ASS SPECTROMETRY

M ass spectrometry provides a highly specific method for determining or confirming the identity or structure of drugs and raw materials used in their manufacture. 

M ass Spectrometry. Field desorption mass spectrometry has been used to analyze PPO (179). Average molecular weight parameters (M and Mj could be determined using either protonated (MH + ) or cation attachment (MNa+) ions. Good agreement was found between fdms and data supplied by the manufacturer, usually less than 5% difference in all cases up to about 3000 amu. Laser desorption Fourier transform mass spectrometry was used to measure PPG ion and it was claimed that ions up to m/z 9700 (PEG) can be analyzed by this method (180). 

Liquid C h rom atography/M ass Spectrometry. Increased use of liquid chromatography/mass spectrometry (lc/ms) for structural identification and trace analysis has become apparent. Thermospray lc/ms has been used to identify by-products in phenyl isocyanate precolumn derivatization reactions (74). Five compounds resulting from the reaction of phenylisocyanate and the reaction medium were identified two from a reaction between phenyl isocyanate and methanol, two from the reaction between phenyl isocyanate and water, and one from the polymerization of phenyl isocyanate. There were also two reports of derivatization to enhance either the response or structural information from thermospray lc/ms for linoleic acid lipoxygenase metabolites (75) and for cortisol (76). 

Perkin-Elmer ICP 5000 Can be used for flame and graphite furnace ASS and inductively coupled plasma atomic emission spectrometry (sequential) ... 

Thermal Ionization Mass Spectrometry, TIMS Alpha Spectrometer Systems, ASS Beta Counting Systems, BCS Gamma Spectrometer Systems, GSS... 

Conacher, H.B.S., Page, B.D., Lau, B.P.Y., Lawrence, J.F., Bailey, R, Calway P., Hanchay, J.E, and Mori, B. (1987). Capillary column gas chromatographic determination of ethyl carbamate in alcoholic beverages with confirmation by gas chromatography/mass spectrometry, /. Ass. Official. Anal. Chem., 70,749-751. 

ASS is known to deactivate COX by irreversibly acetylating serine 530 in the active site of COX-1 [116], and correspondingly serine 516 in COX-2 [117]. Hence, Ott et al. were interested in the potential of Co-ASS 31 to acetylate COX [117]. The exact acetylation sites of COX-2 after incubation with Co-ASS were examined by LC-ESI tandem mass spectrometry. In contrast to ASS, incubation with Co-ASS did not lead to acetylation of serine 516, but to acetylation of several lysine residues, namely lysine 166, lysine 346, lysine 432, and lysine 598 (Figure 1.16). Lysine 346 is part of the entrance channel of the active site and thus acetylation could hinder the access of the substrate. Lysine 166 and lysine 432 are close to the heme prosthetic group, and therefore acetylation of these residues could abolish the function of the protein. In analogy to ASS, these modifications can be assimied to be irreversible. 

Volk KJ, Hill SE, Kerns EH, Lee MS (1997) Profiling degradants of paclitaxel using liquid chromatography- ass spectrranetry and liquid chnanatography-tandem mass spectrometry substructural techniques. J Chromatogr B 696 99-115... 

Atomic Emission Spectrometry with microwave-induced plasma atomisation (MIP-AES) (TNO-design), or inductively-coupled plasma atomisation (ICP-AES)(Kontron ASS 80), depending on the element and its eoncentration. 

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