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...

platanus acerifolia, london plane tree, a significant source of airborne allergens, is widely grown in shanghai and other cities in china. in recent decades, little has been known regarding the influence of the allergens on sensitizing the population in the shanghai area. the aims of this study were to purify and characterize the two major allergens and to confirm the immunological activities o...

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 ...

for more complex analysers for automated sample processing and plant control. The separation time will continue to decrease; in the past there has been limited interest in fast separations but this could change as automated sample processing is developed. Increasing use of coupled techniques such as GC-GC, liquid chromatography-GC, and supercritical Suid chromatography-GC for the separation of ...