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1.
Cantú MD Toso DR Lacerda CA Lanças FM Carrilho E Queiroz ME 《Analytical and bioanalytical chemistry》2006,386(2):256-263
Simple, sensitive, and reproducible off-line solid-phase microextraction and liquid chromatography (SPME/LC) methods are described
for the determination of seven anticonvulsants and tricyclic antidepressants in human plasma. Factorial design and simplex
methodology were applied in the optimization of the SPME procedure for tricyclic antidepressants analyses. Important factors
in the SPME efficiency are discussed, such as the fiber coatings (both lab-made and commercial), extraction time, pH, ionic
strength, influence of plasma proteins, and desorption conditions. The development of the lab-made fiber coatings, namely,
octadecylsilane, aminosilane, and polyurethane, are further described and applied to anticonvulsants analyses. The investigated
plasmatic range for the evaluated anticonvulsants, using CW-TPR fiber, were the following: phenylethylmalonamide (3.00–40.0 μg
mL−1), phenobarbital (5.00–40.0 μg mL−1), primidone (3.00–40.0 μg mL−1), carbamazepine and carbamazepine-epoxide (2.00–24.0 μg mL−1), phenytoin (2.00–40.0 μg mL−1), and lamotrigine (0.50–12.0 μg mL−1). The antidepressants’ linear plasmatic concentration ranged from 75.0 to 500 ng mL−1 for imipramine, amitriptyline, and desipramine, and from 50.0 to 500 ng mL−1 for nortriptyline, being in all cases, the limit of quantification represented by the lowest value. The precision (interassays)
for all investigated drugs in plasma sample spiked with different concentrations of each analyte and submitted to the described
procedures were lower than 15%. The off-line SPME/LC methodologies developed allow anticonvulsants and antidepressants analyses
from therapeutic to toxic levels for therapeutic drug monitoring. 相似文献
2.
A. Lopez Molinero Alberto Morales Anselmo Villareal Juan R. Castillo 《Fresenius' Journal of Analytical Chemistry》1997,358(5):599-603
The generation of volatile species of silicon as a means to introduce silicon into an inductively coupled plasma has been
studied. It is based on the reaction between silicon and fluoride ions in sulfuric acid media and it was carried out using
different flow injection mountings. The first mounting works with an injection of 100 μL concentrated sulfuric acid and 150
μL silicon standard solution in a continuous 0.05 mol L–1 NaF solution flow. The method shows a linear response between the intensity of emission at 251.611 nm line and the silicon
concentration from 0.1 to 200 μg mL–1, with a reproducibility of 2% and a detection limit of 0.004 μg mL–1. The second mounting produces the volatile species by the reaction between two opposed aerosol flows in a home-made nebulization
chamber. This chamber has a Cross-Flow and a Meinhard nebulizer at either end. A linear response ranging from 0.1 to 1000
μg mL–1 of silicon solution is obtained and the reproducibility rises to 8%.The detection limit reached is 0.02 μg mL–1. The silicon content in real water samples was determined by applying both the above-mentioned methods and a third method
for reference.
Received: 6 November 1996 / Revised: 19 December 1996 / Accepted: 3 January 1997 相似文献
3.
A simple reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination
of the antiepileptic drugs (AEDs) zonisamide (ZNS), primidone (PRI), lamotrigine (LTG), phenobarbital (PB), phenytoin (PHT),
oxcarbazepine (OXC), and carbamazepine (CBZ) and two of their active metabolites, monohydroxycarbamazepine (MHD) and carbamazepine
10,11-epoxide (CBZE) in human plasma. Plasma (100 μL) was pretreated by deproteinization with 300 μL methanol containing 20 μg mL−1 propranolol hydrochloride as internal standard. HPLC was performed on a C8 column (4.6 mm × 250 mm; particle size 5 μm) with methanol–acetonitrile–0.1% trifluoroacetic acid, 235:120:645 (v/v), as mobile phase at a flow rate of 1.5 mL min−1. ZNS, OXC, and CBZ were monitored by UV detection at 235 nm, and PRI, LTG, MHD, PB, PHT, and CBZE by UV detection at 215 nm.
