A liquid nitrogen jet-cooled thermal modulator dedicated to comprehensive two-dimensional gas chromatography has been mounted in a GC oven coupled to a high resolution magnetic sector mass spectrometry instrument. The data acquisition parameters of the slow double-focusing magnetic sector MS instrument have been optimized to accommodate the description of the narrow modulated GC peaks. Acquisit...

Analysis of food and beverage samples can present challenges given the requirement for low-level detection, often in complex matrices. General IC detectors may not be routinely capable of achieving the desired detection levels, samples may be in high-level matrices, and target analytes may coelute with other compounds. Since general detectors rely on identification by retention time alone, they...

A liquid chromatography-mass spectrometry (LC/MS) method was developed for the separation and determination of linear alkylbenzenesulfonates (C10-C14 LAS) in environmental water samples using a hydrophilic polymer column (Shodex Mspak GF-310 4D). This method involves a solid-phase extraction of the LAS samples with a Sep-Pak PS-2 cartridge. The LAS components were separated on the column with a...

A sensitive and selective gas chromatography-mass spectrometry (GC-MS) method was developed and validated for the determination of morphine and codeine in human urine. The GC-MS conditions were developed. The analysis was carried out on a HP-1MS column (30 m × 0.25 mm, 0.25  μ m) with temperature programming, and Helium was used as the carrier gas with a flow rate of 1.0 mL/min. Selected ion mo...

This paper describes a gas chromatography-mass spectrometry (GC-MS) method with selected ion monitoring (SIM) for determination of metoprolol in rabbit plasma. Metoprolol and internal standard (IS) atenolol were extracted from plasma and cleaned up by using a single step liquid-liquid extraction. Derivatization was carried out using N-Methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA). Calibra...

The structure of N-linked glycans is determined by a complex, anabolic, intracellular pathway but the exact role of individual glycans is not always clear. Characterization of carbohydrates attached to glycoproteins is essential to aid understanding of this complex area of biology. Specific mass spectral detection of glycopeptides from protein digests may be achieved by on-line HPLC-MS, with se...

A method for the determination of 24 organochlorine pesticides by gas chromatography-mass spectrometry (GC-MS) with negative-ion chemical-ionization (NICI) using programmable temperature vaporizer (PTV)-based large volume injection (LVI) is described. The ion source temperature was determined to be 150 °C for the optimized NICI-selected ion monitoring (SIM) conditions. PTV inlet parameters were...

A method for the simultaneous detection and quantitation of amphetamine and methamphetamine in urine is described. Using solid-phase extraction, amphetamine, methamphetamine, and n-propylamphetamine (internal standard) are extracted from urine samples. Drugs in their free form are identified using gas chromatography/nitrogen-phosphorous detection (GC/NPD), whereas their heptafluorobutyric anhyd...

There is no reference method that is generally acknowledged to be unbiased for the determination of the concentration of any protein in biological fluids. This is probably because mass spectrometry (MS) methods acknowledged as reference methods for determination of low molecular mass substances in biological fluids, e.g. creatinine, have been difficult to adapt for proteins. Here we suggest two...

A mild water stress was imposed upon potted tangerine trees (Citrus sinensis Blanco. cv. Zhuju) by water withholding during early juice sac expansion stage. While fruit growth was inhibited by water stress a growth potential was built up inside the fruit, which was not expressed until rewatering. The more powerful water uptake force of the stressed fruit was caused by its more negative fruit wa...