Sampling and sample handling

TCDD). The majority of these samples have been collected and analyzed at an average cost of 700 per sample. This includes per diem, labor, equipment, expendable supplies, transportation, and 400 per analysis by contract laboratories. An evaluation of this data has suggested that field sampling and sample handling methods have a significant impact upon the precision and accuracy of the resulting data which, in turn, impact the cost and feasibility of various remedial options. 

If we were to choose the ideal method for the analysis of any component of seawater, it would naturally be an in situ method. Where such a method is possible, the problems of sampling and sample handling are eliminated and in many cases we can obtain continuous profiles rather than limited number of discrete samples. In the absence of an in situ method, the next most acceptable alternative is analysis on board ship. A real-time analysis not only permits us to choose our next sampling station on the basis of the results of the last station, it also avoids the problem of the storage of samples until the return to a shore laboratory. 

Terms used, methods of sampling, and sample handling will be different for water and submerged solid and semisolid samples. The methods described earlier (i.e., transect and grid sampling) are also applicable to these situations. However, semisolid samples, such as those obtained from lake bottoms, require a special sampler. 

Replicate samples are used to indicate sample uncertainty, which shows the contribution of sampling and sample handling to the overall uncertainty. 

Sampling and sample handling are major challenges when applying enzymatic methodologies to the analyses of substances in complex media like biological fluids, food products, and fermentation broth. Traditional enzymology and... 

Since the variances are not homogeneous, non parametric procedures, based on comparisons of medians rather than of mean values, are used. The dispersion observed for the Zn data indicates that the heterogenity of data can not be attributed to the factors tested here, and is more likely to be associated with the variability of the medium in this river. The results for Sc are different, and may be attributable to the extremely low concentrations (0.25 pg/L) compared with those of Zn and B (around 7 and 38 pg/L respectively). Further investigations should be carried out at higher concentrations of Sc, to check if the contribution of the factors associated with sampling and sample handling are the same. 

Data validation is the final step before releasing results. This process starts with validating the samples and methods used. Then the data are reported with statistically valid limits of uncertainty after a thorough check has been made to eliminate errors in sampling and sample handling, in performing the analysis, in identifying samples, and in the calculations used. 

An advantage to the small masses of sorbent in the disks is that small volumes of solvent may be used to elute the disk. For example, the 4-mm disk requires only 100 pL of solvent. The use of small volumes is quite useful for many analyses, where there are micro amounts of sample and sampling handling must be minimized. 

Flow injection analysis offers many attractive features to biosensor analysis. The reproducibility and the speed are two dominant characteristics when combining FIA with proper sampling and sample handling. It can be used for both enzyme-based assays and immunochemical binding assays. 

Mattiasson B and Hikanson H 1993 Sampling and sample handling - crucial steps in process monitoring and control Trends Biotechnol. 11 136-42 Graf H 1989 PhD Thesis Universitat Hannover... 

Kramer, K.J.M., 1995, Quality Assurance of Sampling and Sample Handling for Trace Metal Analysis in Aquatic Biota, In Quality Assurance in Environmental Monitoring, Quevauviller, Ph., (Ed), VCH. 

This does not mean that all the analytical problems have been solved. Far from it. Evidence from various sources shows that the results of trace element analyses, as currently reported by typical laboratories around the world, may be subject to very large errors indeed. For example, the ratios of highest to lowest laboratory mean values for human blood plasma or serum reported by Versieck and Cornells (1980, see also Ver-sieck, 1985) are 392 (No. of lab. means = 17) for aluminium, 178 (7) for arsenic, 1321 (30) for chromium, 1352 (14) for cobalt 3.2 (36) for copper, 64 (19) for manganese, 7.6 (6) for mercury, 443 (10) for molybdenum, 138 (21) for nickel, 4.5 (19) for selenium, 3.4 (3) for tin, approx. 12.000 for vanadium, and 5.1 (36) for zinc. The authors conclude that many of the disparities between the values reported by different investigators are due to inadequate sampling and sample handling, or to defective analysis. 

While not wishing to diminish the importance of sampling and sample handling, the present author believes that discrepancies of these kinds are in many cases due to defective analysis. Evidence supporting this assertion can be found in the results of many intercomparisons organized by the IAEA in recent years (Parr, 1984, 1985) using some of the reference materials described later in this report. 

Wolterbeek, H.Th., Bode, P., 1995. Strategies in sampling and sample handling in the context of large-scaled plant biomonitoring surveys of trace element air pollution. Sci. Total Environ. 176, 33 3. 

Allan A (1998) Quality assiuance of sampling and sample handling (QUASH) laimched at RIKZ, Groningen. In QUASIMEME Bulletin 5. QUASIMEME Project Office, Aberdeen, pll... 

Sample extraction procedures are often perceived as bottlenecks in analytical methods, as they may be time consuming and require particular attention. In most developed analytical techniques, lipids extraction represents a crucial task and the first step of an efficient analytical method, since the validity of the results depends on proper sampling and sample handling preparation prior to analysis. The task of lipid sample extraction, preparation, and handling has been comprehensively discussed, recently [21],... 

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