sodium chloride containing 0.01% butylated hydroxytoluene (BHT) as antioxidant and then were diluted 1:1 (v/v) with the same solution. In the liquid-liquid extraction (LLE) procedure, 2500 microL of n-hexane was added to 500 microL of erythrocytes. After 2 min this mixture was deproteinized by addition of cool ethanol (500 microL, 5 min) denatured with 5% methanol containing alpha-tocopherol acetate (20 micromol L(-1)), as internal standard, and then extracted for 5 min by vortex mixing. After centrifugation (10 min, 1600xg) an aliquot (2000 microL) of the clean extract was separated and evaporated under nitrogen. The residue was dissolved in 400 microL methanol and analysed by reversed-phase HPLC on a 4.6 mmx150 mm, 5 microm Pecosphere C18 column; the mobile phase was 100% methanol, flow rate 1.2 mL min(-1). The volume injected was 100 microL and detection was by diode-array detector at a wavelength of 295 nm. The extraction recovery of alpha-tocopherol from human erythrocytes was 100.0+/-2.0%. The detection limit was 0.1 micromol L(-1) and a linear calibration plot was obtained in the concentration range 0.5-20.0 micromol L(-1). Within determination precision was 5.2% RSD (n=10), between determination precision was 6.1% RSD (n=10). The method was applied successfully in a clinical study of patients with acute pancreatitis and for determination of the reference values in the healthy Czech population.  相似文献   

11.
A two-valve sub-ambient temperature-promoted reversed-phase packed-capillary liquid-chromatography column-switching system has been tailored for sensitive determination of hydrophobic compounds. Such compounds are not easily dissolved in solvent mixtures of non-eluting properties that traditionally are used for solute enrichment in reversed-phase liquid chromatography. Enrichment-column solute focusing of large sample volumes was promoted by use of sub-ambient temperatures only, allowing the use of sample solvents that were stronger or equal to the mobile phase solvent strength. Subsequent column switching and enrichment-column temperature increment provided efficient low-dispersion back-flushed enrichment-column solute desorption onto the analytical column, where the solute was subjected to temperature-programmed gradient action. The antioxidant, Irganox 1076 (octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) extracted from low density polyethylene with 100% acetonitrile served as a hydrophobic model compound. The mobile phase consisted of acetonitrile containing 10 mM triethylamine and formic acid, and the 0.25 mm id enrichment-column and analytical column in lengths of 27 and 250 mm, respectively, were packed with 3.5 microm Kromasil C18 particles. Sample volumes of up to 500 microL were successfully focused on the enrichment column at 5 degrees C using loading flow rates of up to 40 microL min(-1) prior to temperature programming to 90 degrees C. The concentration limit of detection of Irganox 1076 was 6 ng mL(-1) when using an injection volume of 500 microL. The within-assay precision was in the range 3.5-6.8% (n = 6) while the between-day precision was 7.5% (n = 3) relative standard deviation. The method was linear within the investigated mass range 3-100 ng (R2 = 0.9993).  相似文献   

12.
A liquid chromatographic (LC) method is described for determination of total vitamin B6 in soy-based infant formula. Total vitamin B6 is quantitated by using ion-pair LC after precolumn transformation of phosphorylated and free vitamers into pyridoxol. The limit of detection is 0.3 ng and the limit of quantitation is 1.0 ng on-column (injection volume = 100 microL). Linear response ranged from 39 to 616 ng/mL (r2 = 0.99986). Analysis of a soy-based infant formula control fortified at 6 different concentration levels gave recoveries that averaged 104%. Assay of SRM 1846 gave results within the certified range (8.6 +/- 0.086 mg/kg versus the certified value of 8.4 +/- 1.0 mg/kg). The method provides a rapid and specific assay for the analysis of total vitamin B6 in fortified soy-based infant formula.  相似文献   