Relationships between response and concentration were linear over the concentration ranges 1–80 μg mL−1 for ZNS, 5–50 μg mL−1 for PRI, 1–25 μg mL−1 for LTG, 1–50 μg mL−1 for MHD, 5–100 μg mL−1 for PB, 1–10 μg mL−1 for CBZE, 0.5–25 μg mL−1 for OXC, 1–50 μg mL−1 for PHT, and 1–25 μg mL−1 for CBZ. Intra-day and inter-day reproducibility were adequate (coefficients of variation were ≤11.6%) and absolute recovery
ranged from 95.2 ± 6.13 to 107.7 ± 7.76% for all the analytes; for the IS recovery was 98.69 ± 1.12%. The method was proved
to be accurate, reproducible, convenient, and suitable for therapeutic monitoring of the nine analytes. 相似文献
4.
A. Ruiz Medina M. L. Fernández de Córdova A. Molina Díaz 《Analytical and bioanalytical chemistry》1999,365(7):619-624
A new, sensitive and very simple spectrofluorimetric biparameter sensor is described for the determination of salicylamide
and/or salicylic acid in pharmaceutical preparations. The method integrates the transitory retention and fluorescence detection
of both compounds on Sephadex QAE A-25 resin packed into a conventional flow-through cell. A monochannel manifold with two
alternative carriers is used. At pH 2.0 (first carrier) salicylic acid is selectively retained on the solid support and after
developing the analytical signal it is desorbed. At pH 11.0 (second carrier) both salicylic acid and salicylamide are simultaneously
and transitorily retained on the solid, the analytical signal now corresponding to both analytes. The monochromators were
tuned at 260 (excitation) and 415 (emission) nm, respectively. The calibration graph for salicylamide is linear over the range
0.01 to 0.32 μg mL–1 and for salicylic acid from 0.04 to 1.0 μg mL–1 in the presence of each other. The relative standard deviation and the sampling frequency for the determination of salicylamide
(0.20 μg mL–1) and salicylic acid (0.50 μg mL–1) were 1.1% and 35 h–1, and 0.9% and 45 h–1, respectively. Good results on application to individual determination or mixture resolution in pharmaceutical samples testify
to the usefulness of the proposed sensor.
Received: 20 April 1999 / Revised: 7 June 1999 / Accepted: 12 June 1999 相似文献
5.
Michael Winklmair Andreas J. Schuetz M. G. Weller Reinhard Niessner 《Fresenius' Journal of Analytical Chemistry》1999,363(7):619-624
A new, sensitive and very simple spectrofluorimetric biparameter sensor is described for the determination of salicylamide
and/or salicylic acid in pharmaceutical preparations. The method integrates the transitory retention and fluorescence detection
of both compounds on Sephadex QAE A-25 resin packed into a conventional flow-through cell. A monochannel manifold with two
alternative carriers is used. At pH 2.0 (first carrier) salicylic acid is selectively retained on the solid support and after
developing the analytical signal it is desorbed. At pH 11.0 (second carrier) both salicylic acid and salicylamide are simultaneously
and transitorily retained on the solid, the analytical signal now corresponding to both analytes. The monochromators were
tuned at 260 (excitation) and 415 (emission) nm, respectively. The calibration graph for salicylamide is linear over the range
0.01 to 0.32 μg mL–1 and for salicylic acid from 0.04 to 1.0 μg mL–1 in the presence of each other. The relative standard deviation and the sampling frequency for the determination of salicylamide
(0.20 μg mL–1) and salicylic acid (0.50 μg mL–1) were 1.1% and 35 h–1, and 0.9% and 45 h–1, respectively. Good results on application to individual determination or mixture resolution in pharmaceutical samples testify
to the usefulness of the proposed sensor.
Received: 20 April 1999 / Revised: 7 June 1999 / Accepted: 12 June 1999 相似文献
6.
Du F Luo X Jiang G Hou S Liu G Ren L Zhang L Huang Q Jie N 《Analytical and bioanalytical chemistry》2007,388(2):489-493
Analysis of triadimenol was carried out using deoxyribonucleic acids (DNA) via the resonance light scattering (RLS) technique.
