Multiple reaction monitoring method development

Kim et al. [48] developed a rapid, sensitive, and selective LC-ESI-MS/ MS method for fhe deferminafion of lornoxicam in human plasma. Lornoxicam and isoxicam (infernal standard) were extracted from human phasma wifh efhyl acefafe at acidic pH and analyzed on a Sunfire Cis column with the mobile phase of methanol-ammonium formate (10 mM, pH 3) (70 30). The analyte was detected using a mass spectrometer, equipped with electrospray ion source. The instrument was set in the multiple-reaction-monitoring mode. The standard curve was linear (r = 9998) over the concentration range of 0.5-500 ng/ml. The coefficient of variation and relative error for the intra- and inter-assay at four QC level were 0.7% fo -4.2% and —4.5% to 5%, respectively. The recoveries of... 

A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed to detect tumor-promoting diterpene esters of the tigliane and ingenane types within plant extracts. Fractionation on a Cig HPLC column was followed by MS-MS-multiple reaction monitoring (MRM). 

The detection of strongly acidic sulfonates is performed by ESI-MS in the negative ion mode. In SIR the molecular anions, or in the case of polysulfonated compounds the dianions, are selected for detection, while multiple reaction monitoring (MRM) uses a loss of 64 amu [M-SO2] or 80 amu [M-SO2] from the parent anions. It is still unclear which structural elements govern whether mainly SO2 or SO3 is eliminated. The selectivity of MS, especially MS-MS, allows ion-pair extraction to be used for the enrichment of aromatic sulfonates from aqueous samples without interference from humic material as in UV detection. " No reliable LC-MS method with volatile alkylamines has been developed yet, as problems occur in chromatographic and mass spectrometric separation. 

Liquid chromatography, coupled with mass spectrometry and tandem mass spectrometry (LC-MS/MS), is a universal technique for determining toxins in food. The first multiple reaction monitoring (MRM) method for polyether marine toxins was used for the determination of DSP toxins and this technique has been successfully applied to the simultaneous determination of various groups of polyether toxins in shellfish (Draisci et al., 1998, 1999). MRM involves the selection of a precursor ion and its product ion from CID fragmentations and it is highly selective. For azaspiracids, the first validated LC-MS/MS method was developed for the determination of AZAl... 

Kovarik P, Grivet C, Bourgogne E, Hopfgartner G. Method development aspects for the quantitation of pharmaceutical compounds in human plasma with a matrix-assisted laser desorption/ionization source in the multiple reaction monitoring mode. Rapid Commun Mass Spectrom 2007 21(6) 911—919. 

LC coupled with detection by mass spectrometry (MS) offers the potential for excellent sensitivity and specificity. Sample preparations suitable for niacin analysis by LC-UV and other methods should also be suitable for LC-MS. However, chromatographic methods developed for LC-UV or LC-fluorescence methods would in most cases have to be modified due to issues such as ion suppression and problems created by non-volatile species in commonly used mobile phases. Niacin has a relatively low molecular mass (123 Da), and thus in selected ion recording (SIR) mode, there may still be significant interference problems. With instruments that allow a multiple reaction monitoring mode (MRM), however, interference problems can potentially be avoided even without optimized chromatography or sample clean-up. 

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