Pre-column conversion of ammonia and a number of aliphatic amines into phenylthiourea or its derivatives by reaction with phenyl isothiocyanate, followed by HPLC, has been used for their determination in environmental waters. Optimum conversion was found when the reaction was carried out in sodium hydrogencarbonate– carbonate medium at 40 °C for 15 min. Well separated peaks were obtained on a C...

On the basis of the integrable Kaup-Boussinesq version of the shallow water equations, an analytical theory of undular bores is constructed. The problem of the decay of an initial discontinuity is considered.

We have determined routinely administered benzodiazepines and some of their metabolites in clinical samples by using on-line column switching for sample clean-up and reversed-phase high-pressure liquid chromatography (HPLC). The plasma sample is directly injected onto a cyanopropyl (CN) pre-column, washed with buffer, and eluted onto an analytical column (C18, octadecylsilane). Analytical recov...

Vietnam's sea is assessed to be very diverse and rich in seaweed species. It about 1000 different species of seaweed, which more than 800 have been identified, classify into genus, families, classes, phylums, continuously updated from the 1950s present. Previous studies by Vietnamese international scientists shown that lipids contain many valuable active ingredients such as acids C20: 4n-6 (AA)...

A HPLC method for simultaneous determination of diclofenac sodium and papaverine hydrochloride in tablets was developed and validated. The determination was performed with a Zorbax SB-C18 column, mobile phase: methanol-water (60:40, v/v), flow rate: 1 mL min(-1) and UV detection at 278 nm.

A simple, sensitive, rapid, precise and economical reverse phase HPLC method has been developed for the estimation of valsartan from pharmaceutical dosage forms. The was carried out using Chromatographic conditions were established by employing a C18 analytical phenomenal (Kinetex) column (5micron -C18, 250x4.6mm) with mobile phosphate buffer (PH 3.5) acetonitrile in 60:40 ratio. sample injecte...

a validated hplc method was developed to determine doxorubicin concentration in a small volume of rat plasma (60 µl) with convenient fluorescence detection. sample preparation includes a simple one-step liquid-liquid extraction using minimum amount of organic solvent, with extraction recoveries more than 95%. the analysis was accomplished using perfectsil c18 column maintained at 35 °c and a mo...

In this article, the diocotron modes developing in a coaxial diode and resonant magnetron forming six-vane A6 relativistic both fed by split cathode are studied Particle-in-Cell simulations. The is novel type of which sustains column longitudinally oscillating electrons (smooth bore) or over non-emitting axial conductor. connection between longitudinal oscillatory dynamics mode development, as ...

This study involves the incorporation of a commercially available Phenomenex Onyx C18 monolith column into the separation and detection of oxidative DNA damage. It includes thorough investigation of monolith performance and a comparison of the performance of monolith columns with a commercially available packed Restek reverse phase Ultra C18 column for the separation of DNA bases and nucleoside...