共查询到20条相似文献,搜索用时 24 毫秒
1.
Two spectrophotometric methods were applied to the simultaneous assay of chlorhexidine hydrochloride (CHL) and lidocaine hydrochloride (LIH) in pharmaceutical formulations. Using derivative spectrophotometry, CHL was determined by measurement of its first derivative
signal at 290 nm (peak to zero amplitude) in the concentration range 5–9 μg/mL, and LIH was analysed by measurement of its
second derivative signals at 272 and 276 nm (peak to peak amplitude) in the concentration range 160–480 μg/mL. With the partial
least-squares (PLS-2), the experimental calibration matrix was constructed using 9 samples. The concentration ranges considered
were 5–7 μg/mL for CHL and 220, 240, 260 μg/mL for LIH. The absorbances were recorded between 240 and 310 nm at every 5 nm. 相似文献
2.
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
3.
Shaista Bano Ayaz Mohd Aftab Aslam Parwaz Khan K. S. Siddiqi 《Journal of Analytical Chemistry》2011,66(7):603-609
Simple, accurate, rapid, and sensitive spectrofluorimetric methods for the determination of levosulpiride in pharmaceutical
formulation were developed utilizing its fluorescence reaction with Fe3+ (method A) and Al3+ (method B). The calibration curves were found to be linear in the concentration range 0.239–3.44 μg/mL and 0.310–2.730 μg/mL with limit
of detection 0.005 μg/mL and 0.0032 μg/mL, respectively, for method A and method B. The reaction conditions were studied and optimized. In addition, the complexation of Mg2+ and Ca2+ was also studied. In all cases, an enhancement in fluorescence emission of levosulpiride upon formation of complex with metal
ions was observed. A 2: 1 (drug: metal) stoichiometry for all the complexes was established. Benesi-Hildebrand method was
applied for calculation of association constant at 25 and 35°C. The thermodynamic parameters obtained in this study revealed
that the interaction process was spontaneous and mainly ΔS-driven. 相似文献
4.
A. Phonchai B. Janchawee S. Prutipanlai S. Thainchaiwattana 《Journal of Analytical Chemistry》2010,65(9):951-959
A methodology for the determination of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and methamphetamine (MA) in seized tablets using gas chromatography with a flame ionization detector (GC-FID) is described. The chromatographic conditions, i.e. gas flow rates and temperatures for the column, injector and detector
were optimized. The optimum chromatographic conditions were as follows: a CP-SIL 24 CB WCOT fused silica capillary column
(30 m × 0.32 mm I.D., 0.25 μm film thickness), N2 carrier gas flowing at 2.6 mL/min, injector temperature at 290°C and detector temperature at 300°C. The oven temperature
was ramped from 80°C at a rate of 20°C/min to final temperature of 270°C (1 min). All analytes were well separated within
7 min with an analysis time of 10.5 min. Calibration curves were linear over the concentration ranges of 3.125–200 μg/mL for
MDMA and 6.25–200 μg/mL for MDA and MA (r > 0.990). The intra- and inter-day precisions for determining all analytes were 2.32–10.38% RSD and 1.15–9.77% RSD, respectively.
The intra- and inter-day accuracies ranged from −19.79 to +17.51% DEV and −6.84 to +5.2% DEV, respectively. The lower limits
of quantification (LLOQs) were 3.125 μg/mL for MDMA and 6.25 μg/mL for MDA and MA. All analytes were stable at room temperature during 24 h but significant
loss occurred after 2-month storage at −20°C. The method was shown to be useful for determining the purity of MDMA in seized
tablets. 相似文献
5.
