Sensitive and selective gas chromatography-tandem mass spectrometry method for the detection of nitrobenzene in tobacco smoke.

Nitrobenzene, a potentially harmful compound found in tobacco smoke, has been largely excluded from prior analysis due to difficulties with quantification. Quantifying harmful compounds in cigarette smoke is useful to compare products, to examine the impact of design parameters on delivery, and to help estimate exposures. A sensitive high-throughput method has been developed for quantifying nitrobenzene in machine-generated mainstream cigarette smoke using isotope dilution gas chromatography-tandem mass spectrometry (ID-GC-MS/MS).

Method for the Determination of Ammonia in Mainstream Cigarette Smoke Using Ion Chromatography.

Ammonia in mainstream smoke is present in both the particulate and vapor phases. The presence of ammonia in the cigarette filler material and smoke is of significance because of the potential role ammonia could have in raising the "smoke pH." An increased smoke pH could shift a fraction of total nicotine to free-base nicotine, which is reportedly more rapidly absorbed by the smoker.

Rapid analysis of Lewisite metabolites in urine by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry.

A high-throughput method has been developed for determining Lewisite [dichloro(2-chlorovinyl)arsine] exposure by measuring the urine metabolite 2-chlorovinylarsonous acid (CVAA) and the oxidized metabolite 2-chlorovinylarsonic acid (CVAOA). The rapid sample preparation included a simple dilution of 400 microL of urine with 40 microL of water and 1 mL of buffer containing an internal standard and brief centrifugation prior to analysis by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (ICP-MS). CVAOA and CVAA were eluted isocratically with retention factors of approximately 3.

Nylon-6 capillary-channeled polymer (C-CP) fibers as a hydrophobic interaction chromatography stationary phase for the separation of proteins.

Nylon-6 capillary-channeled polymer (C-CP) fibers are used as the stationary phase for the hydrophobic interaction chromatography (HIC) separation of a synthetic protein mixture composed of ribonuclease A, lysozyme, and holotransferrin. Nylon is a useful polymer phase for HIC as it has an alkyl backbone, while the amide functionality is hydrophilic (in fact ionic) in nature. The combination of a nonporous polymer surface of the fiber phases and high column permeability yields very efficient mass transfer characteristics, as exhibited by narrowing of peak widths with increases in mobile phase linear velocity.

Nylon-6 capillary-channeled polymer fibers as a stationary phase for the mixed-mode ion exchange/reversed-phase chromatography separation of proteins.

Capillary-channeled polymer (C-CP) fibers extruded from nylon-6 are used as the stationary phase for the ion-exchange/reversed-phase mixed-mode chromatographic separation of a three protein mixture. The nylon-6 C-CP fibers are packed collinearly in a 250 x 1.5-mm i.

Enhancing the response of alkyl methylphosphonic acids in negative electrospray ionization liquid chromatography tandem mass spectrometry by post-column addition of organic solvents.

A method to enhance the signal intensity and signal-to-noise of several alkyl methylphosphonic acids in negative electrospray ionization liquid chromatography tandem mass spectrometry (ESI LC-MS/MS) is presented. This class of compound represents the initial metabolites and environmental degradants of the nerve agents: VX, rVX (Russian VX), GB (Sarin), GF (Cyclosarin), and GD (Soman). Compared with the post-column addition of the mobile phase, the post-column addition of aprotic solvents and longer chain alcohols enhance the signal intensity and signal-to-noise ratio (S/N) of the chromatographic peaks by factors of up to 60 and 19, respectively.

Capillary-channeled polymer (C-CP) fibers as a stationary phase in microbore high-performance liquid chromatography columns.

Microbore columns utilizing polypropylene capillary-channeled polymer (C-CP) fibers as the stationary phase in high-performance liquid chromatography (HPLC) have been investigated. The polypropylene C-CP fiber diameter is approximately 50 microm, with eight channels along the periphery of the fiber ranging in diameter from approximately 12 to 35 microm. The polypropylene C-CP fibers were packed into fluorinated ethylene propylene (FEP) tubing, 1.

Hydrodynamic flow in capillary-channel fiber columns for liquid chromatography.

The flow characteristics of capillary-channel polymer (C-CP) fiber liquid chromatographic (LC) columns have been investigated. The C-CP fibers are manufactured with eight longitudinal grooves (capillary channels) extending the length of the fibers. Three C-CP fiber examples were studied, with fiber dimensions ranging from approximately 35 microm to 65 microm, and capillary-channel dimensions ranging from approximately 6 microm to 35 microm.