In biological analyses

Yan Z, Caldwell GC, Jones WJ, Masucci JA (2006) Cone voltage induced in-source dissociation of glucuronides in electrospray and implications in biological analyses. Rapid Commun Mass Spectrom 17 1433-1442... 

Melethil S, Swyt CR and Zatta PF (1997) Standardization in biological analyses of aluminum What are the needs In Yokel RA and Golub MS, eds. Research issues in aluminum toxidty pp. 241-252. Taylor and Frauds, Washington, DC. 

R. H. Kennett, T. J. Mckeam, K. B. Bechtol, in Monoclonal antibodies. Hybridomas A new dimension in biological analyses. Plenum Press, New York and London, 1980. 

A prototypical isomeric separation in biological analyses is that of leucine and isoleucine amino acids. Those were (barely) resolved by FAIMS as deprotonated... 

So far, as in Equation (3.33), the hydrolyses of ATP and other high-energy phosphates have been portrayed as simple processes. The situation in a real biological system is far more complex, owing to the operation of several ionic equilibria. First, ATP, ADP, and the other species in Table 3.3 can exist in several different ionization states that must be accounted for in any quantitative analysis. Second, phosphate compounds bind a variety of divalent and monovalent cations with substantial affinity, and the various metal complexes must also be considered in such analyses. Consideration of these special cases makes the quantitative analysis far more realistic. The importance of these multiple equilibria in group transfer reactions is illustrated for the hydrolysis of ATP, but the principles and methods presented are general and can be applied to any similar hydrolysis reaction. 

Aqueous standard solutions are a source of certain difficulties In electrothermal atomic absorption spectrometry of trace metals In biological fluids The viscosities and surface tensions of aqueous standard solutions are substantially less than the viscosities and surface tensions of serum, blood and other proteln-contalnlng fluids These factors Introduce volumetric disparities In pipetting of standard solutions and body fluids, and also cause differences In penetration of these liquids Into porous graphite tubes or rods Preliminary treatment of porous graphite with xylene may help to minimize the differences of liquid penetration (53,67) A more satisfactory solution of this problem Is preparation of standards In aqueous solutions of metal-free dextran (50-60 g/llter), as first proposed by Pekarek et al ( ) for the standardization of serum chromium analyses This practice has been used successfully by the present author for standardization of analyses of serum nickel The standard solutions which are prepared In aqueous dextran resemble serum In regard to viscosity and surface tension Introduction of dextran-contalnlng standard solutions Is an Important contribution to electrothermal atomic absorption analysis of trace metals In body fluids. 

The "method of standard additions" has been employed as a technique for standardization of atomic absorption analyses of metals In biological fluids (13,21) In this procedure, several concentrations of standard analyte are added to samples of the biological fluid to be analyzed The calibration curve which Is obtained after additions of the standard analyte to the biological fluid should parallel that obtained when aqueous standards are analyzed Extrapolation of the standard additions curve back to a negative Intercept on the abscissa furnishes an estimate of the concentration of the analyte In the original sample (21) This technique Is helpful In assessing the validity of methods of trace metal analysis (11,13,58) However, In the author s opinion, the "method of standard additions" Is neither practical nor reliable as a routine method for standardization... 

Almost all of the methods described in Chapter 23 can be used for in vivo analyses, both voltammetric and potentiometric ones. The former are used primarily in the analysis of organic substances, which, within certain ranges of potential, can be either oxidized or reduced. Another popular method is the amperometric determination of oxygen in different biological media with the Clark electrode (Section 23.3). 

LC/MS/MS is the preferred means of detection, quantitation, and confirmation of sulfonylurea herbicides in biological and environmental matrices. Therefore, recommendations for establishing and optimizing LC/MS/MS analyses common to all matrices are given first, followed by specific rationales for methods and sample preparation techniques for plant, soil, and water matrices. 

Reversed-phase HPLC followed by post-column derivatization and subsequent fluorescence detection is the most common technique for quantitative determination of oxime carbamate insecticides in biological and environmental samples. However, for fast, sensitive, and specific analysis of biological and environmental samples, detection by MS and MS/MS is preferred over fluorescence detection. Thus, descriptions and recommendations for establishing and optimizing HPLC fluorescence, HPLC/ MS, and HPLC/MS/MS analyses are discussed first. This is followed by specific rationales for methods and descriptions of the recommended residue methods that are applicable to most oxime carbamates in plant, animal tissue, soil, and water matrices. 

Of the radioassays that are commonly used to quantify americium, a-spectroscopy is used when isotopic analyses of americium must be conducted (e.g., 241Am and 243Am). 243Am is often added as a tracer to estimate the efficiency of the sample preparation method when quantifying 241Am in biological matrices. 

In addition, the removal of organic matter and Fe oxides from soils and sediments is common practice as a pretreatment for soils prior to physical, chemical and biological analyses. The effects of the removal of these components on physicochemical and surface chemical properties of soils will be discussed as well. 

Sabater et al. [3] performed chemical and planktonic analyses at 31—43 sampling sites scattered along the main course of the Ebro (Fig. 1). Twenty-five sites covered from the upper reach down to the Ebro Reservoir to the reservoirs of Flix, Mequi-nenza and Ribaroja, while the other six were downstream up to 30 km from the river mouth. Samples were collected in June and October 2005 and 2006. Other surveys were completed in 2008 and 2009. Physical, chemical, and biological analyses were performed at all sites and were later related to the phytoplankton biomass. 

Molecular fossils have been successfully identified in younger Precambrian rocks and linked to certain classes of biological source material. In organic analyses of ancient sediments the cleaned, pulverized rocks are treated with organic solvents to extract a soluble fraction containing the less complex and more easily identifiable compounds. However, this fraction is more subject to contamination since it is not locked within the rock matrix. Normal alkanes have been identified in extracts of the 3 billion year old Fig Tree Shale. These alkanes have a probable biological origin in cellular lipids. The odd and even-numbered alkanes are evenly distributed, a characteristic of alkanes from ancient rocks. It is uncertain, however, whether these compounds were present at the time of deposition or derived from a later source [24]. 

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