High-performance liquid chromatography-mass spectrometry HPLC-MS

MAE in conjunction with high-performance liquid chromatography/mass spectrometry (HPLC/MS) shortened the cleanup procedure and provided satisfactory recoveries (97-102%) for the parent imazethapyr and its two metabolites (hydroxy and glucose conjugate metabolites). 

High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS)... 

The objective of this study is to identify the major metabolites of the drug in question. For this study, the drug in question is incubated with an appropriate in vitro metabolic system to allow the formation of metabolites. Metabolites are then identified using analytical chemical approaches. The in vitro experimental system of choice is human hepatocytes, with high-performance liquid chromatography/mass spectrometry (HPLC/MS) or tandem mass spectrometry (HPLC/MS/MS) as the most convenient analytical tool to identify the metabolites. 

A method that uses high performance liquid chromatography/ mass spectrometry (HPLC/MS) for the analysis of chlorinated phenoxyacid herbicides is described. During method development different techniques were used to increase both the sensitivity and the specificity of thermospray HPLC/MS for chlorinated acid herbicides. These included the operation of the instrument in the negative chemical ionization (NCI) mode initiated by discharge and the use of a wire-repeller in the ion source for efficient extraction of positive ions. Single quadrupole repeller-induced and multiple quadrupole collision activated dissociation (CAD) experiments were also performed to increase the structural information of the mass spectra. 

Many approaches have been used to form ions, both in high-vacuum and near-atmospheric pressure conditions. Electron ionization (El) and chemical ionization (Cl) are ionization techniques used when gas phase molecules can be introduced directly into the analyzer from a gas chromatograph. In other analyses, such as high-performance liquid chromatography-mass spectrometry (HPLC-MS),... 

A new technique that resembles the GC-MS technique described here is high-performance liquid chromatography-mass spectrometry (HPLC-MS). An HPLC instrument is coupled through a special interface to a mass spectrometer. The substances that elute from the HPLC column are detected by the mass spectrometer, and their mass spectra can be displayed, analyzed, and compared with standard spectra found in the computer library built into the instrument. 

High-performance liquid chromatography-mass spectrometry (HPLC-MS) is a powerful analytical technique widely used in recent years for the analysis of biomarkers and metabolites. Biomarker determination and quantification, whether metabolic or adducted biomolecules, are commonly used to evaluate exposure and support biomonitoring research, especially in the area of occupational exposure and health. Some of the common problems and strategies of HPLC-MS biomarker analysis involve matrix effects, the use of isotope-labeled internal standard compounds, and sample cleanup usually all of these factors must be evaluated within the development phase of an analysis procedure. Specific examples of biomarker analysis using HPLC-MS include acrylamide, aromatic compounds, and 1-bromopropane, and these examples are discussed in detail. 

Most of the applications of APCI to the area of food science are in conjunction with LC-MS and high-performance liquid chromatography-mass spectrometry (HPLC-MS) and its variations. A few samples of investigations using these techniques are also included to get the flavor of what has been achieved. 

---