共查询到8条相似文献,搜索用时 15 毫秒
1.
Tehseen Aman Shamma Firdous Islam Ullah Khan Asrar Ahmad Kazi 《Mikrochimica acta》2001,137(3-4):121-126
Phenytoin sodium reacts with o-nitrobenzoic acid in alkaline media after heating for 10 minutes at 70 °C, to give a red coloured
complex having maximum absorbance at 510 nm. The reaction is selective for phenytoin sodium with 0.01 mg/10 mL as visual limit
of quantitation and provides a basis for a new spectrophotometric determination. The colour reaction obeys Beer’s law from
0.01 mg to 3 mg/10 mL of phenytoin sodium and the relative standard deviation is 0.29%. The quantitative assessment of tolerable
amounts of other drugs is also studied.
Received May 2, 2000. Revision May 11, 2001. 相似文献
2.
Four spectrophotometric methods are described and applied to resolve binary mixtures of the corticosteroid hydrocortisone
and the antibacterial polypeptide Zn-Bacitracin. The simultaneous determination of the two compounds was accomplished by means
of derivative methods, which were satisfactory used to determine synthetic mixtures of these compounds in different ratios
and in pharmaceutical preparations (only for hydrocortisone). Direct absorption spectra of compounds were used to optimise
the spectral data set performs the calibration by PLS-1, PLS-2 and PCR algorithms. These calibration models were evaluated
through internal validation (prediction of compounds in its own designed training set of calibration), cross-validation (obtaining
statistical parameters that show the efficiency for a calibration fit model) and external validation over synthetic and pharmaceutical
mixtures. The four described procedures do not require any separation step. Precision studies were achieved over two series
of ten standards for each compound showing no significant differences at 95% confidence level in the two spectrophotometric
methods. The results found in commercial products were compared with those obtained by means of MEKC method and similar values
were found.
Correspondence: Department of Analytical Chemistry and Food Technology, Universidad de Castilla-La Mancha, 13071 Ciudad Real,
Spain. e-mail: JoseMaria.Lemus@uclm.es
Received January 25, 2002; accepted October 22, 2002 相似文献
3.
《Analytical letters》2012,45(11):1963-1974
Abstract In this study, two new spectrophotometric methods were used for the simultaneous determination of cilazapril and hydrochlorothiazide in their binary mixture. In the first method, derivative spectrophotometry, dA/dδ values were measured at 242.8 nm and 282.8 nm for cilazapril and hydrochlorothiazide, respectively, in the first derivative spectra of their combination. The relative standard deviation of the method was found to be 0.77% for cilazapril and 0.24% for hydrochlorothiazide. In the second, the absorbancy ratio method, the quantification of cilazapril and hydrochlorothiazide was performed by using the absorbances read at 210.4 nm. 250.2 nm and 270.6 nm in the zero-order spectra of their mixture; relative standard deviations of the method were found to be 1.26 % and 0.81 % for cilazapril and hydrochlorothiazide, respectively. These two methods have been successfully applied to a tablet containing these drugs. 相似文献
4.
《Analytical letters》2012,45(14):2708-2720
Abstract A simple, sensitive, and direct spectrophotometric method has been developed for the assay of sparfloxacin in bulk and pharmaceutical preparations. The proposed method is based on the formation of ternary complex between an investigated drug, palladium(II) ion and eosin in the presence of methylcellulose as surfactant and acetate buffer of pH 4.2. Spectrophotometrically, under the optimum conditions, the ternary complex showed absorption maximum at 550 nm, with apparent molar absorptivity of 2.69×104 l mol?1 cm?1, Sandell's sensitivity of 0.01458 µg ml?1 and linearity in the concentration range 1.6–16 µg ml?1. The composition of the ternary complex was studied by Job's method of continuous variation and the result indicated that the molar ratio of SPFX: Pd: eosin is 1∶1∶1. The optimum reaction conditions and other analytical parameters are evaluated. The proposed method was successfully applied for the determination of SPFX in its pharmaceutical product with mean percentage recoveries of 99.71%. The observed data has been subjected to statistical analysis, which revealed high accuracy and precision. 相似文献
5.
《Analytical letters》2012,45(5):859-866
Abstract The use of partial least - squares multivariate spectrophotometric calibration for the simultaneous determination of theobromine and caffeine in cocoa is presented. The results show that these components in a molar ratio of about 6 : 1 in cocoa have been determined simultaneously with standard deviations of about 0.05 and 0.02 for theobromine and caffeine, respectively. 相似文献
6.
7.
Masoud Shariati‐Rad Mohsen Irandoust Tayyebeh Amini Mojtaba Shamsipur 《Journal of Chemometrics》2013,27(3-4):63-69
For simultaneous determination in conditions with spectral overlap and variation of matrix effects, coupling of the generalized standard addition method (GSAM) with the multivariate nonlinear method of radial basis function–partial least squares (RBF–PLS) was proposed. The nonlinearity caused by the GSAM used to correct matrix effects was studied, and principal component analysis was proposed for identifying it. In the method introduced, the whole sensor range can be used without the collinearity problem encountered in the application of GSAM with classical least squares (CLS), and calibration can be made for each analyte, separately. The introduced method was applied to determine amlodipine and atorvastatin in urine samples. The mean of the percent recoveries was between 95 and 101.12. The percent relative standard deviation values of the method were in most cases below 5%. The results of GSAM–RBF–PLS were compared with those obtained by GSAM–CLS and GSAM–PLS. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
8.
Elena Chekmeneva José Manuel Díaz‐Cruz Cristina Ariño Miquel Esteban 《Electroanalysis》2010,22(2):177-184
The complexation of the natural antioxidants α‐lipoic acid (ALA) and its reduced form dihydrolipoic acid (DHLA) with Hg2+ was investigated by a recently proposed differential pulse voltammetric (DPV) method using the rotating Au‐disk electrode. Complexation processes are proposed from the multivariate curve resolution by alternating least squares (MCR‐ALS) analysis of DPV titration data. Main complexes were both 1 : 1 Hg : ALA and Hg : DHLA, although the formation of 1 : 2 complexes can be also deduced. ALA and DHLA show different Hg2+‐binding patterns at different pH. Voltammetric findings are completed with the data obtained by electrospray ionization mass‐spectrometry (ESI‐MS), especially in negative mode. 相似文献