After adding triadimenol into aqueous medium of pH 1.72, the RLS of DNA was remarkably quenched. A resonance light scattering
peak at 310 nm was found, and the quenched intensity of RLS at this wavelength was proportional to the concentration of triadimenol.
The linear range of the calibration curve was approximately 0–3 μg mL−1 with a detection limit (S/N = 3) of 0.07 μg mL−1. The triadimenol in samples of water, cucumber and human serum was determined. The results were satisfactory, and the recovery
rates were in the range of 96.3–106.0%, 94.8–105.9% and 92.3–100.5%, respectively. The interaction mechanism was also studied. 相似文献
7.
Study of the preconcentration and determination of ultratrace rare earth elements in environmental samples with an ion exchange micro-column 总被引:2,自引:0,他引:2
W. Zhu E. W. B. de Leer M. Kennedy G. J. F. R. Alaerts 《Fresenius' Journal of Analytical Chemistry》1998,360(1):74-80
A study was carried out on the preconcentration of ultratrace rare earth elements (REEs) in environmental samples with a
micro ion-exchange column and determination by inductively coupled plasma mass spectrometry (ICP-MS). The preconcentration
parameters were optimized and the REE recovery was ca. 100% in the pH range 4 to 6 with an ionic strength (μ) less than 0.18.
The ion-exchange column capacity with respect to REEs was estimated as 0.96 mmol/g. The linear response coefficients ranged
from 0.995 to 0.997 at the pg mL–1 level. The concentration in the blank could be minimized (0.09 to 3.1 pg mL–1) if the buffer solution and the water were purified. The detection limits ranged from 0.03 to 0.40 pg mL–1, for a preconcentration factor of 100. The precision and accuracy of the method was evaluated with a synthetic standard solution
and real samples. Results indicated that the REE recovery ranged from 88.1% to 100.2%, and the RSD ranged from 2.7% to 6.7%.
Satisfactory results were achieved when this method was applied for the determination of REEs in raw water, purified water
and tap water, as well as in environmental aquatic samples. Meanwhile, the method is simple and flexible.
Received: 17 January 1997 / Revised: 23 April 1997 / Accepted: 29 April 1997 相似文献
8.
A sensitive analytical method was established for the determination of Th and U in activated concrete samples. The method
combines an anion-exchange separation step with an ICP-MS determination technique. In the ICP-MS measurement, a few μg mL–1 of Al and Ca, a few ng mL–1 of Mn, La, Ce, Nd and Pb and pg mL–1 amounts of Li, Zr, Nb and Ba coexisting in the anion-exchange fraction of Th and U did not interfere. No adverse interference
effects were observed in real sample analyses. The obtained detection limits (3σ, n = 10) of Th and U were 2.3 and 1.8 pg mL–1, respectively. The analytical precisions for ca. 5 μg g–1 Th and ca. 1 μg g–1 U in real activated concrete samples were equally less than 7% RSD. The accuracies obtained by the analysis of GSJ rock standard
samples were –18.1 to 0.4% for the Th determination and –14.0 to –5.7% for the U determination. The method uses the conventional
absolute calibration curve. The internal standard calibration is unnecessary.
Received: 14 March 1999 / Revised: 13 July 1999 / Accepted: 15 July 1999 相似文献
9.
A new method was developed for the simultaneous determination of lidocaine, proline and lomefloxacin in human urine by capillary
electrophoresis-electrochemiluminescence detection with Ru(bpy)3
2+. Conditions of the separation and detection were investigated and optimized. It was proved that 20 mM phosphate buffer at
pH 6.7 could achieve the most favorable resolution, and the high sensitivity of detection was obtained by using the detection
potential at 1.15 V and 5 mM Ru(bpy)3
2+–60 mM phosphate buffer at pH 7.6 in the detection reservoir. The detection limits were 0.02 μg mL−1 for lidocaine, 0.03 μg mL−1 for proline and 0.06 μg mL−1 for lomefloxacin. Relative standard deviations of the ECL intensity and the migration time were 3.5 and 1.1% for 6 μg mL−1 lidocaine, 3.2 and 1.0% for 6 μg mL−1 proline and 3.7 and 1.2% for 6 μg mL−1 lomefloxacin, respectively. A baseline separation for lidocaine, proline and lomefloxacin was achieved within 360 s. The
developed method was successfully applied to determine the amounts of lidocaine, proline and lomefloxacin in human urine.