M. S. Chernov’yants N. V. Aleshina I. V. Burykin 《Journal of Analytical Chemistry》2011,66(3):280-284
A procedure was developed for the determination of the following thioamides based on thiazole, 1,3,4-thiadiazole, 1,2,4-triazole,
and tetrazole: 2-mercaptothiazole (I), 2-mercapto-1,3,4-thiadiazole (II), 2-mercapto-5-methyl-1,3,4-thiadiazole (III), 3-mercapto-1,2,4-triazole (IV), 3-mercapto-4-methyl-1,2,4-triazole (V), and 5-mercapto-1-methyltetrazole (VI). The determination was performed by reversed-phase HPLC on a column (150 × 4 mm) packed with Diaspher-110-C18 (5 μm) using
elution with an acetonitrile-acetate buffer solution (pH 4.70) mixture (5: 95). Detection was performed at the light absorption
maximums of compounds I (320 nm), II (305 nm), III (310 nm), IV (260 nm), V (254 nm), and VI (245 nm). The calibration graphs were linear over the following concentration ranges (μg/mL): 0.47–11.72 (I), 0.47–11.82 (II), 0.53–13.22 (III), 0.40–10.11 (IV), 0.46–11.52 (V), and 0.46–11.62 (VI). The limits of detection were 0.45, 0.43, 0.50, 0.37, 0.41, and 0.42 μg/mL for compounds I–VI, respectively. Conditions for the separation of a mixture of compounds I and III–V and for the quantitative determination of compounds I–VI by capillary zone electrophoresis (CZE) were optimized. CZE was performed on a quartz capillary of size 60 cm (effective length of 50 cm) × 75 μm at a voltage of
20 kV with a borate buffer solution (pH 9.18). The procedure allowed us to evaluate the concentrations of substances in the
ranges of 1.17–93.75 (I), 1.18–94.54 (II), 1.32–105.76 (III), 1.01–101.13 (IV) 1.15–115.16 (V), and 1.16–116.15 (VI) μg/mL with the detection limits of 1.10, 1.11, 1.20, 0.96, 1.01, and 1.02 μg/mL for compounds I–VI, respectively. 相似文献
6.
A simple, reproducible, and sensitive extraction-spectrophotometric method for the determination of fluoxetine (FL) in pharmaceutical formulations is reported. The FLH+ cation, which is formed in an acidic solution, can form an ion-pair with Orange II, (OR II), an anionic dye. The FLH+-OR II− ion pair was quantitatively extracted into dichloromethane solvent and its absorption was measured at 482 nm. The calibration
graph is linear over the FL concentration range of 0.2–9.0 μg/mL and the regression coefficient is 0.9995. The relative standard
deviation (RSD) of ten replicate determinations of 5.0 and 1.4 μg/mL of FL are 0.022 and 0.038, respectively, and the limit
of detection (LOD) of the method is 0.17 μg/mL. The method was successfully applied to the determination of an FL amount in
pharmaceutical formulations (10.0-and 20.0-mg capsules).
The text was submitted by the authors in English. 相似文献
7.
The possibility of the spectrophotometric determination of piroxicam based on the extraction of its ion associate (IA) with the polymethine dye, 5-thiocyanate-1,3,3-trimethyl-2[(1E)-3-[(2E)-1,3,3-trime-thyl-1-H-indol-2-ilidine]-propenyl]-3H-indolium chloride. The maximal recovery of IA with toluene is achieved when pH of the aqueous phase is 8.0–12.0 and the concentration
of the dye is (1.0–2.0) × 10−4. The molar absorption coefficient of IA is 8 × 104, the detection limit of piroxicam is 0.49 μg/mL. A procedure has been developed for the extraction-spectrophotometric determination
of piroxicam in the concentration range 1.0–20.0 μg/mL. 相似文献
8.
M. E. Abd El-Ghaffar D. R. El-Wasseef D. T. El-Sherbiny S. M. El-Ashry 《Journal of Analytical Chemistry》2011,66(5):476-481
A sensitive, simple and rapid spectrofluorimetric method has been developed for the determination of both Fenoterol hydrobromide
(FNT) and Ritodrine hydrochloride (RTH) in pure and dosage forms. The method is based on derivatization using dansyl chloride (DNS-Cl) as fluorogenic agent and
measuring the fluorescence of the products at emission wavelengths of 517 and 515 nm after excitation at 348 and 343 nm for
FNT and RTH, respectively. Different experimental parameters affecting the fluorescence intensities were carefully studied
and optimized. The relation between fluorescence intensities and drug concentrations were rectilinear over the concentration
range of 0.25–6.0 μg/mL for both drugs with a minimum detectability of 0.065 and 0.045 μg/mL for FNT and RTH, respectively.
