Fast high-performance liquid chromatographic determination of R(+)[(5,6-dichloro-2,3,9,9a-tetrahydro-3-oxo-9a-propyl-1-H-fluoren-7-yl)oxy]acetic acid in human plasma and urine

A simple and rapid high-performance liquid chromatographic method for the determination of R[(5,6-Dichloro-2,3,9,9a-tetrahydro-3-oxo-9a-propyl-1-H-fluoren-7-yl)oxy]acetic acid (I) in human plasma and urine is described. The method utilizes Bond-Elut® cartridge facilitate the drug extraction. Analysis is performed on a short reversed-phase column with a mobile phase consisting of acetonitrile and phosphate buffer and quantification is carried out by ultraviolet detection with a wave-length set at 340 nm. The method is linear and reproducible for both plasma and urine analyses (0.25–50) μg/mL) with the detection limit of 125 ng/mL of plasma and urine. Plasma and urine concentrations of / at selected time intervals following I.V. administration of single rising doses are presented.     

Extraction-spectrophotometric determination of some antihistaminic agents with fast green FCF

A rapid, simple, precise, accurate and highly sensitive method for the determination of some antihistaminic agents such as dimethindene maleate (DMM), embramine hydrochloride (EMH), isothipendyl hydrochloride (IPH), mebhydrolin napadisylate (MHn), methdilazine hydrochloride (MDH), promethazine hydrochloride (PMH), trimeprazine tartrate (TMT) and triprolidine hydrochloride (TPH) in bulk samples and pharmaceutical preparations is proposed. The method is based on the formation of a chloroform-soluble ion-association complex between the antihistaminic agent and Fast Green FCF at pH 5.0 with an absorption maximum at 620 nm. The composition of antihistaminic agent and Fast Green FCF in each ion-association complex is studied. The relative standard deviation of the proposed method is less than 1.3%, the percent recovery is 99.4–100.2% and the results are not significantly different from the standard methods at the 95% confidence level.     

Fast GC analysis with a 50 microm ID column: theory, practical aspects, and application to a highly complex sample

This research focuses on the minimization of GC analysis times through the use of a 5 m x 0.05 mm ID x 0.05 microm (film thickness) column. Experimental minimum plate height (Hmin) and optimum linear velocity values were derived from standard compound applications, under various analytical conditions, and then related to classical chromatographic theory. Deviations from the latter are measured and discussed. Practical aspects linked to the use of such capillaries, such as column sample capacity and detector acquisition rates, are also considered. Furthermore, a fast, and what can be considered a very fast method, were applied to the separation of a fuel sample. Coefficients of variation of elution times and relative peak areas were calculated in the very fast application. All analytical results are compared with those obtained by conventional 0.25 mm ID column applications.     

Theory of fast capillary gas chromatography part. 2: Speed of analysis

Using hold-up time as a measure of the speed of analysis with a given column efficiency, a theory of pneumatic optimization of a column in the fast high pressure drop isothermal and temperature programmed GC is developed. Expression for the hold-up time as a function of column efficiency, carrier gas velocity and film thickness is derived. Also found are the expressions for the minimum hold-up time and optimum gas velocity in a speed-optimized column. These quantities are compared with their counterparts in the efficiency-optimized column.     

Liquid chromatography/fast-atom-bombardement mass spectrometry of nonionic detergents

Summary Microcolumn liquid chromatography (LC) combined with fast-atom-bombardment mass spectrometry (FABMS) was applied to the analysis of nonionic detergents. The porous silver filter attached to the top of the capillary fused-silica tubing worked as the interface for coupling of micro LC and FABMS.     