13.
Sensitive and reproducible methods for the determination of oxycodone, oxymorphone and noroxycodone in Ringer solution, rat plasma and rat brain tissue by liquid chromatography/mass spectrometry are described. Deuterated analogs of the substances were used as internal standards. Samples in Ringer solution were analyzed by direct injection of 10 microL Ringer solution diluted by an equal volume of water. The limit of quantification was 0.5 ng/mL and the method was linear in the range of 0.5-150 ng/mL for all substances. To analyze oxycodone and oxymorphone in rat plasma, 50 microL of plasma were precipitated with acetonitrile, and the supernatant was directly injected onto the column. To analyze oxycodone, oxymorphone and noroxycodone in rat plasma, 100 microL of rat plasma were subjected to a C18 solid-phase extraction (SPE) procedure, before reconstituting in mobile phase and injection onto the column. For both methods the limit of quantification in rat plasma was 0.5 ng/mL and the methods were linear in the range of 0.5-250 ng/mL for all substances. To analyze the content of oxycodone, oxymorphone and noroxycodone in rat brain tissue, 100 microL of the brain homogenate supernatant were subjected to a C18 SPE procedure. The limit of quantification of oxycodone was 20 ng/g brain, and for oxymorphone and noroxycodone 4 ng/g brain, and the method was linear in the range of 20-1000 ng/g brain for oxycodone and 4-1000 ng/g brain for oxymorphone and noroxycodone. All methods utilized a mobile phase of 5 mM ammonium acetate in 45% acetonitrile, and a SB-CN column was used for separation. The total run time of all methods was 9 min. The intra-day precision and accuracy were <11.3% and <+/-14.9%, respectively, and the inter-day precision and accuracy were <14.9% and <+/-6.5%, respectively, for all the concentrations and matrices described.  相似文献   

14.
A simple and sensitive HPLC method was developed and validated for the determination of four frequently prescribed 1,4-benzodiazepines: alprazolam (ALP), bromazepam (BRZ), diazepam (DZP), and flunitrazepam (FNZ). Separation was achieved on an Inertsil C8 analytical (250 mm x 4 mm, 5 microm) column, after selective extraction of benzodiazepine drugs from biological matrices by means of SPE. Isocratic elution was performed with a mobile phase consisting of CH3COONH4, 0.05 M CH3OH, and CH3CN (33:57:10 by volume). Quantification was performed at 240 nm with mefenamic acid (6 ng/microL) as the internal standard. DSC-18 Supelco cartridges provided high absolute recoveries (81-115%). The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, and sensitivity. Repeatability (n = 8) and between-day precision (n = 8) revealed RSD <12%. Recoveries from biological samples ranged from 81.2 to 115%. The detection limit of the method was calculated as 3.3-10.2 ng in blood plasma and 2.6-12.6 ng in urine for 20 microL injection volume. The method was applied to spiked biological matrices. Moreover, the method was applied to real samples of urine after an oral administration.  相似文献   

15.
A direct, accurate, and sensitive chromatographic analytical method for the quantitative determination of five fluoroquinolones (enoxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin) in chicken whole blood is proposed in the present study. For quantitative determination lamotrigine was used as internal standard at a concentration of 20 ng/microL. The developed method was successfully applied to the determination of enrofloxacin, as the main component of commercially available veterinary drugs. Fluoroquinolone antibiotics were separated on an Inertsil (250 x 4 mm) C8, 5 microm, analytical column, at ambient temperature. The mobile phase consisted of a mixture of citric acid (0.4 mol L(-1))-CH3OH-CH3CN (87:9:4% v/v) leading to retention times less than 14 min, at a flow rate 1.4 mL min(-1). UV detection at 275 nm provided limits of detection of 2 ng/mL per 20 microL injected volume for enoxacin, norfloxacin, and ciprofloxacin, 0.4 ng/mL for ofloxacin, and 4 ng/mL for enrofloxacin. Preparation of chicken blood samples is based on the deproteinization with acetonitrile while the pharmaceutical drug was simply diluted with water. Peaks of examined analytes in real samples were identified by means of a photodiode array detector. The method was validated in terms of within-day (n=6) precision and accuracy after chicken whole blood sample deproteinization by CH3CN. Using 50 microL of chicken blood sample, recovery rates at fortification levels of 40, 60, and 80 ng ranged from 86.7% to 103.7%. The applicability of the method was evaluated using real samples from chicken under fluoroquinolone treatment.  相似文献   

16.
The aim of the present study was to attempt to describe the procedure of isolation, purification, enrichment and determination of 4-n-nonylphenol (4-n-NP) and 4-tert-octylphenol (4-t-OP) in water and biological samples (fish tissue). There were five procedures of solid phase extraction (SPE) tested using different sorbents for the isolation of analytes from water samples. Moreover, we isolated these chemicals from biological matrices with the aid of various extraction methods. The purpose of it was to perform an optimisation of ultrasonic bath, accelerated solvent extraction (ASE) and solid phase extraction process of alkylphenols from biological samples, through the choice of selective sorbents (octadecyl, octadecyl end-capped and amine) and search solvents (methylene chloride, methanol, hexane). Reversed-phase HPLC with diode array detection was used for the determination of 4-n-NP and 4-t-OP in water and fish tissue samples. Sensitivity was evaluated by determining the limit of detection (LOD=0.06 and 0.04ng microL(-1)) and limit of quantification (LOQ=0.18 and 0.16ng microL(-1)) of 4-NP and 4-t-OP, respectively. A series of standard solutions for 4-n-NP and 4-t-OP provided the basis for plotting an analytical curve and obtaining a linear dependence in the range of approximately 1-25ng microL(-1). The best efficiencies obtained for 4-n-NP and 4-t-OP in water samples were 76.65% (+/-1.49) and 83.08% (+/-3.73), respectively. In the case of fish tissue, different situation was observed because the obtained values were considerably lower, being 68.32% for 4-t-OP using hexane (program 1) as solvent and 72.35% (program 2) for 4-n-NP using acetonitrile.  相似文献   

