Confirmation liquid chromatography-mass

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). 

The system relies upon preliminary fractionation of the microbial crude extract by dualmode countercurrent chromatography coupled with photodiode array detection (PDA). The ultraviolet-visible (UV-Vis) spectra and liquid chromatography-mass spectrometry (LC-MS) of biologically active peaks are used for identification. Confirmation of compound identity is accomplished by nuclear magnetic resonance (NMR). Use of an integrated system countercurrent chromatography (CCC) separation, PDA detection, and LC-MS rapidly provided profiles and structural information extremely useful for metabolite identification (dereplication, Figure 14.1). 

R Tiebach, W Blaas, M Kellert, S Steinmeyer, R Weber. Confirmation of nivalenol and deoxinivalenol by on-line liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry. Comparison of methods. J Chrom 318(1) 103-111, 1985. 

D Hurtaud, B Delepine, P Sanders. Particle-beam liquid chromatography-mass spectrometry method with negative ion chemical ionization for the confirmation of oxacillin, cloxacillin and dicloxacillin residues in bovine muscle. Analyst 119 2731-2736, 1994. 

B Delepine, D Hurtaud, P Sanders. Multiresidue method confirmation of macrolide antibiotics in bovine muscle by liquid chromatography-mass spectrometry. J AOAC Int 79 397-404, 1996. 

PC Nachilobe, JO Boison, RM Cassidy, ACE Fesser. Determination of trimethoprim in bovine serum by high-performance liquid chromatography with confirmation by thermospray liquid chromatography-mass spectrometry. J ChromatogrB 616 243 —252, 1993. 

SB Turnipseed, CC Walker, JE Roybal, AP Pfenning, JA Hurlbut. Confirmation of fluoroquinolones in catfish muscle by electrospray liquid chromatography/mass spectrometry. J AOAC Int 81 554-562, 1998. 

Meyer, M.T., J.E. Bumgarner, J.L. Varns, et al. 2000. Use of radioimmunoassay as a screen for antibiotics in confined animal feeding operations and confirmation by liquid chromatography/mass spectrometry. Sci. Total Environ. 248 181-187. 

Mouser, P., Filigenzi, M.S., Puschner, B. et al. (2007). Fatal ricin toxicosis in a puppy confirmed by liquid chromatography/mass spectrometry when using ricinine as a marker. J. Vet. Diagn. Invest 19 216-20. 

P.J. Kijak, M.G. Leadbetter, M.H. Thomas, E.A. Thomson, Confirmation of oxytetracycline, tetracycline and chlortetracycline residues in milk by particle-beam liquid chromatography-mass spectrometry, Biol. Mass Spectrom., 20 (1991) 789. 

Turnipseed, S.B. Roybal, J.E. Rupp, H.S. Hurlbut, J.A. Long, A.R. Particle-beam liquid-chromatography mass-spectrometry of triphenylmethane dyes—Application to confirmation of malachite green in incurred catfish tissue. J. Chromatogr. 1995, 670, 55-62. 

Lewis, J.L. Macy, T.D. Garteiz, D.A. Determination of nicarbazin in chicken tissues by Uquid-chromatography and confirmation of identity by thermospray liquid-chromatography mass-spectrometry. J. Assoc. Off. Anal. Chem. 1989, 72, 577-581. 

Hyphenated methods such as gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS) and a number of other chromatographic and spectroscopic configurations are perfectly suitable for initial characterization of the impurities. Of course, these methods are not always applicable, especially when the authentic material is needed for purposes of structure confirmation, synthesis, or toxicity studies (this subject is discussed in various chapters of this book also see reference 2). 

Use of Solvent Adduct Ions To Confirm Structure of Selected Herbicides with Thermospray Liquid Chromatography/Mass... 

Most of these measurements are still routinely perfonned with immunoassays because of their simplicity, rapidity and relatively low cost, and despite occasional concerns about their reliability and validity. Serum total T has also been quantitated by gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS) and LC-MS-MS. MS-based methods are often used in research smdies or to confirm immunoassay results. The advantage of chromatography coupled with MS is the high specificity not available with immunoassays because they are susceptible to cross-reactions. An immunoassay might measure a host of structurally related compounds in addition to the target analyte. 

Beresford, A.P. Macrae, P.V. Alker, D. Kobylecki, R.J. Biotransformation of amlodipine. Identification and synthesis of metabolites found in rat, dog and human urine/confirmation of structures by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. Arzneimittelfor-schung, 1989, 39, 201-209... 

Till the end of the 1990s, little attention was paid to PTXs, considered then to be a problem restricted to D. fortii proliferations in Japan. Nevertheless, improved analytical methods in recent years by liquid chromatography-mass spectrometry (LC-MS) applied to analyses of plankton hauls rich in Dinophysis spp. and of shellfish [44, 45] led to the suspicion, confirmed with numerous new reports, of a widespread presence of PTXs in Dinophysis spp. 

Kishida K, Quantitation and confirmation of six sulphonamides in meat by liquid chromatography-mass spectrometry with photodiode array detection, Food Control 2007 18 301-305. 

Turnipseed SB, Roybal JE, Pfennig AP, Kijak PJ, Use of ion-trap liquid chromatography-mass spectrometry to screen and confirm drug residues in aquacultured products, Anal. Chim. Acta 2003 483(l-2) 373-386. 

Gas-phase reactions of acylium and thioacylium ions with isocyanate and isothiocyanate were investigated by MS <2005JAM1602>. The use of liquid chromatography/mass spectrometry (LC/MS) for the confirmation and quantification of thiomethoxam has been reported <2005ANA21>. 

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