Metabolite identification sample preparations

Analytical methodologies, which allow the determination of various surfactants and identification of new metabolites are discussed, especially in Chapter 2. The use of multistep sample preparation methods together with advanced techniques like LC-MS (including various types of interfacing systems) for the final identification of surfactants is described in Chapters 3 and 4. Chapter 5 covers the degradation pathway of the major surfactants, which has been studied... 

The analysis of phytochemicals is a tedious process involving several steps in which care must be taken to avoid degradation and contamination. Recent advancements in extraction, concentration, purification and analytical procedures of phytochemicals have been made, but additional developments are needed to assist in the identification and quantification of the diverse array of phytochemicals present in plants and foods, as well as metabolites in biological samples. Specifically there is a need to automate sample extraction, clean-up, and concentration steps to facilitate the screening of phytochemicals develop analytical methods with improved sensitivity, resolution and throughput that utilize less organic solvents and develop concentration and purification methods to produce analytical standards that are not available commercially. Continued advancements in sample preparation and analytical techniques will assist researchers in their quest to identify and quantify the vast array of phytochemicals present in plants... 

If history is any guide, then we foresee great potential for growth in the field of carotenoid analysis in the coming years. Sample preparation methods that quickly and effectively break down and remove sample matrix while preserving carotenoids intact will improve the accuracy of both parent carotenoid and carotenoid metabolite identification and quantitation. 

Automated, rapid, high-throughput global analysis with minimal sample preparation, used for sample classification Limited ability for metabolite identification and quantification except for NMR... 

Proper sample preparation and analysis are essential in all studies of xenobiotic metabolism. With known standards of the free metabolites and often with just a radioactive unknown, it is customary to test their stability under conditions of analysis. The same caution is not always possible with conjugates, but much can be done to improve the validity of conjugate identification. Not only will greater caution in sample handling improve the chances of correctly identifying conjugates, it will also reduce the endless hours of time spent by metabolism chemists in inventing bizarre pathways to justify the formation of metabolites which never existed in the first place. 

Tiller et al. [289] reported the use of accurate LC-MS/MS data from a Q-TOF system as a first-line approach for metabolite identification studies in the discovery phase of the drug development. In this approach, first, the MS/MS spectrum of the parent compound under conditions of high mass resolution is obtained in order to support the proposed fragmentation pattern by elemental composition data. In the next step of the accurate mass approach to metabolite identification, the in vitro samples of drug candidates from incubations in liver microsomal preparations or hepatocytes are analyzed by LC-MSE on the Q-TOF mass spectrometer. Data are... 

Figure 3 A schematic representation of sample preparation, metabolite isolation, and identification using modern analytical Figure 4 A computational approach for metabolite identification instruments. during drug metabolism studies.

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