Ultraviolet spectrophotometr

Yarnelle, M. K. West, K. J. Modification of an Ultraviolet Spectrophotometric Determination of the Active Ingredients in APC Tablets, /. Chem. Educ. 1989, 66, 601-602. 

Schack, J.A. and Waxier, S.H., Ultraviolet spectrophotometric method for the determination of theophylline and theobromine in blood and tissues, J. Pharmacol. Exp. Ther., 97,283,1949. 

Bailey, D.N., Evaluation of drug interferences in the ultraviolet spectrophotometric analysis of plasma theophylline, J. Anal. Toxicol., 2,94,1978. 

He et al. [25] described an ultraviolet spectrophotometric method for the quantitative determination of miconazole in liniments. The drug was analyzed at 272 nm, the average recovery was 99.76% and the relative standard deviation was 0.3%. 

Min et al. [23] determined primaquine phosphate, in tablets, by an ultraviolet spectrophotometric method. Sample was treated with 0.01 M hydrochloric acid and the resulting solution (500 pg/mL) was diluted to 50 mL with 0.01 M hydrochloric acid. The absorbance of the solution was measured at 265 nm versus a reagent blank. Beer s law was obeyed from 8 to 20 pg/mL of primaquine phosphate. Recovery was 100.2% (n = 5) and the coefficient of variation was 0.5%. Results were consistent with those obtained by a pharmacopoeial method. 

Dwivedi et al. used a thin-layer chromatographic densitometric and ultraviolet spectrophotometric methods for the simultaneous determination of primaquine and a new antimalarial agent, CDRI compound number 80/53 [68]. The new antimalari-al agent, compound 80/53 is unstable in acidic conditions where it is converted into primaquine. To conduct stability studies of this compound, thin-layer chromatography densitometric and ultraviolet spectrophotometric determination methods were developed. These methods are also suitable of the determination of compound 80/53 or primaquine in bulk and pharmaceutical dosage forms. 

An ultraviolet spectrophotometric analysis is used to assay pseudoephedrine hydrochloride in tablets. A portion of finely powdered tablets equivalent to approximately 30 mg of pseudoephedrine hydrochloride is placed in a distilling flask which is part of a micro-steam distillation apparatus. Sodium chloride, water, and concentrated sodium hydroxide are added. A minimum of 30 ml of distillate is collected in a volumetric flask containing dilute hydrochloric acid. The flask is made to volume with distilled water and the absorbance of the solution is determined at 257 nm in 1 cm cells and compared to a solution of known concentration of NF Pseudoephedrine Hydrochloride Reference Standard.1... 

An ultraviolet spectrophotometric method based on the absorbance of a periodate oxidation product of pseudoephedrine hydrochloride will be the official method of analysis in the USP XX.19,20 A portion of tablets or syrup in water is placed in a separatory funnel. Sodium bicarbonate and sodium metaperiodate are added. After standing for 15 minutes, 1 N HC1 is added. The solution is extracted with hexane. The hexane extract is filtered and its absorbance determined at 242 nm in 1 cm cells. The amount of the oxidation product of pseudoephedrine hydrochloride is determined by comparison of the sample absorbance against the absorbance of a Pseudoephedrine Hydrochloride Reference Standard treated in the same manner. 

An ultraviolet spectrophotometric analysis is used to determine content uniformity of triprolidine hydrochloride in tablet formulations.1 The triprolidine hydrochloride is extracted from finely powdered tablets with dilute hydrochloric acid. The solution is filtered and diluted to a concentration of approximately 10 Jg triprolidine hydrochloride per ml. The absorbance at 290 nm of the extracted triprolidine hydrochloride solution in 1 cm cells is compared against NF Triprolidine Hydrochloride Reference Standard prepared in dilute hydrochloric acid at the 10 pg/ml level. 

The herbicides are extracted from soil samples with methanol. They are chromatographed on microparticulate silica bonded with octadecyltrichlorosilane using a mixture of methanol, water and ammonia as mobile phase and an ultraviolet spectrophotometric detector. 