17.
Lin S  Zheng C  Zu H 《Talanta》1995,42(8):1143-1149
A sensitive method for the determination of strontium has been developed. In this work strontium was determined by flame atomic absorption spectrometry using a continuous copreconcentration dissolution procedure based on the formation of lead sulfate followed by elution with hot EDTA solution. Manifold parameters and chemical conditions are described in detail. A concentration factor of up to 61 can be achieved at a sampling rate of 20-30 h(-1). The detection limit for strontium was 0.9 ng ml(-1) (3sigma) and the relative standard deviation was 3.5% (n = 8) at a concentration level of 100 ng ml(-1).  相似文献   

18.
Sabry SM 《Talanta》1999,50(1):133-140
A sensitive method for the measurement of phenazopyridine hydrochloride (PAP) by differential pulse polarography (DPP) based on adsorptive stripping technique, using a hanging mercury drop electrode (HMDE) is described. The voltammetric peak is obtained at -0.760 V, which corresponds to the reduction of the azo group in Britton-Robinson buffer. The redox behaviour is reversible. Optimum conditions were found to be: accumulation potential -50 mV (vs. Ag/AgCl), accumulation time 60 s, scan rate 5 mV s(-1), pulse amplitude -100 mV and supporting electrolyte Britton-Robinson buffer (0.04 M, pH=11). The relative standard deviation (at 20 ng ml(-1) level) was +/-0.6% for six measurements. The calculated detection limit was 0.0299 ng ml(-1) with a 60-s accumulation time. The applicability of such a method was evaluated through the assay of PAP in human plasma and urine samples after a simple extraction procedure and in pharmaceutical preparation. The mean recovery was 97+/-2 (100 ng ml(-1) plasma).  相似文献   

19.
A sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the investigation of the pharmacokinetics of 20(R)-ginsenoside Rg3 in dog. The plasma samples were pretreated by liquid-liquid extraction and analyzed using LC/MS/MS with an electrospray ionization interface. Dioscin was used as the internal standard. The method had a lower limit of quantitation of 0.5 ng/mL for Rg3 in 200 microL of plasma or 2 ng/mL in 100 microL of plasma, which offered a satisfactory sensitivity for the determination of Rg3 in plasma. The intra- and inter-day precisions were measured to be below 8% and accuracy between -1.5 and 1.4% for all quality control samples. This quantitation method was successfully applied to pharmacokinetic studies of Rg3 after both an oral and an intravenous administration to beagle dogs. No Rh2 and protopanaxadiol were detected in plasma.  相似文献   

20.
Decanoic acid reverse micelle-based coacervates were proposed for the extraction of bisphenol A (BPA) from canned vegetables and fruits prior to its determination by liquid chromatography and fluorescence detection at lambda(exc) = 276 nm and lambda(em) = 306 nm. The procedure involved the extraction of minute quantities (300-700 mg) of homogenized food sample with an aqueous solution containing 10% of THF and 0.5% of decanoic acid, conditions under which the coacervate (around 340 microL) formed in situ and instantaneously. The overall sample treatment, which included extraction and centrifugation, took about 25-30 min, and several samples could be simultaneously treated using conventional lab equipment. No clean-up or solvent evaporation were required. Extraction efficiencies mainly depended on the decanoic acid and THF concentration in the aqueous solution and were not affected by the pH or the temperature in the ranges studied (1-4 and 20-60 degrees C, respectively). Recoveries in samples ranged between about 81 and 96%. The precision of the method, expressed as relative standard deviation, was about 3% and the quantitation limit was around 9 ng g(-1), which was far below the current specific migration limit (SML) set for BPA by the EU Commission (600 ng g(-1)). The method was successfully applied to the determination of BPA in the solid content of canned fruit salad, peaches in syrup, mango slices, red peppers, sweetcorn, green beans and peas. BPA was present at concentrations in the range from 7.8 to 24.4 ng g(-1) in canned fruits and from 55 to 103 ng g(-1) in canned vegetables.  相似文献   

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