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1.
Pilar Viñas Carmen López-Erroz Francisco Joseé Cerdán Natalia Campillo Manuel Hernández-Córdoba 《Mikrochimica acta》2000,134(1-2):83-87
A new fluorimetric procedure for the determination of thiamine using flow injection analysis is proposed. The method is based
on the derivatization reaction of the primary amine group with o-phthalaldehyde in the presence of 2-mercaptoethanol using fluorimetric detection. The calibration graph based on peak area
was linear in the range 0.2–6 ng mL−1. The detection limit was close to 0.1 ng mL−1. The method was applied to the determination of the vitamin in commercial pharmaceutical preparations.
Received March 31, 1999. Revision October 15, 1999. 相似文献
2.
Özlem Aksu Dönmez Abdürrezzak Bozdoğan Gönül Kunt 《Monatshefte für Chemie / Chemical Monthly》2006,137(9):1163-1168
Summary. A partial least-squares calibration (PLS) method has been developed for simultaneous quantitative determination of escin (ES) and diethylamine salicylate (DAS) in pharmaceutical preparations. The resolution of these mixtures has been accomplished without prior separation or derivatisation,
by using partial least-squares (PLS-2) regression analysis of electronic absorption spectral data. The experimental calibration
matrix was constructed with 9 samples. The concentration ranges considered were 10, 20, 30 (ES) and 40, 50, 60 (DAS) μg cm−3. The absorbances were recorded between 200 and 325 nm every 5 nm. Proposed method was compared with conventional spectrophotometric
method. The results show that PLS-2 is a simple, rapid, and accurate method applied to the determination of these compounds
in pharmaceuticals. 相似文献
3.
This paper reports the construction and evaluation of a dopamine sensitive electrode and its usefulness for the determination
of this compound by direct potentiometry in pharmaceutical preparations. The electrode comprised a carboxylated poly(vinyl
chloride) membrane based on β-cyclodextrine dissolved in 2-fluoro-2-nitrodiphenyl ether and using tetrakis(p-chlorophenyl)
borate as a fixed anionic site. For comparison purposes membranes with similar composition but including normal high molecular
weight PVC were also prepared.
The electrodes including carboxylated poly(vinyl chloride) presented linear response within the concentration range of 5×10−5 and 10−1 mol dm−3 of dopamine with a slope of about 59 mV decade−1 of activity, in the pH range of 2 to 7.5 units. The response time was less than 15 seconds. Selectivity coefficients for
different interferents including sodium, potassium, ammonium, lithium, epinephrine and norepinephrine were evaluated using
the separated solution method and no significant interferences were observed. The electrode displays useful analytical characteristics
for the direct determination of dopamine in pharmaceutical preparations. Results with an average recovery of 98.6±0.3% were
obtained.
Received May 28, 1998. Revision March 2, 1999. 相似文献
4.
A novel flow injection chemiluminescence (CL) system for the determinati on of pipemidic acid is described. It is based on
the direct CL reaction of pipemidic acid and Co(III) in acid medium. The unstable Co(III) was on-line electrogenerated by
constant current electrolysis. The CL intensity was linear with pipemidic acid concentration in the range of 0.01∼100 μg/ml,
the determination limit was 3.3×10−9 g/mL. The whole process could be complete d in 1 min with a relative standard deviation of 3.2%. The proposed method is suitable
for automatic and continuous analysis and has been applied successfully to the analysis of pipemidic acid in a pharmaceutical
preparation.
Received November 22, 1999. Revision March 24, 2000. 相似文献
5.
The chemiluminescence (CL) of peracetic acid (PAA) in alkaline medium is very weak but is strongly enhanced after the addition
of dihydralazine sulfate (DHZS). Based on this phenomenon, a simple, rapid and highly sensitive flow-injection CL method for
the determination of DHZS was developed. The CL emission was linearly related to the DHZS concentration in the range of 20–4000 ng mL−1 with a detection limit (3σ) of 1.2 ng mL−1. As a preliminary application, the proposed method was successfully applied to the determination of DHZS in pharmaceutical
preparations; the recovery of DHZS in human urine was between 96.5% and 102.2%. A detailed CL mechanism was proposed and singlet
molecular oxygen (1O2) was suggested to be produced in the CL reaction process. 相似文献
6.