The percentage recoveries ±SD were 100.1 ± 0.9, 99.9 ± 0.6 for FNT and RTH respectively. The proposed method was successfully
applied to the determination of both drugs in their commercial dosage forms. The obtained results were statistically validated
and agreed well with those obtained with reference methods. A suggestion for the reaction pathway with DNS-Cl was postulated. 相似文献
9.
D. S. Tsar’kov E. S. Ryndina M. A. Proskurnin V. M. Shkinev 《Journal of Analytical Chemistry》2011,66(2):166-170
A novel method is proposed for the extraction-thermal lens quantification of cobalt with Nitroso-R-Salt based on the distribution
of the colored complex in a two-phase aqueous system on the basis of poly-ethylene glycol (PEG) and an ammonium sulfate solution followed by its thermal lens detection in the extract. The limit of detection is 0.3 μM
(20 ng/mL); the lower limit of the analytical range is 0.7 μM (40 ng/mL); the relative standard deviation for the concentrations
1–50 μM makes 1–3% (n = 6, P = 0.95). In the determination of cobalt by spectrophotometry under the same conditions, the detection limit is 10 μM (0.6
μg/mL) and the lower limit of the analytical range is 40 μM (2.5 μg/mL). The precision of thermal lens measurements in PEG
solutions is higher in comparison to that in aqueous ones because of the weaker interference of convection in aqueous solutions
of PEG. 相似文献
10.
A cheap and simple colorimetric assay based on the reaction with sodium 8-aminoquinoline-5-azobenzene-4′-sulfonate (SPAQ) is applied to the determination of copper in urine and water samples. The proposed technique employs a light emitting diode
(LED) as a light source and a cheap common light dependent resistor (LDR) as a detector. This device functions on the basis of the level of light received by photoresistor (LDR), which is connected
to a digit multimeter yielding resistance readings increasing with the increase in light absorption by sample solution. Experimental
variables affecting the complex formation were optimized applying the Taguchi method. Under the optimum conditions, calibration
plot was linear in the analyte concentration range of 0.1–2 μg/mL. The stoichiometry of metal/ligand ratio, the stability
constant, and molar absorptivity (ɛ) of Cu(II)-SPAQ complex were also found. The relative standard deviation for five replicate
determinations of 1 μg/mL Cu(II) was 3.64% and the corresponding limit of detection was 35 μg/L. 相似文献
11.
Two highly sensitive spectrophotometric methods have been developed for the determination of olanzapine (OLP) in pharmaceuticals using cerium(IV) and iron(II) complexes of 1,10-phenanthroline and 2,2′-bipyridyl as reagents. The methods
are based on the oxidation of OLP in acidic medium by a known excess of cerium(IV) followed by the determination of the unreacted
oxidant by reacting with either ferroin and measuring the absorbance at 510 nm (method A) or iron(II)-2,2′-bipyridyl complex
and measuring the absorbance at 525 nm (method B). The amount of cerium(IV) reacted corresponds to the amount of OLP. In both
the methods, the absorbance is found to increase linearly with OLP concentration as shown by the correlation coefficient (r) of 0.9980 and 0.9958 for method A and method B, respectively. The calibration graphs are linear over the concentration range
of 0.2–2.0 μg/mL in both the methods. The calculated molar absorptivity values are 1.00 × 106 and 7.03 × 105 L/mol cm, for method A and method B. The LOD and LOQ values for method A are calculated to be 0.04 and 0.13 μg/mL and the
values are 0.07 and 0.22 μg/mL for method B, respectively. The methods were validated as per the current ICH guidelines. Both
the methods gave similar results in terms of accuracy and precision. The RSD was less than 3% and the accuracy, obtained from
recovery experiments, was 98.76–101.4%. The methods developed were applied to the determination of OLP in tablets and results
agreed well with the label claim. 相似文献
12.
