A sensitive and specific HPLC method has been developed for the assay of amlodipine in human plasma. The assay involves derivatization with 4-chloro-7-nitrobenzofurazan (NBD-Cl), solid-phase extraction on a silica column and isocratic reversed-phase chromatography with fluorescence detection. Nortriptyline hydrochloride was used as an internal standard. The assay was linear over the concentrati...

An acid extract of pedal ganglia of the mollusc Mytilus edulis was fractionated by high-pressure liquid chromatography with a reverse-phase column. Peak fractions with retention times of those of [Met]- and [Leu]enkephalin were subjected to binding assays in both invertebrate and vertebrate tissues. The results showed that these fractions have the same binding activities as authentic enkephalin...

A methodology based on coupling isocratic high-performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS) with optimized collision/reaction cell conditions has been developed for the simultaneous analysis of organic and inorganic selenium species in natural water samples. Selenium concentrations found in total and speciation analysis of a number of water ...

An alternative methodology for analysis of acetaminophen (Ace), phenylephrine (Phe) and carbinoxamine (Car) in tablets by ion-pair reversed phase high performance liquid chromatography was validated. The pharmaceutical preparations were analyzed by using a C18 column (5 μm, 300 mm, 3.9 mm) and mobile phase consisting of 60% methanol and 40% potassium monobasic phosphate aqueous solution (62.46 ...

A method using liquid chromatography has been developed and validated for determination of buclizine in pharmaceutical formulations and in release studies. Isocratic chromatography was performed on a C18 column with methanol:water (80:20 v/v, pH 2.6) as mobile phase, at a flow rate of 1.0 mL/min, and UV detection at 230 nm. The method was linear, accurate, precise, sensible and robust. The diss...

A sensitive and reproducible high-performance liquid chromatography-fluorescence method was developed and validated for quantitative determination of indoxyl sulfate in plasma using methyl paraben as an internal standard. The separation was carried out on an OSD-2 C18 Spherisorb column by isocratic elusion with sodium acetate buffer (pH 4.5) and acetonitrile (10:90, v/v) as the mobile phase. Th...

A rapid isocratic high-pressure liquid chromatography procedure for the analysis of ethosuximide, phenobarbitone, phenytoin, and carbamazepine in serum is described. The method employs a single extraction from serum; alumina treatment of this extract eliminates interference from fast-eluting compounds, allowing rapid chromatography. A linear response is obtained for drug concentrations up to th...

Here we describe fast analysis of biomolecules by newly developed pressure-driven liquid chromatography (LC) on a chip with integration of a gradient elution system. We have reported the fabrication of a gradient elution system using a cross-Tesla mixer on a chip with pillar array columns [1]. In this study, we applied the chip to the analysis of biological compounds, and showed that 10 times f...

In this improved method for quantifying 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) in urine, after a multistep extraction of MHPG and internal standard (iso-MHPG) from 3.0 mL of urine, the compounds are separated on a C18 reversed-phase column and quantified by use of an electro-chemical detector. The isocratic chromatographic separation takes about 16 min. The mobile phase is phosphate buf...

An isocratic reversed-phase liquid chromatographic method was developed and validated for the determination of Solifenacin succinate. Chromatographic separation was achieved on a C18 column using an aqueous tetra butyl ammonium hydrogen sulphate (10 mM): acetonitrile (40:60, v/v), with flow rate 0.8 mL/min (UV detection at 254 nm). Linearity was observed in the concentration range of 20-200 μg/...