Handling of samples

To establish traceability, a chain of custody should be maintained such that at each step in the collection, transport and analysis of the samples, docirmentation is created to describe and verify the transfers that have occinred. 

faeces and other biological samples should not be collected in contaminated areas, to ensitre that activity measured in the sample is representative of body clearance. The sample should be clearly marked to show the worker s identity and the date and time of sample collection. 

27 Analysis of biological or physical samples involves the detection and quantification of emissions from the radionuclides present by appropriate instrumentatiom In many cases, the radionuclides must first be separated from the sample matrix to allow sensitive and reproducible detection. In some other cases, limitations of the detectors prevent discrimination between radionuclides that have similar emissions (e.g. some actinides) in these cases, the samples must be subjected to chemical separation of the elements (radiochemical separation) before counting. 

Instmmentation for radiometric assessment can be divided into three elasses, that for measuring alpha particles, that for beta particles and that for photon emissions. 

Non-radiometric techniques are also available. For example, ultraviolet radiation fluorimetiy can be used for the assay of uranium, irrespective of the degree of enrichment. Other techniques, such as fission track analysis, neutron activation analysis and inductively coupled plasma mass spectrometry (ICP/MS), can be used to measirre specific radionuclides, but are expensive and will be necessary only in special circirmstances. Counting times for all of these methods will depend upon the activity in the sample, the measurement equipment employed and the precision needed (see Appendix II). 

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Review sterility test method and handling of samples. 

For research applications, ultraccnlrifugcs may be equipped with microprocessors lor programming, as well as automated handling of samples. 

Some general problems associated with the determination of sulfur in coal are nonuniform distribution of pyrite particles, failure to convert all the sulfur to sulfate, and loss of sulfur as sulfur dioxide during the analysis. The nonuniform distribution of pyrite necessitates the collection of many sample increments to ensure that the gross sample is representative of the lot of coal in question. Pyrite particles are both hard and heavy and have a tendency to segregate during the preparation and handling of samples. Because the particles are harder, they are more difficult to crush and pulverize and tend to concentrate in the last portion of material that remains from these processes. 

An unusual requirement with important legal ramifications is that of possession. An unbroken chain of identifiable possession (i.e., chain of custody) must be maintained. All transfers are marked on the samples as to time and date of collection, arrival at the laboratory, and all transfers must be signed by both parties. The security and handling of samples during time of possession must be verifiable as a matter of law. 

In various sections of this paper, the authors appropriately emphasize the needed professional knowledge, experience, integrity and responsibility of the analyst. The handling of samples, the estimation of uncertainties, and the vigilance for unexpected errors also require some familiarity with statistics and possibly the help of a statistician as a consultant. However, the final assignment of uncertainties is the responsibility of the analyst who has actually performed the analyses. 

BSI (1996). Water quality. Sampling Part 3. Guidance on the preservation and handling of samples. BS EN ISO 5667-3. 

In this chapter, the contamination sources of aluminum and the handling of samples from collection to analyte measurement will be discussed, in order to reach reliable results in the determination of aluminum in the ppb range. 

Moving towards more reactive radical initiators and at the same time lowering the polymerisation temperature has proven to be a viable route for increasing selectivity, and experiments have been carried out at 40 °C [96,105], 20 °C [64, 73], 3 °C [73] and 0 °C [105]. Photochemical generation of radicals has led to comparable results [102, 105]. Handling of samples is more convenient using... 

X-ray spectrometry has benefited, as have other physico-chemical analysis methods, from the many recent advances in electronics and micro-computing. We have seen that, for qualitative analysis, software is used for the automatic identification of peaks. For quantitative analysis, the majority of equipment manufacturers provide highly extensive correction software packages. Finally, the automatic handling of samples in the spectrometer is well established (sample handlers with a capacity of 72 to 100 samples). 

The issues are of course not restricted to the production of bulk industrial materials. By looking at the production of polymers in the cells themselves, we can help move on from gene sequence to understand the operation of whole organisms. This is not to duplicate the work of biochemists, who are concerned with individual molecules, but much more to do with ensembles of macromolecules and how structures may be built up, disassembled, migrate and/or stick. The experimental tools and mind set required are the same as for in vitro experiments the handling of samples may be very different and need close collaboration with life scientists. 

The exquisite selectivity of biological receptors can simplify the overall analytical process, with minimiun treatment and handling of samples, facilitating on-line and continuous measurements. 

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