Metabolites chromatogram

Fig. 1 Chromatograms of urine samples containing THC metabolites detection with fast blue salt RR (A) and fast blue salt B (B). Track Ai and B, metabolite-free urines tracks A,6 and B15 represent ca. 60 ng total cannabinoids per ml urine (determined by RIA).

Barbiturates and their metabolites always appear as red-violet chromatogram zones on a white background with this variant of the reagent [6]. 

While barbiturate metabolites are more intensely colored by the mercury(I) nitrate reagent (q.v.) the unaltered barbiturates react more sensitively to the mercury(II) diphenylcarbazone reagent the detection limits lie between 0.05 pg (Luminal ) and 10 pg (Prominal ) per chromatogram zone [6]. 

Figure 11.4 Chromatograms of plasma samples on a silica-chiralcel OJ coupled column system (a) plasma spiked with oxprenolol (internal standard) (b) plasma spiked with 040 p-g/ml metyrapone and 0.39 p-g/ml metyrapol (racemate) (c) plasma sample obtained after oral administration of 750 mg metaiypone. Peaks are as follows 1, metyrapone 2, metyrapol enantiomers 3, oxprenolol. Reprinted from Journal of Chromatography, 665, J. A. Chiarotto and I. W. Wainer, Determination of metyrapone and the enantiomers of its chfral metabolite metyrapol in human plasma and urine using coupled achfral-chfral liquid cltro-matography, pp. 147-154, copyright 1995, with permission from Elsevier Science.

Figure 13.10 LC-LC chromatogram of a surface water sample spiked at 2 p.g 1 with ati azine, and its metabolites (registered at 220 nm). Conditions volume of sample injected, 2 ml clean-up time, 2.60 min ti ansfer time, 4.2 min The blank was subtracted. Peak identification is as follows 1, DIA 2, HA 3, DEA 4, atrazine. Reprinted from Journal of Chromatography, A 778, F. Hernandez et al, New method for the rapid detemiination of triazine herbicides and some of thek main metabolites in water by using coupled-column liquid cliromatography and large volume injection , pp. 171-181, copyright 1997, with permission from Elsevier Science.

While there is a vast range of different drug structures, there are only a relatively small number of chemical reactions, some of which are shown below in Table 5.13 (p. 199), involved in the production of metabolites. Based on the structure of the drug, it is therefore possible to predict the most likely metabolites. Use may then be made of reconstructed ion chromatograms (RlCs) of mlz values corresponding to the predicted molecular weights of these metabolites to locate them within the LC-MS data obtained. 

Figure 5.41 The total-ion-current (TIC) trace and reconstructed ion chromatograms from the predicted pseudomolecular ions of Indinavir m/z 614) and its mono- (m/z 630) and dihydroxy metabolites (m/z 646), generated from full-scan LC-MS analysis of an incubation of Indinavir with rat liver S9. Reprinted by permission of Elsevier Science from Identification of in vitro metabolites of Indinavir by Intelligent Automated LC-MS/MS (INTAMS) utilizing triple-quadrupole tandem mass spectrometry , by Yu, X., Cui, D. and Davis, M. R., Journal of the American Society for Mass Spectrometry, Vol. 10, pp. 175-183, Copyright 1999 by the American Society for Mass Spectrometry.

One approach to drug metabolism studies is therefore to predict the molecular weights of possible metabolites of the drug under consideration, to use reconstructed ion chromatograms to locate any components that have the appropriate molecular weights and then use MS-MS to effect fragmentation of the (M - - H)+ ions from these metabolites, and then to finally link the m jz values of the ions observed with ions of known structure from the parent drug or from other metabolites whose structures have been elucidated. 

Figure 5.49 (a) Total-ion-current trace, and (b) the reconstructed ion chromatogram of mjz 510.2 0.5 (monooxygenated metabolites) from LC-MS analysis of human microsomal incubation of Glyburide. Reprinted with permission from Zhang, H., Henion, J., Yang, Y. and Spooner, N., Anal. Chem., 72, 3342-3348 (2000). Copyright (2000) American Chemical Society. 

Frdns has demonstrated this possibility with reserpine and rescinnamine hy irradiating at the start zone for two hours and obtaining a characteristic zone pattern (fingerprint) after TLC separation of the photochemically produced derivatives [20J. Huck and Dworcak exposed developed chromatograms with vanilmandelic acid and homovanillic acid zones to diffuse daylight and observed the formation of fluorescent metabolites that were suitable for direct quantitative analysis [21]. 

Fig. I Chromatogram of catecholamines, serotonin and some metabolites together with creatinine A) examination at X = 365 nm, B) examination at A. = 254 nm.

Note The detection limits for flunitrazepam and its 7-nitrodesmethyl metabolites are 1 to 2 ng/ml plasma or 0.5 ng substance per chromatogram zone. 

Figure 4A. Chromatogram illustrating the studies conducted on the enzymatic conversion of the PSP toxins to decarbamoyl metabolites (appended with an "M" in these figures). Conversion of Cl to dcGTXII (GTX IIM) in a homogenate of littleneck clam tissue after 4 and 48 hr.

Figure 5. Gas-liquid chromatograms of the silylated urinary metabolites of Fl-nitrosomorpholine arul 3,3,5,5-tetradeutero- -nitrosomorpholine in the rat (59).

Figure 1 SRM chromatograms of (a) fenamiphos and metabolites and (b) imidacloprid and metabolites. IS refers to the stable labeled isotopes. The values below the names refer to the mass transitions, i.e., M -b 1 -> product ion for the metabolite...

Tissue samples obtained from the different colored regions of the larvae were separately analyzed by HPLC. The white, black, and yellow bands of Monarchs all contained a single, major carotenoid component, lutein (all / -3,3 - d i h yd roxy-13, e - ca ro t e n e), Figure 25.3a. The amount of lutein present in the black and white bands was markedly lower ( 15x) than that in the yellow bands, see below. A small quantity of 13-m-lulein and zeaxanthin were observed to elute immediately following lutein in the chromatogram and the lutein peak was preceded by a unique metabolite that is formed by the cleavage of lutein, see Section 25.4. 

Figure 3.3 GC/MS metabolic profiles of a polar M. truncatula root extract that illustrates the elution regions of various metabolite classes. The (a) normalized chromatogram is dominated by several peaks, but the (b) expanded view of the same root profile reveals a substantially larger amount of information not apparent at first glance.

FIGURE 1.43 Representative HPLC chromatograms of vitamin D metabolites.162 (A) late-eluting peaks (B) calibrator in extracted serum (C) sample from patient with low 25(OH)D3 treated with vitamin D2 (D) sample from patient with high concentrations of 25(OH)D3. Int. Std. = internal standard mAU = milliabsorbance units. (Reproduced with permission from the American Association for Clinical Chemistry.)... 

FIGURE 4.3 Total LC/MS ion chromatogram of an Abbott compound, the analog internal standard, its metabolites and impurities. Depending on the need to assay the polar metabolite, 23 to 50% of the mass chromatogram will not show useful information (arrows). 

Figure 4.7 presents a chromatogram that hastens implementation of the LCnMS program. The LC separation took about 13.5 min to separate metabolites that were structural isomers. The implementation of LC2MS made it possible to use a single MS to support a large clinical study. 

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