A sensitive catalytic method is developed for the spectrophotometric determination of oxalic acid. It is based on the catalytic
action of oxalic acid on a new indicator reaction – the oxidation of Bromophenol Blue by dichromate in dilute sulfuric acid
medium. The reaction rate is monitored spectrophotometrically by measuring the absorbance at 600 nm after quenching the reaction
with sodium hydroxide. A calibration graph from 0.1 to 8.0 μg mL−1 of oxalic acid and a detection limit of 0.04 μg mL−1 was obtained. The applicability of this method was demonstrated by the determination of oxalic acid in water extracts from
vegetables such as spinach, mushrooms and fresh kidney beans.
Received October 18, 1999. Revision June 14, 2000. 相似文献
7.
Alaa S. Amin 《Mikrochimica acta》2000,134(1-2):89-94
A simple, rapid, accurate and sensitive spectrophotometric method for the determination of norfloxacin (NRF), ofloxacin (OFL)
and ciprofloxacin (CPF) is described. This method is based on the formation of an ion pair with sudan III in aqueous-acetone
medium [40% (v/v) acetone]. The coloured products are measured at 567, 565 and 566 nm for NRF, OFL and CPF, respectively.
The optimization of various experimental conditions is described. Beer’s law is obeyed in the range 0.4–12.0, 0.4–8.8 and
0.4–10.4 ;μg mL−1 of NRF, OFL and CPF, respectively. For more accurate results, Ringbom optimum concentration ranges were 0.8–11.2, 0.6–8.5
and 0.8–10.0 μg mL−1, respectively. The results obtained showed good recoveries of ±1.2, ±1.5 and ±1.7% with relative standard deviations of 0.67,
0.83 and 1.08% for NRF, OFL, and CPF, respectively. The molar absorptivity and Sandell sensitivity were also calculated. Applications
of the proposed method to representative pharmaceutical formulations are successfully presented.
Received April 30, 1999. Revision November 25, 1999. 相似文献
8.
Three simple and sensitive colorimetric methods (A–C) for the determination of melatonin in bulk samples and in pharmaceutical
formulations are described. They are based on the formation of coloured species by reaction of ninhydrin with the drug (method
A, λmax 397 nm) by oxidation of the indol moiety in melatonin with potassium persulphate (method B, λmax 450 nm) or by reduction of osmium (VIII) (method C, λmax 516 nm). Regression analysis of Beer-Lambert plots showed good correlations in concentration ranges between 0.8–14.2, 70.0–140.0
and 2.0–40.0 μg/mL for methods A, B and C, respectively. The molar absorptivity, Sandell sensitivity and detection limit were
calculated. For more accurate analysis, Ringbom optimum concentration ranges were calculated. The validity of the proposed
methods was tested by analysing pharmaceutical formulations containing melatonin. The relative standard deviations were ≤ 0.95%
with recoveries 99.0–101.33%.
Received October 20, 1999. Revision February 10, 1999. 相似文献
9.
?zlem Aksu D?nmez Abdürrezzak Bozdo?an G?nül Kunt 《Monatshefte für Chemie / Chemical Monthly》2006,35(6):1163-1168
A partial least-squares calibration (PLS) method has been developed for simultaneous quantitative determination of escin (ES) and diethylamine salicylate (DAS) in pharmaceutical preparations. The resolution of these mixtures has been accomplished without prior separation or derivatisation,
by using partial least-squares (PLS-2) regression analysis of electronic absorption spectral data. The experimental calibration
matrix was constructed with 9 samples. The concentration ranges considered were 10, 20, 30 (ES) and 40, 50, 60 (DAS) μg cm−3. The absorbances were recorded between 200 and 325 nm every 5 nm. Proposed method was compared with conventional spectrophotometric
method. The results show that PLS-2 is a simple, rapid, and accurate method applied to the determination of these compounds
in pharmaceuticals. 相似文献
10.
