In a previous communication [l] we reported a procedure for the serum determination of midazolam using gas chromatography (GC) with a nitrogenselective detector. GC with nitrogen-selective detection resulted in a selective procedure for the direct determination of midaxolam with a sensitivity of 50 ng/ml. We present, in this paper, a procedure for the direct determination of midazolam and its m...

Gliotoxin is produced by non-ribosomal peptide synthesis and secreted from certain fungi, including Aspergillus fumigatus. It is an epipolythiodioxopiperazine that contains an intact disulphide bridge and is the focus of intense research as a consequence of its negative immunomodulatory properties. Gliotoxin detection is generally enabled by reversed-phase-high-performance liquid chromatography...

Screening methods based on liquid chromatography (HPLC) and capillary electrophoresis (CE) have been developed for the identification and determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, and 3,4-methylenedioxyethylamphetamine in illicit tablets. Diethylpropione, (-)-ephedrine, and 3-amino-1-phenylbutane were also included in the st...

The present investigation reports on the application of a new antioxidant activity assay for the examination of flavonoids. It has been shown that the high-performance liquid chromatography with electrochemical detection (HPLC–ED) measurements allow to obtain additional information about the antioxidative properties of pure compounds by measuring their half-wave potential, the chromatographic p...

A rapid, optimized, and sensitive reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been developed for determination of pentoxifylline in human plasma. The analyte was extracted from the plasma with dichloromethane after addition of 0.2 mL 1 M NaOH. HPLC separation was performed on a C18 analytical column (250 mm × 4 mm i.d.) with acetonitrile–water, 45:55 (v/v), as mo...

The extraction of red beetroot (Beta vulgaris) peel betalains and phenolics was compared with two extraction methods and solvents. The content of total phenolics in the extracts was determined according to a modification of the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE). The profiles of extracts were analysed by high-performance liquid chromatography (HPLC). The compo...

Enantioseparation of amino acid analogues racemic β-amino alcohols has hitherto been thought impossible without prior derivatization. Method developers of chromatographic enantioseparation often face detection challenge due to low ultraviolet (UV) absorbance of these molecules. A new chiral derivatizing reagent, benzimidazole-(S)-naproxen amide, was synthesized to provide UV detectable chiral m...

In this study, quantitative and pattern recognition analyses were developed using HPLC/UV for the quality evaluation of Dipsaci Radix. For quantitative analysis, five major bioactive compounds were assessed. The separation conditions employed for HPLC/UV were optimized using ODS C18 column (250 × 4.6 mm, 5 μm) with a gradient of acetonitrile and water as the mobile phase at a flow rate of 1.0 m...

Recent American Food and Drug Administration guidelines have effectively determined that mixtures of chiral compounds can no longer be brought to the pharmaceuticals marketplace. These guidelines require a means for chiral detection and compound separation. This article describes separation and detection of chiral pharmaceuticals using HPLC with circular dichroism detection. Two over-the-counte...

Endogenous shikimic acid determinations are routinely used to assess the efficacy of glyphosate in plants. Numerous analytical methods exist in the public domain for the detection of shikimic acid, yet the most commonly cited comprise spectrophotometric and high-pressure liquid chromatography (HPLC) methods. This paper compares an HPLC and two spectrophotometric methods (Spec 1 and Spec 2) and ...