Mass spectrometry confirmation

Mass spectrometry confirming peak identity, quantitation based on retention time mg/kg fresh weight Accept... 

Although less expensive than liquid chromatography-mass spectrometry, confirmation by gas chromatography-mass spectrometry (492, 512) is applicable only to the volatile leuco forms and not to chromatic forms of the dyes. The reduced leuco forms of triphenylmethane dyes are volatile and thermally stable enough to be analyzed by gas chromatography-mass spectrometry (492, 512). 

Two homogeneous metal complex water-gas shift catalyst systems have recently appeared 98, 99). The more active of these comes from our Rochester laboratory (99, 99a). It is composed of rhodium carbonyl iodide under CO in an acetic acid solution of hydriodic acid and water. The catalyst system is active at less than 95°C and less than 1 atm CO pressure. Catalysis of the water-gas shift reaction has been unequivocally established by monitoring the CO reactant and the H2 and C02 products by gas chromatography The amount of CO consumed matches closely with the amounts of H2 and C02 product evolved throughout the reaction (99). Mass spectrometry confirms the identity of the C02 and H2 products. The reaction conditions have not yet been optimized, but efficiencies of 9 cycles/day have been recorded at 90°C under 0.5 atm of CO. Appropriate control experiments have been carried out, and have established the necessity of both strong acid and iodide. In addition, a reaction carried out with labeled 13CO yielded the same amount of label in the C02 product, ruling out any possible contribution of acetic acid decomposition to C02 production (99). 

Carpenter, R.A., R.H. Hollowell, and K.M. Hill (1997). Determination of the metabolite of the herbicide dimethyl tetrachloroterephtha-late in drinking water by high-performance liquid chromatography with gas chromatography/mass spectrometry confirmation. Anal. Chem., 69(16) 3314-3320. 

Okuda and Arnold have reported a series of 5- and 6-coordinate chiral indium complexes (e.g. 12), analogous to those previously discussed with yttrium (Table 4), which show varying activities for the polymerization of rac-lactide [71]. The homoleptic species was fluxional, interconverting between a 5-coordinate and fac- and mer-isomers of a 6-coordinate complex. It resulted in controlled polymerization and some stereoselectivity (max. P, = 0.63 and max. Ps = 0.64). MALDI-ToF mass spectrometry confirmed that the chiral alkoxide ligand was an initiating group. 

Mass spectrometry confirmed the structure of a new CI5 alkaloid (31), nupha-cristine (12), containing a hydroxymethyl group at C-l, an aldehyde at C-7, and a double bond between C-6 and C-7, features not previously encountered in this... 

Acute transient urinary retention associated with metamfetamine and ecstasy (3,4 methylenedioxymetamfeta-mine, MDMA) in an 18-year-old man has been described (76). Analysis by gas chromatography-mass spectrometry confirmed the presence of metamfetamine (>25 pg/ml), MDMA (> 5 pg/ml), amfetamine (1.4 pg/ml), and methylenedioxyamfetamine (3.7 pg/ml) in the urine. Bladder dysfunction resulting from alpha-adrenergic stimulation of the bladder neck may have explained the observed effect. 

The molecular formula of a molecule can also be defined by high resolution mass spectrometry (hrms). The observed mass for the molecular ion or pseudo molecular ion must normally be within 5ppm of the calculated mass for El (electron impact) measurements, or within lOppm for Cl (chemical ionization) measurements. It is important to note that high resolution mass spectrometry confirms that some molecules of a particular molecular formula are present in the sample, but does not give any indication of purity. Some other evidence of compound purity will therefore be required. 

Moore L, Wicks J, Spiehler V, Holgate R. Gas chromatography-mass spectrometry confirmation of Cozart RapiScan saliva methadone and opiates tests. J Anal Toxicol 2001 25 520-4. 

Interestingly, oxidation of [lr (biphenyl-2,2 -diyl)(Cl)(PMe3)3] with [NO]Bp4 yields a different paramagnetic species in which a BF unit has been inserted into one of the Ir—C bonds. This species was characterized by X-ray diffraction, and high-resolution mass spectrometry confirmed the formulation. 

Sanchez-Bmnete, C., Albero, B., Miguel, E., and Tadeo, J. L., Determination of insecticides in honey by matrix solid-phase dispersion and gas chromatography with nitrogen-phosphoms detection and mass spectrometry confirmation, J. AOAC Int, 85, 128-133, 2002. 

Y. M., Donald, L.J., Standing, K.G., and Ben-Hayyim, G. (2002) A selenoprotein in the plant kingdom. Mass spectrometry confirms that an opal codon (UGA) encodes selenocysteine in Chlamydomonas reinhardtii gluththione peroxidase. /. Biol. Chem., 277 (29), 25983-25991. 

Intermediates of type 223,227 (226), 231 and 234 could be detected either as the protonated specie or as the sodium complex using electrospray ionization mass spectrometry confirming the above reaction profile [304]. 

MALDI-ToF mass spectrometry confirmed complete incorporation of the respective initiators... 

Alispahic M, Christensen H, Bisgaard M, Hess M, Hess C. MALDI-TOF mass spectrometry confirms difficulties in separating species of the Avibacterium genus. Avian Pathol. 2014 43(3) 258-63. 

H20. Mass spectrometry confirmed that the product was [ 0]-hydroxyatrazine and thus the reaction was hydrolytic. More recendy, further mechanistic studies have revealed that atrazine chlorohydrolase coordinates ferrous iron, which is essential for its catalytic activity (29). Incubating atrazine chlorohydrolase with the chelators 1,10-phenanthroline or oxalic acid removed the required metal with concomitant loss of activity. Chlorohydrolase activity was restored by the addition of Fe(II), Mn(II), or Co(II) salts. Electron paramagnetic resonance (EPR) and electronic spectroscopic studies provided data consistent with a 1 1 metal to subunit stoichiometry. In total, the data indicate that atrazine chlorohydrolase is a metalloenzyme, making this the first report of a metal-dependent hydrolytic dehalogenase. 

Gas chromatograph-mass spectrometry confirmation of drugs Mass spectrometry in the clinical laboratory... 

CLSI (2010) Gas chromatography/mass spectrometry confirmation of drugs approved guideline, CLSI Document C43-A2, 2nd edn. Clinical and Laboratory Standards Institute, Wayne, PA... 

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