A differential pulse voltammetric method for the determination of nitrate has been described, which is applicable to the
analysis of natural water samples with nitrate levels greater than 2.8 × 10−6 M. A reduction peak for the nitrate ions at a freshly copper plated glassy carbon electrode was observed at about −0.50 V
vs Ag ∣AgCl∣KClsatd electrode in a solution of 2.0 × 10−2 M Cu2+, 0.5 M H2SO4 and 1.0 × 10−3 M KCl and exploited for analytical purposes. The working linear range was established by regression analysis and found to
extend from 2.8 ×10−6 M to 8.0 × 10−5 M. The proposed method was applied for the determination of nitrate in natural waters. The detection limit of the method
was 2.8 × 10−6 M and the sensitivity was 0.9683 A·L/mol. The possible interferences by some ions such as phosphate, nitrite and some halides
were determined and found to lead to shifts of the peak position and increasing the peak heights.
Received March 15, 1999. Revision July 9, 1999. 相似文献
11.
Two simple, fast, accurate and precise methods for the determination of six phenothiazines and a number of their pharmaceutical
formulations are described. The titrimetric method involves the oxidation of the drugs by metavanadate in sulphuric acid medium
and titration of vanadium(IV) formed, with cerium(IV) using ferroin indicator and acetone as catalyst. In spectrophotometry,
vanadium(IV) formed was reacted with ferriin and the resulting ferroin measured at 510 nm. Phenothiazines in the ranges 5–100 mg
and 2.5–25.0 μg mL−1 can be determined by titrimetry and spectrophotometry, respectively, with detection limits of 0.96–2.05 mg and 0.0359–0.0565 μg mL−1, respectively. Both methods were applied successfully to the determination of the studied drugs in pharmaceutical preparations.
The reliability of the assays was established by parallel determination by the official methods of British Pharmacopoeia and
the results being statistically evaluated.
Received September 26, 2000. Revision March 25, 2001. 相似文献
12.
Paraskevas D. Tzanavaras Demetrius G. Themelis Anastasios Economou Georgios Theodoridis 《Mikrochimica acta》2003,142(1-2):55-62
Two new simple and rapid methods are reported for the accurate and precise spectrophotometric determination of captopril
(CPL) using flow (FI) and sequential injection (SI) analysis. The methods are based on the fast oxidation of CPL by Fe(III).
The produced Fe(II) reacts with 2,2′-dipyridyl-2-pyridylhydrazone (DPPH) in acidic medium to form a colored complex which
is monitored spectrophotometrically at 535 nm. Both methods allow the determination of the analyte up to 1000 mg L−1 at a sampling rate of 120 and 60 injections per hour for FI and SI, respectively. The methods are very precise [s
r=0.8 and 1.2% at 500 mg L−1 CPL (n=12) for FI and SI, respectively] and the 3σ detection limits (c
L=4.0 and 7.0 mg L1, respectively) are quite satisfactory. Their application to a variety of anti-hypertensive commercial pharmaceutical formulations
showed excellent results (relative errors, e
r, < ± 1.6% in all cases compared to an official HPLC method), while common pharmaceutical excipients were found not to interfere.
Recovery experiments further verified the accuracy of the developed methods, as the percent recoveries were in the range of
98.1–102.5%.
Author for correspondence. E-mail: themelis@chem.auth.gr
Received May 9, 2002; accepted January 8, 2003
Published online May 5, 2003 相似文献
13.
Mohammad A. Mottaleb 《Mikrochimica acta》1999,132(1):31-39
A reversed-phase high performance liquid chromatography (RP-HPLC) method, with acetic acid and sodium perchlorate phase modifiers,
was developed to separate a mixture of linear alkylbenzene sulphonates (LAS), containing 10 to 13 carbon atoms. The effects
of methanol-water compositions and concentrations of used modifiers were investigated and compared. The separation achieved
with 50 mg L−1 acetic acid was found satisfactory whereas a concentration of 10 g L−1 sodium perchlorate was preferred. Chromatograms obtained with UV and Fourier transform infrared (FTIR) detection showed almost
similar features and HPLC-FTIR interface spectra of LAS components exhibited excellent agreement of absorption features to
those of standard FTIR spectrum and no thermal degradation was found to occur.
Received May 20, 1998 Revision March 25, 1999. 相似文献
14.