The photodiode array detector (PDAD) measures absorption of light waves by a sample. This is considered the most powerful of the ultraviolet spectrophotometric detectors. The optical system focuses light from a deuterium source through the sample flow cell onto several photodiodes. These act as capacitators by holding a fixed amount of charge. When light strikes the photodiodes, they discharge a certain amount of current. 

B27. Broughton, P. M. G., A rapid ultraviolet spectrophotometric method for the detection, estimation and identification of barbiturates in biological material. Biochem. J. 63, 207-215 (1956). 

Huang and Guan have reported an ultraviolet spectrophotometric and coefficient-multiplied method for the determination of procaine hydrochloride in compounded zinc sulfate eye drops [36]. 3 mL of sample was shaken with 1.5 mL of ethyl ether and water, and after removal of the organic phase, water was added to achieve a final volume of 50 mL. The absorbance of this solution was measured at 291 and 344.5 nm. The recovery (n = 6) for procaine was found to be 99.9%, with a relative standard deviation equal to 0.44%. 

Ultraviolet spectrophotometric detection can be carried out at wavelengths in the range 220-254 nm (517, 518, 520, 524, 525, 526). Fluorometric detection, which is particularly suitable for azaperol and carazolol, confers the advantages of selectivity and sensitivity. This mode of detection has been employed for the determination of carazolol residues in serum and plasma, using excitation and emission wavelengths at 330 and 360 nm, respectively (522). Fluorometric detection has also been applied to monitor carazolol and azaperol residues in swine kidney with excitation and emission wavelengths of 246 and 351 nm, respectively (524). 

Bywater andWoRSFOLD (14). At 0° C, the equilibrium concentration of styrene was expected to be about 10 7 mole/liter which is too low to be determined by conventional analytical techniques. The system was. therefore, investigated in the temperature range of 100—150° C, where the equilibrium concentrations were expected to rise to 10 4—103 mole/liter. For these ultraviolet spectrophotometric techniques are applicable. This temperature range is well above that normally considered... 

Atkinson, R.G., Schroder, R., Hallett, I.C., Cohen, D., and MacRae, E.A. 2002. Overexpression of polygalacturonase in transgenic apple trees leads to a range of novel phenotypes involving changes in cell adhesion. Plant Physiol. 129 122-133. Bach, E. and Schollmeyer, E. 1992. An ultraviolet-spectrophotometric method with 2-cyano-acetamide for the determination of the enzymatic degradation of reducing polysaccharides. Anal. Biochem. 203 335-339. 

Direct ultraviolet spectrophotometric methods have been developed to measure naringin in grapefruit (19J and hesperidin in orange juice (20, 21j. While these methods are rapid, they are also nonspeciTTc for flavonoid bitterness. 

Baker and Bottomly [80] developed a multi-residue method for the determination of synthetic pyrethroids in fruit and vegetables. After extraction with hexane-acetone, the pyrethroids are separated from coextractives by a partition process and chromatography on a silica gel column and quantitatively determined by electron-capture gas-liquid chromatography and/or HPLC using an ultraviolet spectrophotometric detector. 

Dean JR. 1989. Ion chromatographic determination of aluminum with ultraviolet spectrophotometric detection. Analyst 114 165-168. 

Pentazocine is identified according to USP XX by use of infrared or ultraviolet spectrophotometric methods. In the first a dispersion in KBr of the dried drug exhibits maxima only at the same wavelengths as a similar preparation of USP Pentazocine Reference Standard. In the ultraviolet method a 1 in 12,500 solution of pentazocine in 0.01 N HC1 exhibits maxima and minima at the same wavelengths as reference standard. Calculated absorbances at 2 8 nm of dried drug and standard do not differ by more than 3.0 % (3). 

Amer et al33 have described a single ultraviolet spectrophotometric method for the determination of phenytoin in pharmaceutical preparations. The mean was 100.9% (six determinations) and the relative standard deviation was 1.2%. 

The following table provides guidance in the selection of mobile phases that are to be used in conjunction with ultraviolet spectrophotometric detection.1-2 The data in this table differ from the data in the other solvent tables in this volume in that the wavelength dependence of absorbance is provided here. Moreover, common mixed mobile phases are considered here. The percentages that are given are on the basis of v/v. 