冠醚稀土络合物的快原子轰击质谱

本文报道十余个冠醚稀土络合物的快原子轰击质谱(FABMS)。通过分析FABMS的特征及亚稳离子分解讨论了溶液中的反应和络合性质。     

快速气相色谱法测定食品中的常见防腐剂

摘要：建立了一种分离测定食品中6种常见防腐剂(山梨酸，苯甲酸，对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯、对羟基苯甲酸丁酯)的简单、准确的快速气相色谱方法，采用长10m，内径100μm的HP-5熔融石英毛细管柱，在快速程序升温条件下，6种常见防腐剂的分析时间为1．3min。各组分平均回收率(n=3)为96．45％；检出限为1．2～10μg／mL；线性相关系数大于0．994。该方法已用于实际食品中防腐剂的检测。     

Feasibility study: fast liquid chromatography–mass spectrometry for the quantification of aspartic acid in an aspartate drug

We have studied the feasibility of fast high-performance liquid chromatography coupled to electrospray ionization mass spectrometry in the selected ion monitoring mode for the quantitative determination of aspartic acid in an aspartate drug. Internal standardization was required, but mass spectrometric detection allowed for very short retention times of approximately 0.5 min for the analyte and the internal standard without chromatographic separation. The analytical system was found stable, as demonstrated by multiple injections giving a coefficient of variation of 4% for the peak area ratio of aspartic acid and glutamic acid. Calibrations were linear between 0.5 ng and 150 ng aspartic acid injected, with accuracies between 99.8% and 102% found for the back-calculated amounts. Investigation of several drug batches gave reasonable results. Therefore, the method appeared feasible for the determination of aspartic acid in an aspartate drug from 0.3 wt% to 100 wt% aspartic acid.Abbreviations CV coefficient of variation - ESI electrospray ionization - HPLC high-performance liquid chromatography - HSGC headspace gas chromatography - KaFi Karl Fischer titration - MS mass spectrometry - MSD mass-selective detector - % m/m percentage by weight - PAR peak area ratio - r² coefficient of determination - RP reversed-phase - SIM selected ion monitoringThis work was originally presented as a poster at the Conference of the German Society for Mass Spectrometry, 9–12 March 2003, in Münster, Germany     

Geometry Optimization of Ba2+(H2O)n Clusters Using a Fast Hybrid Global Optimization Algorithm

A global optimization called fast hybrid global optimization algorithm was proposed based on genetic algorithm, fast simulated algorithm and conjugated gradient algorithm. We employ it to search the global minimum energy structures of Ba²⁺(H₂O)_n clusters for n = 1–30 within the TIP4P model. The results show that Ba²⁺(H₂O)_n clusters have the n+0 structure while n = 1–8. When n is in the range 9 ≤ n ≤ 18, the number of water molecules in the first shell around the barium ion is 8 and the other water molecules arrange in the outer shell. In the global minimum structure of Ba²⁺(H₂O)₁₉, the number of the first shell water molecules adds up to 9, and the value is kept until n = 30. According to the computational results, a conclusion that hydration numbers for Ba²⁺ is 9 can be drawn, which is in agreement with the result by a Monte Carlo simulation.     

Evaluation of thin layer chromatography—Fast atom bombardment mass spectrometry: Application to the determination of midazolam intoxication by use of 3-glycidoxypropyl-treated thin layer chromatographic plates

Summary The effectiveness of 3-glycidoxypropyl-treated thin layer chromatographic plates in the determination of midazolam intoxication has been studied by thin layer chromatography/fast atom bombardment mass spectrometry. Silica plates treated with 3-glycidoxypropyldimethylethoxysilane were used for the measurement of their physical composition and for chemical analysis. From elemental carbon analysis data, the maximum number of bonded 3-glycidoxypropyl surface groups per gram was calculated to be 0.417×10²¹. Midazolam in human serum from patients suffering from intoxication could be separated on a 3-glycidoxypropyl-treated thin layer chromatographic plate with chloroform as eluent. After applying the technique of diffused spot condensation on the 3-glycidoxypropyl-treated thin layer chromatographic plate, the established thin layer chromatography/fast atom bombardment mass spectrometry method was used for the identification of midazolam intoxication, and improved the detection limit for midazolam in the serum of an intoxication patient by 30 times.