Ai-Lin Liu Jia-Dong Wang Wei Chen Xing-Hua Xia Yuan-Zhong Chen Xin-Hua Lin 《Journal of Solid State Electrochemistry》2012,16(4):1343-1351
A simple, rapid, sensitive, and accurate method for simultaneous electrochemical determination of procaine and its metabolite
(p-aminobenzoic acid, PABA) for pharmaceutical quality control and pharmacokinetic research was developed using a graphite paste
electrode. The differential pulse voltammetric results revealed that procaine and p-aminobenzoic acid, respectively, showed well-defined anodic oxidation peaks on a carbon paste electrode with a current peak
separation of 155 mV at a scan rate of 100 mV s−1. This well separation of the current peaks for these two compounds in voltammetry enables us to simultaneously determine
them. Good linearity (r > 0.998) between oxidation peak current and concentration was obtained in the range of 5.0 × 10−7–5.0 × 10−5 M for procaine and 5.0 × 10−7–2.0 × 10−5 M for PABA in pH 4.50 acetate buffer solution. The detection limit for both analytes is 5 × 10−8 M (S/N = 3:1). The present voltammetric method has been successfully used to determine trace p-aminobenzoic acid in procaine hydrochloride injection and procaine in plasma with a linear relationship of current to its
concentration ranging from 1.0 × 10−6 to 5.0 × 10−5 M (correlation coefficient of 0.9981) with a low detection limit of 5.0 × 10−7 M (S/N = 3:1). This validated method is promising to the study of pharmacokinetics in Sprague–Dawley rat and rabbit plasma after
an intravenous administration of procaine hydrochloride injection. 相似文献
15.
A novel ion-selective sensor for procaine hydrochloride has been proposed and applied successfully to analysis of pharmaceutical
preparations. The sensor is based on modification of the Ag-electrode of an AT-cut piezoelectric quartz crystal with a PVC
membrane containing procaine tetraphenylborate. A linear relation between the logarithm of the response frequency and the
logarithm of the procaine hydrochloride concentration was found experimentally and could be explained by combination of a
modified Sauerbrey equation and the Freundlich isotherm. The detection range was from 8.3 × 10−8 to 5.0 × 10−3 M with a detection limit of 8.3 × 10−8 M. The selectivity of the sensor and the influence of experimental parameters such as solution pH and detection time were
investigated.
Received February 10, 1999. Revision October 10, 1999. 相似文献
16.
Leonardo Sena Gomes Teixeira Antônio Celso Spínola Costa Júlio César Rosa Assis Sérgio Luis Costa Ferreira Mauro Korn 《Mikrochimica acta》2001,137(1-2):29-33
A new sensitive method exploiting solid-phase spectrophotometry is proposed for the determination of cobalt in pharmaceutical
preparations. The chromogenic reagent 1-(2-thiazolylazo)-2-naphthol (TAN) was immobilized on C18 bonded silica loaded into
a home-made cell with 1.5 mm of optical path for cobalt determination. Cobalt(II) reacts with TAN on C18 material, at pH 6.0–7.5,
to give a coloured complex which has maximum absorption at 572 nm. In this way, the sample was passed through the cell and
Co(II) ions were quantitatively retained on the solid-phase. After the direct measurement of light-absorption in the solid
phase, only the cobalt was eluted with 0.1 mol L−1 hydrochloric acid. The cell was washed with water and then another sample solution could be passed through the cell. The
procedure allowed the determination of cobalt in the range of 10–160 μg L−1 with coefficient of variation of 4.7% (n=10) and apparent molar absorptivity of 2.62 × 106 L mol−1 cm−1 using sample volume of 3-mL.
Received May 15, 2000. Revision August 28, 2000. 相似文献
17.
Selective Indicator Reaction for Kinetic Determination of Traces of Manganese(II), Ribavirin and Tiazofurin 总被引:1,自引:0,他引:1
Gordana A. Milovanović Mira M. Čakar Nevenka B. Vučić Milan Jokanović 《Mikrochimica acta》2000,135(3-4):173-178
In this work it was established that, in the presence of ammonium carbonate, traces of manganese(II) catalyse the oxidation
of Nile Blue A by hydrogen peroxide, which enables its kinetic determination in the concentration range from 6.6 to 65.9 ng
cm−3, the detection limit being 8.0 × 10−2 ng cm−3. Antiviral/antitumour substances modify the catalytic activity of manganese(II): 1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide,
ribavirin, increases the catalytic effect of manganese(II), while 2-β-D-ribofuranosyl-thiazole-4-carboxamide, tiazofurin,
acts as an inhibitor. On the basis of these effects, a kinetic method for determining ribavirin concentrations from 0.5 × 10−1 to 4.0 × 10−1 μg cm−3 and tiazofurin concentrations from 0.3 to 2.6 μg cm−3 is proposed. The kinetics of the indicator reaction were studied in the presence of the substances examined, the kinetic
equations established, and the constants of the corresponding reaction rates calculated. The effect of temperature on these
reactions was also investigated. The method was applied to the determination of manganese(II) in mineral water and ribavirin
in pharmaceutical preparations.
