Nuclear magnetic resonance, collection spectra

The carbon-13 nuclear magnetic resonance spectrum of a 4.7% (w/v) solution of dorzolamide hydrochloride was obtained in deuterated dimethyl sulfoxide, and is shown in Figure 9. The spectrum was recorded using a Brucker model AM-400 NMR spectrometer. The band assignments were referenced relative to dimethyl sulfoxide-ds (39.5 ppm), and the carbon atom assignments (using the same numbering system as just described) are collected in Table 5. 

Fig. 7.4.3a,b Nuclear magnetic resonance (NMR 500 MHz) urine spectra from a patient with severe trimethylaminuria, a Before eating sea fish (TMA = 44 pmol/mmol creatinine, TMA N-oxide not detectable), b After a 300-g sea fish meal [Nijmegen protocol urine collection during the 6-h postprandial period TMA = 322 pmol/mmol creatinine, TMA N-oxide (TMA + TMA N-oxide) = 84%]. The NMR spectrum shows the presence of increased TMA in the pre-load sample as well as the absence of TMA N-oxide. After eating fish the TMA concentration is very high and the ratio is clearly abnormal... 

Use of an integrated system incorporating CCC separation, PDA detector, and LC-MS proved to be a valuable tool in the rapid identification of known compounds from microbial extracts.6 This collection of analytical data has enabled us to make exploratory use of advanced data analysis methods to enhance the identification process. For example, from the UV absorbance maxima and molecular weight for the active compound(s) present in a fraction, a list of potential structural matches from a natural products database (e.g., Berdy Bioactive Natural Products Database, Dictionary of Natural Products by Chapman and Hall, etc.) can be generated. Subsequently, the identity of metabolite(s) was ascertained by acquiring a proton nuclear magnetic resonance ( H-NMR) spectrum. 

Fig. 3.53 >3C nuclear magnetic resonance spectrum of benzyl alcohol in CDC13 sweep width 200 p.p.m. Data reproduced from the Standard Carbon-13NMR Spectra Collection, Sadder Research Laboratories, Division of Bio-Rad Laboratories, Inc. 

In the series of microbubble experiments (ref. 394) included in this chapter, the actual film material, contained in compressed microbubble-surfactant monolayers, was collected for structural determinations using H-nuclear magnetic resonance (NMR) spectroscopy. The resulting spectrum is then compared to the H-NMR spectrum which was obtained beforehand from the partially purified, microbubble surfactant mixture prior to monolayer formation and compression. 

Figure 6 The H-decoupled NMR spectrum of (A) control rat urine and urine collected for 24 h following administration of (B) 10 or (C) 30 mg kg- [1,2,3- C]acrylonitrile. Signals are labelled according to metabolite number (see Figure 8, and the letter of carbon-derived form acrylonitrile (aCH2=bCH2-cCN). Reprinted with permission from Fennell TR, Kedderis GL and Sumner SC (1991) Urinary metabolites of [1,2,3- 3C]acrylonitrile in rats and mice detected by nuclear magnetic resonance spectroscopy. Chemical Research in Toxicology 678-687. Copyright 1991, American Chemical Society.

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