The following table provides guidance in the selection of mobile phases that are to be used in conjunction with ultraviolet spectrophotometric detection.1... 

The following table is provided to aid in the use of applications of ultraviolet spectrophotometric detectors. The data here are used to evaluate the potential of detection of individual chromophoric moities on analytes.1-3... 

Bosch F, Font G, Manes J. 1987. Ultraviolet spectrophotometric determination of phenols in natural and waste waters with iodine monobromide. Analyst 112 1335-1337. 

El-Yazbi et al. reported an application of a derivative-differential ultraviolet spectrophotometric method for the determination of oxazepam or phenobarbitone in the presence of dipyridamole [24]. Tablets containing the drugs were powdered and dissolved in ethanol. For solutions of oxazepam and dipyridamole, two portions of each were diluted with 0.1 N sulfuric acid and 0.05 M sodium borate, and subjected to differential spectrophotometry with measurements being made at 283, 292, 298 and 282, and 307, and 296 nm. First derivative (ADi)... 

Hu et al. described an ultraviolet spectrophotometric method for the analysis of dipyridamole [25]. A sample (50 mg) of the powdered tablet was dissolved and diluted to 100 mL with 0.01 M hydrochloric acid. A 2 mL portion of the solution was diluted to 100 mL with 0.01 M hydrochloric acid, and the absorbance of the final solution was measured at 283 nm (or at 403 nm for pure dipyridamole). The calibration graph was linear for upto 12 or 60 pg/mL, and suitable for high-content determinations. Results were in good agreement with those obtained by titration with bromate. 

Ultraviolet spectrophotometric analysis of the incorporation or deblocking of the a,a-dimethyl-3,5-dimethoxybenzyloxycarbonyl (Ddz) group in solid phase synthesis has been used by Birr for the analysis of the coupling and deprotection reactions respectively 18 20). Similar spectroscopic properties of the N-protecting groups have been used for the analysis in the solid phase synthesis involving Nps-amino acids 21,22) and Bpoe-amino acids 23). In all these methods the uptake or release of a soluble reagent or byproduct is analyzed. 

Extraction OF Tablets and Capsules Elaborate solvent fractionation schemes are not usually necessary for solid dosage preparations. Most drugs are soluble in methanol and most of the excipients are not therefore the preparation of a simple methanol extract is all that is required. However, if the methanol extract is too concentrated, the spot on the TLC plate will be overloaded and the resultant chromatogram will be useless. Any subsequent ultraviolet spectrophotometric examination of the extract may give specfra which are not on scale. This cannot always be avoided, but the following guide-lines have been found useful. 

The volumes of water used and any dilutions necessary for the ultraviolet examination must be noted in order to give a quantitative estimate of any drug present. Apart from die small amount used for TEC, the bulk of die extract is still available should analysis by gas chromatography or mass spechometry be required. Direct solvent extraction can be applied to the exhacts, and dilutions used for ultraviolet spectrophotometric analysis. This may also be necessary if die syringe is heavily blood-stained. It is important to remember that some of the drugs encountered in syringes are susceptible to alkaline... 

The kinetics of acid catalyzed hydrolysis of ethyl diazoacetate in aqueous solution was studied for the first time by Bredig and Fraenkel [195] in 1905, and the decomposition kinetics of diphenyldiazomethane in aprotic solvents was investigated by Staudinger and Gaule [196] in 1916. Reinvestigations of the ethyl diazoacetate hydrolysis were carried out by Bronsted et al. [197] and Moelwyn-Hughes and Johnson [198], The reaction was followed by gas volumetric measurement of the evolved nitrogen. Ultraviolet spectrophotometric [199] and thermometric [200] methods were applied in more recent studies which were concerned with a variety of different diazo compounds. A review article [201] was published in 1967 even more new material is available today. 

An ultraviolet spectrophotometric method for following reactions of arylsulfonates has been described, but no example of its use with carbohydrate p-toluenesulfonates has yet been reported. 

Ultraviolet spectrophotometric assay of Econazole nitrate 1% solution has been used16 5 ml of sample diluted... 

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