Received December 16, 1999. Revision June 6, 2000. 相似文献
18.
Summary. A new simple, rapid, sensitive, and selective method is proposed for the microdetermination of mercury. Mercury(II) forms
insoluble complexes with 2,3-dichloro-6-(2-hydroxy-3,5-dinitrophenylazo)-quinoxaline (1), 2,3-dichloro-6-(5-amino-3-carboxy-2-hydroxy-phenylazo)-quinoxaline (2), 2,3-dichloro-6-(2,7-dihydroxynaphth-1-ylazo)-quinoxaline (3), and 2,3-dichloro-6-(3-carboxy-2-hydroxy-naphth-1-ylazo)-quinoxaline (4) in aqueous acidic medium; the complexes can be made soluble by the action of an anionic surfactant. The solution of the
pink coloured compounds is stable for at least 24 h. Beer’s law is obeyed over the concentration range from 0.1 to 2.8 μg · cm−3 of mercury. For a more accurate analysis, Ringbom optimum concentration ranges were found to be 0.25–2.5 μg · cm−3. The molar absorpitivity, Sandell sensitivity, and relative standard deviations were also calculated. A slight interference from Pd2+ and Cd2+ is exhibited by the first three ligands, whereas the last one is only negligibly affected by these metal ions. Strong interference
from Ag(I) is evident for all ligands, whereas alkali, alkaline earth, and other transition metals tested posed negligible
interference. 15 μg · cm−3 of Cd2+ and Pd2+ or 10 μg · cm−3 of Ag+ can be tolerated if 1.0 mg of potassium bromide and 2.0 mg of citrate as masking agents are added for the determination of
1.5 μg · cm−3 of mercury(II). The method was applied to the determination of methyl- and ethylmercury chloride and the analysis of environmental
water samples.
Received August 7, 2000. Accepted (revised) October 18, 2000 相似文献
19.
Andreas Rahm Evgeni M. Kaidashev Heidemarie Schmidt Mariana Diaconu Andreas Pöppl Rolf Böttcher Christoph Meinecke Tilman Butz Michael Lorenz Marius Grundmann 《Mikrochimica acta》2006,153(1-2):21-25
A flow injection chemiluminescence method is proposed for the determination of cobalt, based on the strong catalytic effect
of Cobalt(II) (1,10-phenanthroline)3 complex on the lucigenin-periodate reaction in alkaline medium. Under the optimum experimental conditions, the chemiluminescence
signal responded linearly to the concentration of cobalt(II) in the 1.0 × 10−9–3.0 × 10−7 g mL−1 range with a detection limit of 4.4 × 10−10 g mL−1 cobalt(II). The relative standard deviation for the determination of 5.0 × 10−8 g mL−1 of cobalt was 2.3% in eleven replicated measurements. The method was successfully applied to the determination of cobalt(II)
in pharmaceutical preparations. 相似文献
20.
Determination of chromium(VI) and total chromium in water by in-electrode coulometric titration in a porous glassy carbon electrode 总被引:1,自引:0,他引:1
Chromium(VI) is determined through its direct electrochemical reduction in the bulk of a porous glassy carbon electrode. An
electrode filled with the acidified sample and Cr(VI) is reduced by means of a constant current whereas the potential of the
electrode is monitored. The limits of detection and quantification were found to be 1.9 and 6.0 μg · L−1, resp. The linear range, repeatability and reproducibility were found to be 5–500 μg · L−1, 1.2, and 1.8%, resp. The influence of Fe(III), Ca(II), Mg(II), sulphates, nitrates, humic acids and surfactants was investigated.
Total chromium was measured after chemical oxidation of Cr(III) to chromate by permanganate. The method was applied to analyses
of water samples. 相似文献