a clinical presentation of a metabolic disorder, often first seen in infants who present with poor feeding, vomiting, tachypnea, acidosis, hyperammonemia, ketosis, ketonuria, irritability, and convulsions or hypotonia and lethargy, findings that are otherwise suggestive of neonatal sepsis diseases with oa isovaleric and propionic acidemias, maple syrup urine disease, medium chain acyl dehydroge...

the lack of authentic standards has limited the quantitative analysis of herbal drugs in biological samples. the present work demonstrated a practicable strategy for the assay of herbs and their metabolites independent of authentic standards. a liquid chromatography–electrospray ionization–mass spectrometry (lc–esi–ms) method for the qualitative and quantitative determination of the metabolites...

methylmalonic acidemia (mma) is usually caused by a deficiency of the enzyme methylmalonyl-coa mutase (mcm), a defect in the transport or synthesis of its cofactor, adenosyl-cobalamin (cbla, cblb, cblc, cblf, cbld, and cblx), or deficiency of the enzyme methylmalonyl-coa epimerase. a comprehensive diagnostic approach involves investigations of metabolites with tandem mass spectrometry, organic ...

SUMMARY Tandem mass spectra obtained from fragmenting peptide ions contain some peptide sequence specific information, but often there is not enough information to sequence the original peptide completely. Several proprietary software applications have been developed to attempt to match the spectra with a list of protein sequences that may contain the sequence of the peptide. The application TA...

1 Selected tandem mass spectrometry (MS/MS) ion monitoring (SMIM) is the most 2 suitable scanning mode to detect known peptides in complex samples when an ion-trap 3 mass spectrometer is the instrument used for the analysis. In this mode, the MS detector 4 is programmed to perform continuous MS/MS scans on one or more selected 5 precursors, either during a selected time interval, or along the w...