High throughput analysis of alendronate in human samples with derivatization-free hydrophilic-interactive chromatography mass spectrometry.

A derivatization-free hydrophilic-interactive chromatography-mass spectrometry (HILIC-MS/MS) method was developed for quantifying low levels of alendronate in human plasma. Alendronate was separated and concentrated using calcium co-precipitation and analyzed by HILIC-MS/MS, requiring only a 300 μL plasma sample for each analysis. The method is simpler, safer, and more environmentally friendly than the conventional LC-MS/MS method that requires solid-phase extraction and derivatization steps during sample pretreatment.

Multiple solid phase microextraction combined with ambient mass spectrometry for rapid and sensitive detection of trace chemical compounds in aqueous solution.

Multiple solid phase microextraction (mSPME) combined with thermal desorption-electrospray ionization/mass spectrometry (TD-ESI/MS) was developed to rapidly characterize trace analytes in aqueous solution. A number of commercial available SPME fibers (from 2 to 10 fibers) were simultaneously used for extracting the analytes in solution. The fibers were then bundled together on a holder and subjected for the ambient mass spectrometric analysis.

Solid phase microextraction combined with thermal-desorption electrospray ionization mass spectrometry for high-throughput pharmacokinetics assays.

Labor- and time-intensive sample preparation and liquid chromatography mass spectrometry (LC-MS) analysis are required for traditional pharmacokinetics (PK) studies. In order to simplify and accelerate the analytical process of the PK study, solid phase microextraction (SPME) combined with thermal desorption-electrospray ionization/mass spectrometry (TD-ESI/MS) was developed for rapid characterization of trace drug in biological fluids. Methylphenidate in plasma was extracted and concentrated by direct immersion SPME using fused-silica fibers coated with polydimethylsiloxane.

Formation of Metal-Adducted Analyte Ions by Flame-Induced Atmospheric Pressure Chemical Ionization Mass Spectrometry.

A flame-induced atmospheric pressure chemical ionization (FAPCI) source, consisting of a miniflame, nebulizer, and heated tube, was developed to ionize analytes. The ionization was performed by reacting analytes with a charged species generated in a flame. A stainless steel needle deposited with saturated alkali chloride solution was introduced into the mini oxyacetylene flame to generate alkali ions, which were reacted with analytes (M) generated in a heated nebulizer.

Screening CYP3A single nucleotide polymorphisms in a Han Chinese population with a genotyping chip.

Human cytochrome P450 (CYP)3A is a major P450 enzyme found in the liver and gastrointestinal tract. It plays an important role in the metabolism of a wide variety of drugs, some endogenous steroids and harmful environmental contaminants. It has been shown that CYP3A alleles encoding enzymes with little or no activity are largely created by single nucleotide polymorphisms (SNPs) in the sequences of these genes.