S. A. Popov Yu. A. Chumichkina E. N. Shapovalova S. G. Dmitrienko Yu. A. Zolotov 《Journal of Analytical Chemistry》2011,66(1):6-10
The potency of molecularly imprinted polymers (MIP) for 2,4-dichlorophenoxyacetic acid (2,4-D) in the dynamic sorption preconcentration (solid phase extraction) of 2,4-D and three other structurally related species
(2,4-dichlorophenol, 2-chlorophenol, and dikamba) from aqueous solutions is assessed. The optimal conditions for preconcentration
are found: 0.01 M HCl, 25–100 mL of solution, flow rate of solution 0.7 mL/min, column (15 × 2.7 mL), and sorbent weight 0.04
g. The analytes are desorbed with 1 mL of methanol and detected in the eluate by reversed-phase HPLC with spectrophotometric
detection at 225 nm. The detection limit for 2,4-D makes 0.4 μg/mL without preconcentration and 0.01 μg/mL with preconcentration
from a volume of 100 mL. The procedure is applied to the analysis of model mixtures based on fresh river water. 相似文献
13.
Two new polyether antibiotics 3, 5 together with three known ones 1, 2, 4 were isolated from Streptomyces hygroscopicus XM201. Based on the unambiguous NMR data assignments, their structures were determined to be 30-acetyl nigericin (1), 1-O-methyl-30-acetyl nigericin (2), 1,29-O-dimethyl-30-acetyl nigericin (3), nigericin (4), and 29-O-methyl abierixin (5), respectively. The antibacterial activities of the nigericin derivatives 1–4 were studied. Compounds 1 and 4 showed strong activities against Staphylococcus aureus ATCC25923 and Bacillus cereus 1126 with MIC of 0.25 μg/mL and 0.125 μg/mL, respectively. No inhibitory activities were observed against Escherichia coli CMCC44103 at a concentration of 25 μg/mL. Only 1 and 4 showed distinguished effects on the protoplast regeneration clones of B. cereus 1126 and E. coli CMCC44103 at a concentration of 1 μg/mL.
Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 285–288, May–June, 2009. 相似文献
14.
M. A. Naushad M. Aqil F. J. Ahmad A. Ali M. S. Faisal M. Rizwan S. Faiyaz 《Journal of Analytical Chemistry》2008,63(10):965-970
A simple, economic, selective, precise, and accurate high-performance liquid chromatographic (HPLC) method for the analysis of trimetazidine hydrochloride in both bulk drug and pharmaceutical formulations was developed and
validated in the present study. The mobile phase consisted of water: methanol: triethylamine (75: 25: 0.1 v/v/v), and pH 3.3
was adjusted with orthophosphoric acid. This system was found to give a sharp peak of trimetazidine hydrochloride at a retention
time of 3.375 ± 0.04 min. HPLC analysis of trimetazidine hydrochloride was carried out at a wavelength of 232 nm with a flow
rate of 1.0 mL/min. The linear regression analysis data for the calibration curve showed a good linear relationship with a
regression coefficient of 0.997 in the concentration range of 5–90 μg/mL. The linear regression equation was y = 35362x −
8964.2. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 3.6 and 10.9 μg/mL, respectively. The developed method was employed with a high degree of precision and
accuracy for the analysis of trimetazidine hydrochloride. The developed method was validated for accuracy, precision, robustness,
detection, and quantification limits as per the ICH guidelines. The wide linearity range, accuracy, sensitivity, short retention
time, and composition of the mobile phase indicated that this method is better for the quantification of trimetazidine hydrochloride.
The text was submitted by the authors in English. 相似文献
15.
Simple and sensitive methods for the spectrophotometric determination of iron(III) in food, based on the formation of coloured
complexes of Fe(III) with Chromazurol S (CAS) in the presence of tetradecyltrimethylammonium bromide (TTA) or octadecyltrimethylammonium chloride (ODTA) and Triton X-100 (TX100), have been developed. Optimum pH and the concentrations of CAS, TTA, ODTA, and TX100 ensuring maximum
absorbance have been determined. For the Fe-CAS-TTA-TX100 system the molar absorptivity is 1.12 × 105 L/(mol cm) at 650 nm; for Fe-CAS-ODTA-TX100 it is 1.35 × 105 L/(mol cm) at 659.5 nm. Beer’s law was obeyed for iron concentration in the range 0.08–0.56 μg/mL for the complex Fe-CAS-TTA-TX100
and 0.08–0.64 μg/mL for Fe-CAS-ODTA-TX100. The influence of several interfering ions has been discussed. The stoichiometry
of the complexes was established by applying Job’s method. The more sensitive method, based on the Fe-CAS-ODTA-TX100 system,
has been applied to the determination of iron in cereals. To evaluate the accuracy of the elaborated method, the determined
content of Fe was compared to the declared value as well as to the result obtained by the reference ICP-OES method. 相似文献
16.