The recovery and RSD were in the range of 93.3–97.2 and 3.8–4.9%, respectively. 相似文献
10.
Lingli Zhang Yi Chen Mei Lin Guorong Fan Weiquan Zhao Yutian Wu 《Chromatographia》2007,65(5-6):305-311
The quick separation and simultaneous determination of d-amphetamine and diphenhydramine in the quick-acting anti-motion capsules was investigated by capillary zone electrophoresis.
The influence of different parameters (internal standard, injection modes, pH, concentration of the running buffer and applied
voltage) was systematically studied. The two compounds could be well separated within 2.0 min in a 40.2 cm fused-silica capillary
at a separation voltage of 20 kV in a 50 mM phosphate–12.5 mM borate buffer adjusted to pH 5.5. Correlation coefficients for
calibration curves in the range 0.50–1.50 μg mL−1 for d-amphetamine and 2.75–8.25 μg mL−1 for diphenhydramine were higher than 0.999. The limits of detection of d-amphetamine and diphenhydramine were 10.0 and 5.5 ng mL−1 and the recoveries of the compounds in the QAAMC were 99.80 and 99.85%, respectively.
The authors L. Zhang and Y. Chen equally contributed to this work. 相似文献
11.
A high-performance liquid chromatography–UV method for determining DCJW concentration in rat plasma was developed. The method
described was applied to a pharmacokinetics study of intramuscular injection in rats. The plasma samples were deproteinized
with acetonitrile in a one-step extraction. The HPLC assay was carried out using a VP-ODS column and the mobile phase consisting
of acetonitrile–water (80:20, v/v) was used at a flow rate of 1.0 mL min−1 for the effective eluting DCJW. The detection of the analyte peak area was achieved by setting a UV detector at 314 nm with
no interfering plasma peak. The method was fully validated with the following validation parameters: linearity range 0.06–10 μg mL−1 (r > 0.999); absolute recoveries of DCJW were 97.44–103.46% from rat plasma; limit of quantification, 0.06 μg mL−1 and limit of detection, 0.02 μg mL−1. The method was further used to determine the concentration–time profiles of DCJW in the rat plasma following intramuscular
injection of DCJW solution at a dose of 1.2 mg kg−1. Maximum plasma concentration (C
max) and area under the plasma concentration–time curve (AUC) for DCJW were 140.20 ng mL−1 and 2405.28 ng h mL−1. 相似文献
12.
M. A. Campanero A. M. Zamarreño M. Simón M. C. Dios J. R. Azanza 《Chromatographia》1997,46(7-8):374-380
Summary A simple and rapid liquid chromatographic method has been developed for the determination of therapeutic levels of piperacillin
(I) and ceftazidime (II) in human plasma. Plasma and p-propionamidophenol (internal standard) were precipitated with methanol
(I) or 20% trichloroacetic acid (II). The supernatant was analysed on a 5 μm Spherisorb ODS C18 column with acetonitrile-0.05 M phosphate buffer pH 3.8 as mobile phase and ultraviolet detection at 254 nm. The calibration
graph was linear from 10 to 250 μg mL−1, for (I), and from 5 to 200 μg mL−1 for (II). Intra and inter-day CV did no exceed 2.29% for (I), and were 10.76–11.13%–2.00–5.62 for (II) at concentrations
of 10 μg mL−1 and 250 μg mL−1. 相似文献
13.
