Biological substances analysis

Analysis of substances (this is a key process in the identification of new or known chemical and biological substances. Methods of analysis include spectroscopic methods, derivatisation and sequencing meth s). 

Applications Real applications of spark-source MS started on an empirical basis before fundamental insights were available. SSMS is now considered obsolete in many areas, but various unique applications for a variety of biological substances and metals are reported. Usually, each application requires specific sample preparation, sparking procedure and ion detection. SSMS is now used only in a few laboratories worldwide. Spark-source mass spectrometry is still attractive for certain applications (e.g. in the microelectronics industry). This is especially so when a multi-element survey analysis is required, for which the accuracy of the technique is sufficient (generally 15-30% with calibration or within an order of magnitude without). SSMS is considered to be a... 

Rhillips, T. M. S. R. D., Immunoaffinity analysis of substance R in complex biological fluids Analysis of submicroliter samples. Journal of Liquid Chromatography and Related Technologies 25, 2889-2900, 2002. 

Moisture analyses are important because samples contain water either as chemically combined hydrates or as occluded surface-adsorbed moisture. Water is an inherent part of most biological substances and constitutes >90% of the fresh weight of some plant materials. To afford reproducible analytical results, samples are usually dried before analysis and the percentage composition of the sample is then calculated on a dry basis. 

A different, but no less severe problem, is encountered with the analysis of unknown biological substances by field desorption, laser desorption, and/or laser assisted field desorption mass spectrometry. A priori, it is not known at what point in time a component of interest is desorbed. This makes it difficult, if not impossible to time a scan or several scans in such a way that a representative spectrum is obtained. Again the answer to the problem is found by integrating the ion output over the entire sample or repeatedly over portions of the sample profile as it emerges from the ion source. 

With many sensitive liquid chromatographs, little or no pretreatment is necessary, but with GLC partial purification and isolation are required. Since most biological substances have low volatility or poor thermal stability, it is usually necessary to prepare suitable volatile and stable derivatives before analysis. At present, pretreatment methods involve little or no specialized instrumentation, but this will undoubtedly be developed for use with faster automated chromatographs. Methods of sample injection for GLC are relatively crude and an internal standard is necessary to compensate for errors in the volume injected. If large numbers of samples are to be analyzed repeatedly, some form of automatic injection, linked to a timing device, will need to be developed (J6, Zl). 

Although a number of Immunochemical methods have been used for the analysis of small molecular weight biological substances, only radioimmunoassay (RIA), enyzme-1Inked Immunosorbent assay (ELISA) and Immuno-affinity assay (lAA), have been developed for the analysis of mycotoxins. Recent developments have led to several quick screening tests and more than 10 types of commercial kits have become available In the last few years (8, 10, 13). In most cases, sample after extraction from the solid matrix and diluted In buffer can be directly used In the assay. Since the application of Immunoassay for several mycotoxins are covered by other speakers, I will only briefly highlight some of the recent progress on these methods. 

MEMS-based biosensors offer uninterrupted analysis of biological substances potentially... 

Chemical analysis conventionally entails two tasks. The first, qualitative analysis, deals with the identification of an unknown substance, typically in a complex environment. Inevitably, some sort of separation technique, be it chromatographic, electrophoretic, or immunological, is employed when analyzing biological substances. The second, quantitative analysis, deals with the determination of the amount of analyte present. Inevitably, some sort of spectroscopic, electrochemical, or mass spectroscopic method is employed to determine the amount of substance present in the sample following the qualitative analysis step. 

Bristow AF, Dunn D, Tarelli E. Additives to biological substances IV. Lyophilization conditions in the preparation of International Standards an analysis by high performance liquid chromatography of the effects of secondary desiccation. J Biol Stand 16 55-61, 1988. 

Analysis of chemical samples and biological substances of nonproteomic origin requires a rather different approach than that implemented for the study of proteins and nucleic acids. Sample collection and introduction may be achieved via aerosol particle collection for volatile compounds and air-bome pathogens or via a direct insertion probe for solid, nonvolatile samples. Alternatively, SPME may be used to extract and preconcentrate volatile compounds present in air, water, or... 

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