Biology trace analysis

NAA is a quantitative method. Quantification can be performed by comparison to standards or by computation from basic principles (parametric analysis). A certified reference material specifically for trace impurities in silicon is not currently available. Since neutron and y rays are penetrating radiations (free from absorption problems, such as those found in X-ray fluorescence), matrix matching between the sample and the comparator standard is not critical. Biological trace impurities standards (e.g., the National Institute of Standards and Technology Standard Rference Material, SRM 1572 Citrus Leaves) can be used as reference materials. For the parametric analysis many instrumental fiictors, such as the neutron flux density and the efficiency of the detector, must be well known. The activation equation can be used to determine concentrations ... 

Trace enrichment and sample clean-up are probably the most important applications of LC-LC separation methods. The interest in these LC-LC techniques has increased rapidly in recent years, particularly in environmental analysis and clean-up and/or trace analysis in biological matrices which demands accurate determinations of compounds at very low concentration levels present in complex matrices (12-24). Both sample clean-up and trace enrichment are frequently employed in the same LC-LC scheme of course, if the concentration of the analytes of interest are Sufficient for detection then only the removal of interfering substances by sample clean-up is necessary for analysis. 

Tin plate, thickness of tin coating on, determination by x-ray spectrography, 148, 149, 157, 158 Tissues, determination of dry weight by absorptiometry, 297-300 Tissue sections, biological, determination of mineral elements in, 301-305 Titanium, as internal standard in vanadium determination, 188 determination by x-ray emission spectrography, 222, 329 trace analysis by x-ray emission spectrography, 163, 225-229 Topaz, as analyzing crystal, 116-118, 220, 318-327 Total reflection, 112, 117... 

Ihnat M (1988c) Biological reference materials for quality control. In McKenzie HA, Smythe LE, eds. Quantitative Trace Analysis of Biological Materials, pp 331-351. Elsevier Science Publishers, Amsterdam. 

Morrison GH (1979) Elemental trace analysis of biological materials. CRC Critical Rev Anal Chem 10 287-320. 

The structure-selective, electron-capture detector (ECD) is the second aost widely used ionization detector [115-118]. It owes Buch of its popularity to its unsurpassed sensitivity to a wide range of toxic and biologically active coapounds. Consequently, it is widely used in trace analysis for the detemination of pesticides, herbicides and industrial chemicals in the... 

Ward, N.I., Abou-Shakra, F.R. and Durrant, S.F. (1990). Trace element content of biological materials - a comparison of NAA and ICP-MS analysis. Biological Trace Element Research 26-7 177-187. 

MS has been successfully interfaced to both gas and liquid chromatography and the interface to CE has also been successfully developed. CE—MS is serving an analytical role in the area of small sample sizes commonly found in biological, biomarker, or cellular samples. Liquid chromatography is ideally suited for trace analysis when large amounts of sample are available. Compared to HPLC, CE offers different selectivity, higher efficiency, fast method development, and shorter analysis times. 

Although the majority of chiral CEC—MS applications still involve packed columns, few reports on chiral OT-CEC-MS are found in recent literature. The feasibility of coupling OT-CEC (using a short Chirasil-Dex-coated capillary column) to MS and MS/MS for trace analysis of hexobarbital enantiomers in biological fluids was reported by Schurig and Mayer. More recently, Kamande et al. investigated polyelectrolyte multilayer (PEM) coating as a new medium for the separation of chiral analytes, and PEM-coated capillaries were successfully coupled to ESI/MS for the stereoselective analysis of five /1-blockers. 

Helbing KS, Schnid P, Schlatter C (1994) The trace analysis of musk xylene in biological samples problems associated with its ubiquitous occurrence. Chemosphere 29 477-484... 

Hawk, G.L. and Kingston, H.M., Laboratory robotics and trace analysis in Quantitative Trace Analysis Biological Materials, Edited by McKenzie, H.A. and Smythe, L.E., Elsevier, Amsterdam, 1988. 

The possibility of contaminating the sample with the elements under investigation during the various steps is a major risk in trace analysis. The precautions required in order to minimize this problem are similar to those already identified when dealing with biological materials used for total element determinations. Heydom Ver-sieck et al. Stoeppler Behne and Aitio et al. have diam ed the extent... 

Recently, in many demanding sample preparation situations, more selective sorbents have been used. Affinity type sorbents, particularly immunosorbents, have gained popularity in trace analysis, not only for biological macromolecules but also for small molecules, like aflatoxins. MIPs have properties resembling those of affinity phases and therefore they may find unique applications where other sample pretreatment methods are tedious. This relates both to the separation of a single analyte and to the separation of a group of related analytes from the sample matrix. 

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