Determination of oxalate in pharmaceutical matrices by indirect photometric chromatography

An indirect photometric ion chromatography method is developed for the quantitation of oxalate in typical pharmaceutical matrices. The column/mobile phase conditions used represent a trade off between resolving power and sensitivity and results in an assay with a total analysis time of less than 9 minutes. Method response is linear between concentrations of 10 to 80 ppm oxalate. The limit of quantitation is roughly 5 ppm. Precision in the range of 30 to 80 ppm is better than 1.0% RSD of replicate injections, and the accuracy in a variety of matrices is 100 +/- 2%. The method is quite rugged and meets rigorous suitability requirements even after 500 injections. Although the assay can be used to quantitate citrate as well, the retention time is relatively long (20 minutes) and sensitivity is limited due to the broadness of the peak.     

Application of micellar electrokinetic chromatography to pharmaceutical analysis

Electrokinetic chromatography is a new type of analytical separation method which belongs to the group of high performance capillary electrophoretic techniques but whose separation principle is based on that of chromatography. The solute distributes itself between a carrier and the surrounding medium. The carrier, which corresponds to the stationary phase in conventional chromatography, can be transported by electrophoresis with a different velocity from the surrounding medium. The separation is achieved by the differential solute distribution and the differential migration of the carrier. The charged molecules or charged molecular aggregates are employed as the carrier. Various kinds of carriers are available for electrokinetic chromatography along with different partition mechanisms. Among them, micellar electrokinetic chromatography, which employs an ionic micelle as a carrier, has become the most popular method because of its unique and attractive characteristics as well as the separating capability of electrically neutral or nonionic solutes in comparison with capillary zone electrophoresis. The present paper describes the principle, separation characteristics and its application to the analysis of pharmaceuticals.     

Liquid chromatography of cyclodextrins with indirect photometric detection of phenolphthalein inclusion complexes

Summary - and -cyclodextrin (CD) separated by liquid chromatography have been indirectly detected by depression of the background absorbance at a visible wavelength by means of inclusion complexation with phenolphthalein. The background signal was generated by phenolphthalein in an alkaline medium. Octadecyl-bonded poly(vinylalcohol) packings were employed as the stationary phase, which allowed the use of alkaline mobile phases, and eliminated post column mixing of reagents. The detection limits for - and -CD were 0.1–0.5 M at a signal to noise ratio of 3. -CD could not be measured by the present detection principle.     

Optimization of single-column anion chromatography with indirect ultraviolet photometric and fluorimetric detection

Optimization of single-column anion chromatography with indirect photometric and indirect fluorimetric detection is described. A simplex algorithm is used for signal maximization with eluent concentration, pH and flow rates as dependent variables. Absolute detection limits obtained for chloride, nitrite, nitrate and sulphate by indirect photometric detection were 1.0, 1.2, 1.4, and 2.0 ng, respectively. The use of single-beam indirect fluorimetric detection of these anions is also demonstrated. The method was applied to the detection of anions arising from gaseous acids or atmospheric aerosols.     

Application of gradient high-performance liquid chromatography to the analysis of some multicomponent pharmaceutical preparations

Procedures were developed for determining streptocide and norsulfazole in the Ingalipt aerosol; dexpanthenol and nipagin in the Dekspantenol aerosol; and oxymetazoline and benzalkonium chloride in a nasal spray by reversed-phase high-performance liquid chromatography (HPLC) in the gradient elution mode using the CH₃CN-0.025 M aqueous solution mixture of KH₂PO₄ (pH 3.0) and UV detection. The developed procedures are comparable in accuracy and precision to chromatographic procedures recommended by regulatory documents; however, they ensure the simultaneous determination of all components of the pharmaceutical preparations and are more rapid and less laborious.     

Sensitive, indirect photometric detector for high-performance liquid chromatography using a light-emitting diode

A low-noise detector for indirect photometric detection has been constructed using a highly stable source--a light-emitting diode (LED). Use of the detector is demonstrated for reversed-phase liquid chromatography by adding methylene blue to the mobile phase to make a background signal. The indirect determination of alcohols by their effect on methylene blue concentration distribution is demonstrated, and an investigation is made into the conditions for high sensitivity. Because the source exhibits low noise, the detection limits for alcohols are as low as more complex and expensive detection methods, despite the lower radiant power of the LED. Detection limits for nine alcohols are below micrograms injected amounts.     

