abstract        background and objective: measurement of amino acids is an important tool for metabolic studies and evaluation of patients’ clinical condition. the aim of this study was to analyze the plasma amino acids using reverse phase high performance liquid chromatography techniques (rp-hplc) with pre-column derivatization by o-phthalaldehyde (opa) in combination with 3- mercaptopropionic...

glutathione (gsh) is one of the most important antioxidants that plays an essential role in detoxification of reactive oxygen species (ros) which oxidizes to glutathione disulfide (gssg). paraquat (pq), awidely used herbicide, causes pulmonary injury with the productionof ros. excessive ros accumulation as a consequence of pq exposure are frequently targeted by gsh thereby oxidative stress lead...

A convenient method for the separation of molecular species of complex lipids such as sphingomyelin and ceramide by argentation high performance liquid chromatography (HPLC) is described for the first time. Molecular species separation of these complex lipids was achieved for quantitative analysis and preparative work by the combined use of argentation and reversed-phase HPLC.-Smith, M., P. Mon...

Ion-exclusion high-pressure liquid chromatography (HPLC) was used to measure poly-beta-hydroxybutyrate (PHB) in Rhizobium japonicum bacteroids. The products in the acid digest of PHB-containing material were fractionated by HPLC on Aminex HPX-87H ion-exclusion resin for organic acid analysis. Crotonic acid formed from PHB during acid digestion was detected by its intense absorbance at 210 nm. T...

A simple method using HPLC and LC-MS/MS was developed for the determination of ultra-high-intensity sweetener, advantame, in processed foods. Advantame was extracted by dialysis, and cleaned up on a Sep-Pak Plus C18 cartridge, then determined by HPLC and LC-MS/MS. The recoveries from 5 kinds of processed foods fortified at the levels of 0.001 g/kg and 0.01 g/kg were 64.1-89.9% (RSD 0.9-6.9%) by...

Clomipramine is a tricyclic antidepressant. Different methods for determination of clomipramine hydrochloride in plasma have been described. Most of these procedures favor the use of acidic back-extraction in extraction procedure and HPLC as the analytical technique. In this study, the clomipramine extraction procedure was modified and a direct injection to the column was performed to shorten t...

Nowadays, the fast and sensitive high-performance liquid chromatographic (HPLC) analysis of derivatized amino acids is a good alternative to the ion-exchange chromatography (IEC) method for plasma amino acids. However, several precautions have to be taken in order to obtain reliable data on the concentration of amino acids in physiological fluids. These include the collection, centrifugation, s...

Nowadays, the fast and sensitive high-performance liquid chromatographic I HPLC) analysis of derivatized amino acids is a good alternative to the ion-exchange chromatography (IEC) method for plasma amino acids. However, several precautions have to be taken in order to obtain reliable data on the concentration of amino acids in physiological fluids. These include the collection, centrifugation, ...

A sensitive and rapid method for determination of angiotensin converting enzyme (ACE) inhibitory activity was developed based on a combination of enzymatic reaction followed by high performance liquid chromatography/electrospray-mass spectrometry (HPLC-ESI-MS) determination of its product. The most commonly used substrate hippuryl-histidyl-leucine (HHL) or hippuryl-glycyl-glycine (HGG) hydrolys...