Down syndrome (DS) is an abnormality of the 21st chromosome that commonly occurs in children born to advanced age women. Amniotic fluid (AF) is usually collected from such women for prenatal diagnosis. This study analyzed human AF supernatants (AFS) by mass spectrometric (MS) approach to search for candidate biomarkers of DS pregnancy. AFS were collected from advanced age pregnant women at 16-1...

A method was developed for screening crops for a range of pesticide residues by liquid chromatography/tandem mass spectrometry (LC/MS/MS). A complete set of LC, electrospray ionization (ESI), and tandem MS acquisition parameters was established for the determination of 108 analytes; these parameters were used for the simultaneous acquisition of 98 analytes in the positive ESI mode and 10 analyt...

A major limitation in quantitative analysis with electrospray ionization mass spectrometry (ESI-MS) is represented by the so-called matrix effects in which the matrix coextracted with the analytes can alter the signal response, causing either suppression or enhancement, resulting in poor analytical accuracy, linearity, and reproducibility. In the direct electron ionization liquid chromatography...

We present a novel analytical platform for peptides quantitative assays in biological matrices based on microscale liquid chromatography fractionation and matrix-assisted laser desorption/ionization mass spectrometric detection using the selected reaction monitoring (SRM) mode. The MALDI source was equipped with a high frequency Nd:YAG laser (1000 Hz) and mounted on a triple quadrupole/linear i...

Ustiloxins are cyclopeptide mycotoxins produced by the pathogenic fungus Villosiclava virens of rice false smut. Ustiloxins A and B as two main mycotoxins were determined conveniently by LC-ESI-MS in the water extract from rice false smut balls which were mostly composed of the chlamydospores and mycelia of the pathogen. Both ustiloxins A and B in the water extract were also quantitatively anal...

Nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry (nanoLC-ESI-MS-MS) was used for the first time in a comprehensive analysis of human urinary phospholipids (PL). PL mixtures from human urine were separated with a reversed phase LC capillary column coupled to ESI-MS-MS. This study used the dual scan method in which two consecutive LC-ESI-MS-MS runs were done in both...

We have developed an analytical method, consisting of ion-pair liquid chromatography coupled to electrospray ionization mass spectrometry (IP-LC-ESI-MS), for the simultaneous quantitative analysis of several key classes of polar metabolites, like nucleotides, coenzyme A esters, sugar nucleotides, and sugar bisphosphates. The use of the ion-pair agent hexylamine and optimization of the pH of the...

BACKGROUND Cerebrotendinous xanthomatosis (CTX) is a rare genetic disorder of bile acid synthesis that can cause progressive neurological damage and premature death. Detection of CTX in the newborn period would be beneficial since an effective treatment is available. We previously described a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) test with potenti...

The development of delayed bitterness in citrus products is a major problem to citrus producers and juice processors worldwide. A rapid and sensitive liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed to quantify the recognized precursors of limonoid derived delayed bitterness, limonoate and nomilinoate A-ring lactones, in a wide variety of cit...

The discovery stage of proteome profiling for disease or expression proteomics typically involves the comparison of different states of a cell, tissue or plasma. In order to obtain better reproducibility and quantitate proteins, 2-dimensional LC liquid separation technique, ProteomeLab PF2D is presented. This method uses chromatofocusing to produce pI fractionation in the first dimension, follo...