The application of chromatography to the analysis of pharmaceutical creams

Summary The application of GLC, HPLC and TLC to the analysis of pharmaceutical creams is discussed with special attention to sample clean-up. The results of the determination of hydrocortisone acetate, salicylic acid, benzoic acid, diethyl stilbestrol, chloramphenicol, diphenhydramine HCl, tretinoin and some cream base components by reversed phase HPLC are given.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Determination of alcohols in alcoholic beverages by micro high-performance liquid chromatography with indirect photometric detection

Aliphatic alcohols in alcoholic beverages were determined by micro high-performance liquid chromatography with indirect photometric detection. Theophylline was added to the mobile phase as the visualization agent. Ethanol, propanols and butanols could be determined by this method.     

Microcolumn ion chromatography of inorganic anions using bovine serum albumin stationary phase with indirect photometric detection

Summary Microcolumn ion chromatography of inorganic anions has been studied using bovine serum albumin immobilized on silica gel as a stationary phase. Several mobile phase solutions were examined, involving sodium iodide, potassium hydrogen phthalate, 2,6-anthraquinone disulfonate (2,6-AQDS) and sodium salicylate. 2,6-AQDS achieved better separation of the analytes tested. Chloride, nitrate, iodide, thiocyanate and sulphate could be separated within 8 min. Detection limits were in the range of 0.9–2.9 M, corresponding to mass detection limits of 0.18–0.59 pmol. The system was applied to the determination of inorganic anions in environmental water and biological samples.     

纳米材料在光度分析中的应用进展

本文在对纳米材料的性质简要介绍的基础上,综述了近年来纳米金、纳米银以及纳米氧化铁等纳米材料在光度分析中的应用进展,并对其在生命分析化学中的典型应用进行了较为详细的介绍。展望了今后纳米材料在该领域的主要发展方向。共收录文献104篇。     

Phenylalanine as eluent for indirect photometric detection

Summary In this paper the use of phenylalanine as eluent for indirect photometric chromatography is reported. The effects of the mobile phase pH, phenylalanine concentration etc. on the eluent strength and the sensitivity of detection are discussed. Using 3 mM aqueous solution of phenylalanine at pH 3.0 containing 1% methanol as the mobile phase, a mixture of alkali metals was separated and sodium ion concentration in water was determined on a low-capacity cation-exchange column.     

High-speed ion-pair partition chromatography in pharmaceutical analysis.

Ion-pair chromatography offers attractive possibilities in pharmaceutical analysis. The specificity of the separation systems can be varied over a wide range by appropriate selection of the stationary phase. The choice of a suitable counter-ion can also drastically improve the detection limit, permitting the determination of drug substances in low dosage and possibly of by-products or breakdown products. Ion-pair chromatography of tropane and ergot alkaloids has been investigated using picrate as counter-ion. Alumina, Kieselguhr and various grades of silica gel have been tested as supports. Partition properties studied in a batch procedure have been compared with the actual chromatographic conditions. Columns (10 cm) filled with silical gel (particle size, 5 mum; pore size, 1000 A) show the best performance in the separation of hyoscyamine, scopolamine and ergotamine as picrate ion-pairs. Close control of pH and temperature is essential for reproducible separations. Improvements in detection limits between 100 and 300 times have been observed with these systems. Ion-pair extractions of these alkaloids from dosage forms can be used for sample preparation prior to injection on the the column. This provides an added degree of selectivity and sensitivity.     

高效液相色谱-间接光度检测法测定己内酰胺酸团中的正己烷含量

采用在流动相中添加有紫外吸收的本底试剂的方法,利用高效液相色谱-间接光度检测法直接测定己内酰胺酸团中无紫外吸收的正己烷含量。考察了流动相组成、本底试剂的种类和浓度、波长梯度等对测定的影响。确定的高效液相色谱条件: 色谱柱为Agilent HC-C18柱(250 mm×4.6 mm, 5 μm),流动相为含1.17 mmol/L 1,5-萘二磺酸(本底试剂)的甲醇-水(85:15, v/v)溶液,柱温为35 ℃,流速为1.0 mL/min,并采用设定波长梯度的方法调整系统峰和被测峰的相对大小。该分析方法的线性范围为0.5～20 mg/kg,相关系数为0.99993,相对标准偏差为2.53%,检出限为0.03 mg/kg,加标回收率为98.45%～102.3%。方法简单,选择性好,灵敏度高,抗干扰强,可快速准确地测定实际样品中的正己烷。