Screening and determination of polycyclic aromatic hydrocarbons in seafoods using QuEChERS-based extraction and high-performance liquid chromatography with fluorescence detection.

A rapid, sensitive, and accurate method for the screening and determination of polycyclic aromatic hydrocarbons (PAHs) in edible seafood is described. The method uses quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction and HPLC with fluorescence detection (FLD). The method was developed and validated in response to the massive Deepwater Horizon oil spill in the Gulf of Mexico.

Structural characterization of sulfoaildenafil, an analog of sildenafil.

Phosphodiesterase type 5 (PDE-5) inhibitors represent a class of drugs used primarily in the treatment of erectile dysfunction. Currently, three PDE-5 inhibitors have been approved by the U.S.

Accurate mass measurement using Fourier transform ion cyclotron resonance mass spectrometry for structure elucidation of designer drug analogs of tadalafil, vardenafil and sildenafil in herbal and pharmaceutical matrices.

Phosphodiesterase type 5 (PDE-5) inhibitors are a class of drugs used primarily in the treatment of erectile dysfunction. The Food and Drug Administration (FDA) approved PDE-5 inhibitors include sildenafil citrate, vardenafil hydrochloride and tadalafil. In this study, accurate mass measurements were made by electrospray ionization (ESI) using Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) to elucidate the structures of sildenafil, tadalafil and vardenafil analogs that were found in products marketed as dietary supplements.

Investigation of pyrrolizidine alkaloids and their N-oxides in commercial comfrey-containing products and botanical materials by liquid chromatography electrospray ionization mass spectrometry.

Pyrrolizidine alkaloids (PAs) and their N-oxides are found in several plant families throughout the world. PAs are potentially toxic to the liver and/or lungs in humans and may cause acute liver failure, cirrhosis, pneumonitis, or pulmonary hypertension. PAs are also carcinogenic to animals, and they have been linked to the development of hepatocellular and skin squamous cell carcinomas as well as liver angiosarcomas.

Simultaneous separation of different types of amphetamine and piperazine designer drugs by capillary electrophoresis with a chiral selector.

The recent emergence of a new class of piperazine-type compounds has brought about the need for laboratory screening methods for both seized drugs and toxicological samples. These piperazine compounds, which include 1-benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (TFMPP), exhibit comparable physiological effects and can be substituted for the classic amphetamine-type drugs. We have optimized a chiral capillary electrophoresis (CE) separation that detects a set of 6 piperazine and 4 chiral amphetamine compounds in under 23 min using a 200 mM phosphate buffer at a pH = 2.

Analysis of undeclared synthetic phosphodiesterase-5 inhibitors in dietary supplements and herbal matrices by LC-ESI-MS and LC-UV.

A liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method was developed to screen for the presence of synthetic phosphodiesterase type 5 (PDE-5) inhibitors including sildenafil, tadalafil and vardenafil. The method was applied to the analysis of dietary supplements and bulk herbal materials. Bulk powders or composites of tablets, capsules or liquids were prepared and an extraction of PDE-5 inhibitors was performed using a mixture of acetonitrile and water with sonication.

Optimization of preparative electrophoretic chiral separation of ritalin enantiomers.

Continuous free flow electrophoresis (CFFE) was applied to the preparative chiral separation of ritalin enantiomers. Sulfated beta-cyclodextrin (sbeta-CD) was used as the chiral additive. Liquid chromatography-mass spectrometry (LC-MS) experiments were applied to study the time averaged concentration of sbeta-CD in the separation chamber.