Halil İbrahim Ulusoy Ramazan Gürkan Öznur Yılmaz Mehmet Akçay 《Journal of Analytical Chemistry》2012,67(2):131-139
A sensitive and selective method has been developed for the determination of chromium in water samples based on using cloud
point extraction (CPE) preconcentration and determination by flame atomic absorption spectrometry (FAAS). The method is based on the complexation of Cr(III) ions with Brilliant Cresyl Blue (BCB) in the presence of non-ionic surfactant Triton X-114. Under the optimum conditions, the preconcentration of 50 mL of water
sample in the presence of 0.5 g/L Triton X-114 and 1.2 × 10−5 M BCB permitted the detection of 0.42 μg/L chromium(III). The calibration graph was linear in the range of 1.5–70 μg/L, and
the recovery of more than 99% was achieved. The proposed method was used in FAAS determination of Cr(III) in water samples
and certified water samples. In addition, the developed CPE-FAAS method was also used for speciation of the inorganic chromium
species after reduction of Cr(VI) to Cr(III) using a thiosulphate solution of 120 mg/L in the presence of Hg(II) ion as a
stabilizer. 相似文献
17.
H. Y. Wang M. L. Pan Y. L. Oliver Su S. C. Tsai C. H. Kao S. S. Sun W. Y. Lin 《Journal of Analytical Chemistry》2011,66(4):415-420
Carbamazepine is a widely used anti-epileptic drug with narrow therapeutic range. Many methods have been developed for monitoring
the serum drug level. Differential pulse voltammetry (DPV), an electrochemical method advantaged by simple, inexpensive, and relatively short analysis time, has recently been developed
for carbamazepine detection. We used a newly developed DPV method with glassy carbon as a working electrode to determine the
carbamazepine level. The performance of DPV is compared with the widely used fluorescence polarization immunoassay (FPIA) technique in precision, accuracy, linearity and detection limit. The precision, linearity and accuracy of the DPV and FPIA
techniques were comparable at most clinical used levels. The detection limit was 1 μg/mL for the DPV technique and 0.5 μg/mL
for the FPIA technique. The performance of the DPV technique was within the FDA guidelines for bioanalytical methods, which
ensures the clinical applicability of the DPV technique. The DPV technique may have the potential to be a good alternative
for carbamazepine analysis. 相似文献
18.
Two new quinones, 1,4,7-trihydroxy-2-methoxy-6-methylanthracene-9,10-dione (1) and compound 2, were isolated from fructus rhodomyrti of Rhodomyrtus tomentosa (Ari.) Hassk., which was collected from Guangdong Province. The structures were elucidated by 1D, 2D NMR, and HR-EI-MS spectroscopy
methods. The cytotoxic activities of two compounds in vitro were tested. Compound 1 showed cytotoxicity against KB and KBv200 cell lines with IC50 of 17.1 and 19.5 )μg/mL, and compound 2 with IC50 of 18.1 and 25.4 )μg/mL, respectively. 相似文献
19.
Ragaa El‐Sheikh Monir Zaky Faten Zahran Mohamed Alaa Sayed Amin Ayman Abou El‐Fetouh Gouda 《中国化学会会志》2006,53(4):831-838
Three simple, sensitive and accurate spectrophotometric methods have been developed for the determination of dextromethorphan hydrobromide (DEX) and ketamine hydrochloride (KET) in dosage forms. These methods are based on the formation of ion‐pair complexes with bromocresol green (BCG), bromocresol purple (BCP), and bromophenol blue (BPB) in acidic medium. The coloured ion‐pair products are measured at 419, 409 and 417 nm for DEX and at 417, 408 and 416 nm for KET using BCG, BCP and BPB, respectively. Beer's law was obeyed in the range of 2.0–22 μg mL?1 for DEX and 2.0–16 μg mL?1 for KET. The composition of the ion‐pair was established by continuous variation and molar ratio methods. The proposed methods were applied successfully for the determination of DEX and KET in dosage forms applying the standard addition technique and compared statistically with the official methods. The molar absorptivity, Sandell sensitivity, detection and quantification limits were also calculated. 相似文献