Tetracycline antibiotics (TCs) such as doxycycline (DOTC), chlortetracycline (CTC), oxytetracycline (OTC), and tetracycline
(TC) react with Cu(II) in pH 3.5 BR buffer medium to form 1:1 cationic chelates, which further react with titan yellow to
form 2:1 ion association complexes. These result in great enhancement of resonance Rayleigh scattering (RRS) and the appearance
of new RRS spectra. The ion association complexes of DOTC, CTC, OTC, and TC have similar spectral characteristics and their
maximum RRS wavelengths are all located at 464 nm. The quantitative determination ranges and the detection limits (3σ) of the four TCs are 0.037–4.8 μg mL−1 and 11.2 ng mL−1 for DOTC, 0.041–5.2 μg mL−1 and 12.4 ng mL−1 for CTC, 0.050–4.8 μg mL−1 and 15.1 ng mL−1 for TC, and 0.088–5.0 μg mL−1 and 26.3 ng mL−1 for OTC, respectively. The optimum reaction conditions, the effects of foreign substances, the structure of ternary complexes,
and the reaction mechanism are discussed. A sensitive, rapid, and simple RRS method for the determination of DOTC has been
developed. 相似文献
14.
A new high-performance liquid chromatography assay was developed for the determination of minocycline in plasma and brain.
A solid–liquid extraction procedure was coupled with a reversed-phase HPLC system. The system requires a mobile phase consisting
of acetonitrile:water:perchloric acid (26:74:0.25, v/v/v) adjusted to pH 2.5 with 5 M sodium hydroxide for elution through a RP8 column (250 × 3.0 mm, i.d.) with UV detection set
at 350 nm. The method proved to be accurate, precise (RSD < 20%) and linear between 0.15–20 μg mL−1 in plasma and 1–20 μg mg−1 in brain. The method was successfully applied to a blood-brain barrier minocycline transport study. 相似文献
15.
Laser-ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) has been established as a very efficient and sensitive
technique for the direct analysis of solids. In this work the capability of LA–ICP–MS was investigated for determination of
trace elements in high-purity graphite. Synthetic laboratory standards with a graphite matrix were prepared for the purpose
of quantifying the analytical results. Doped trace elements, concentration 0.5 μg g–1, in a laboratory standard were determined with an accuracy of 1% to ± 7% and a relative standard deviation (RSD) of 2–13%.
Solution-based calibration was also used for quantitative analysis of high-purity graphite. It was found that such calibration
led to analytical results for trace-element determination in graphite with accuracy similar to that obtained by use of synthetic
laboratory standards for quantification of analytical results. Results from quantitative determination of trace impurities
in a real reactor-graphite sample, using both quantification approaches, were in good agreement. Detection limits for all
elements of interest were determined in the low ng g–1 concentration range. Improvement of detection limits by a factor of 10 was achieved for analyses of high-purity graphite
with LA–ICP–MS under wet plasma conditions, because the lower background signal and increased element sensitivity.
Received: 4 January 2001 / Revised: 27 March 2001 / Accepted: 28 March 2001 相似文献
16.
Lei Zhang Liang Xu Xiao-Jie Tan Qiong-Feng Liao Wei Guo Xiao-Hui Chen Kai-Shun Bi 《Chromatographia》2007,66(1-2):115-120
A sensitive and reliable ion-paired high-performance liquid chromatographic method has been established for the simultaneous
quantification of six major active ingredients, namely baicalin, baicalein, wogonin, oxysophocarpine, oxymatrine and matrine
in the Chinese herbal preparation, Sanwu-Huangqin-Tang. HPLC analyses were performed on a Phenomenex luna C18 column with mobile phase of methanol–acetonitrile–aqueous phosphoric acid at a flow rate of 0.9 mL min−1. The complete separation was achieved within 35 min for the six target constituents. A good linear regression relationship
between peak-areas and concentrations was obtained over the range of 12.10–242.0 μg*mL−1 for baicalin, 5.05–101.0 μg*mL−1 for baicalein, 0.95–19.0 μg*mL−1 for wogonin, 2.75–55.0 μg*mL−1 for oxysophocarpin, 2.75–55.0 μg*mL−1 for oxymatrine and 4.90–98.0 μg*mL−1 for matrine, respectively. The repeatability was evaluated by intra- and inter-day assays with relative standard deviation
(RSD) being less than 5.1%. The recoveries, measured at three concentration levels, varied from 93.8 to 102.1%. The assay
was successfully applied for determination of six bioactive compounds in Sanwu-Huangqin-Tang. The interaction of chemical
constituents was observed when the herbs were used in compatibility. The results indicated that the developed assay method
was rapid, accurate and could be readily utilized as a quality control method for Sanwu-Huangqin-Tang. 相似文献
17.
Protein can greatly enhance the fluorescence of curcumin (CU) in the presence of sodium dodecyl benzene sulfonate (SDBS).
Experiments indicate that under the optimum conditions, the enhanced intensity of fluorescence is proportional to the concentration
of proteins in the range of 0.0050–20.0 μg mL−1 for bovine serum albumin (BSA), 0.080–20.0 μg mL−1 for human serum albumin (HSA), and 0.040–28.0 μg mL−1 for egg albumin (EA). Their detection limits (S/N=3) are 1.4 ng mL−1, 20 ng mL−1, and 16 ng mL−1, respectively. The method has been satisfactorily used for the determination of proteins in actual samples. In comparison
with most of fluorimetric methods, this method is quick and simple, has high sensitivity and good stability. The interaction
mechanism is also studied. 相似文献
18.
Summary Stability indicating high performance liquid chromatography methods have been developed for the assay of meropenem in combination
with either dopamine (A), aminophylline (B), metoclopramide (C) or ranitidine (D) in intravenous fluid mixtures. Separations
B, C and D were performed on a polar endcapped ODS column (150×2 mm) with aqueous, pH 3.0—acetonitrile (89∶11, 88∶12, and
92∶8) eluent and detection at 270, 290, 317 nm respectively. Meropenem was linear over the concentration ranges 126.88–507.50,
131.25–525, and 131.25–525 gmg mL−1. Aminophylline, metoclopramide and ranitidine were linear over the concentration ranges 13–52, 37.5–150, and 25–100 μg mL−1. Separation A was performed on a conventional ODS column (150×2.1 mm) with aqueous, pH 3.0—acetonitrile (85∶15) eluent and
detection at 280 nm. Meropenem and dopamine were linear in the 61.25–245 and 10–40 μg mL−1 ranges, respectively. Accuracy and precision for all methods were 0.20–3.30% and 0.10–1.58%, respectively. Accelerated stability
studies have been carried out on each drug by exposure to acid, base, H2O2, and heat for different time periods. 相似文献
19.
A simple, rapid, and precise reversed-phase high-performance liquid chromatographic method has been developed for simultaneous determination of losartan potassium, ramipril, and hydrochlorothiazide. The three drugs were separated on a 150 mm × 4.6 mm i.d., 5 μm particle, Cosmosil C18 column. The mobile phase was 0.025 m sodium perchlorate–acetonitrile, 62:38 (v/v), containing 0.1% heptanesulphonic acid, pH adjusted to 2.85 with orthophosphoric acid, at a flow rate of 1.0 mL min−1. UV detection was performed at 215 nm. The method was validated for linearity, accuracy, precision, and limit of quantitation. Linearity, accuracy, and precision were acceptable in the ranges 35–65 μg mL−1 for losartan, 1.75–3.25 μg mL−1 for ramipril, and 8.75–16.25 μg mL−1 for hydrochlorothiazide. 相似文献
20.
Alaa S. Amin Ibrahim S. Ahmed Hassan A. Dessouki Hassan A. Mohamed 《Chemical Papers》2010,64(3):278-284
Simple and rapid spectrophotometric methods have been developed for the microdetermination of fluoxetine HCl. The proposed
methods are based on the formation of ion-pair complexes between fluoxetine and bromophenol blue (BPB), bromothymol blue (BTB),
bromocresol green (BCG), and bromocresol purple (BCP) which can be measured at optimum λmax. Optimization of reaction conditions was investigated. Beerșs law was obeyed in the concentration ranges of 0.5–8.0 μg mL−1, whereas optimum concentration as adopted from the Ringbom plots was 0.7–7.7 μg mL−1. The molar absorptivity, Sandell sensitivity, and detection limit were also calculated. The most optimal and sensitive method
was developed using BCG. The correlation coefficient was 0.9988 (n = 6) with a relative standard deviation of 1.25, for six determinations of 4.0 μg mL−1. The proposed methods were successfully applied to the determination of fluoxetine hydrochloride in its dosage forms and
in biological fluids (spiked plasma sample) using the standard addition technique. 相似文献