Sampling integrative

Sample Integrity. In order to be able to rely on the results of measurements, it is necessary to be sure that the sample as analy2ed is the same as it was when collected, and that it is properly identified in the field, in the laboratory, and in the report. Transit times and temperatures should be within the limits allowed for the type of sample and analysis. A series of documents which estabhsh a chain of custody should exist so that it is possible to be sure that the right result goes with the right sample. 

Spatial and temporal transfer of sample extract with minimum and/or known effects on sample integrity... 

Obtaining the aqueous solution to analyze is often a challenge in materials analysis. Thin films usually can be dissolved by acids without dissolving the underlying substrate, however sometimes this is difficult. A film can also be oxidized and the oxide dissolved. Temperatures involved in this procedure are sometimes quite elevated so care must be taken to maintain sample integrity. The chemistry of the sample must be kept in mind so that the limits of the analysis are known. 

Periodically monitor the employee throughout the work day to ensure that sample integrity is maintained and cyclical activities and work practices are identified. 

Exhibit 2-8. Sample Integrated PSM and ESH Management Process Flow Diagram... 

Chau ASY, Caeron J and Lee H-B (1979) Analytical reference materials. II. Preparation and sample integrity of homogeneous fortified wet sediment for polychlorinated hiphenyl quality control studies. J Assoc Off Anal Chem 62 1312-1314. 

The spatial and temporal scope of the study determines the quantity of samples that require processing and storage and can put great pressures on laboratory capacity, potentially increasing the risk of compromising sample integrity and affecting the study quality. 

Field fortification samples may be shipped with field samples but not with controls. Controls should be kept separate from treated samples and may be placed in a separate container within the container used to ship the treated samples. Samples shipped overnight should be shipped in coolers with sufficient dry-ice to maintain the samples in a frozen state for at least 48 h in case a delay in shipment of the samples occurs. Samples should not all be shipped together in one shipment but should be split to ensure that all the samples would not be lost at the same time. A chain of custody form should accompany each separate cooler or shipping box and should list each sample that is in each box. The receiver of the shipment should fill out the chain of custody form and record the conditions of the samples upon arrival at the analytical laboratory indicating whether or not the samples were frozen, ambient, or otherwise upon arrival and if the sample integrity had been compromised during shipping. 

Approximately eight pounds of fruit constituted each analytical sample 11, 14), the number of fruits per sample varied from ten to thirty. Fruits were selected at random from within a peripheral band around the tree 3 to 6 feet above the ground. Individual samples were constituted with fruits from six to eight trees and replicate samples were taken from different groups of trees. In some cases, samples of deciduous fruits were collected from three trees and additionally involved a portion of fruit from the upper quarter of the tree. Duplicate, or more generally triplicate, samples were utilized for analyses. All fruits for penetration studies were collected in paper bags, which were immediately stapled to ensure sample integrity. 

Glass jars make good containers because they are more likely to isolate soil samples from possible contamination. They can, however, break. It is important to remember that the composition of lid liners may be important in maintaining soil sample integrity. Liners can have the same drawbacks as plastic or paper containers. 

A good sample custodian is one who has all the analytical laboratory skills outlined in Chapter 1 (see Section 1.5) and utilizes them in executing any analytical laboratory operation. A conscientious and careful laboratory technician will succeed in maintaining sample integrity. See Workplace Scene 2.2. 

If the integrity of a sample is called into question, a paper trail, or chain of custody, must be examined in order to discover errors. This chain of custody documents who had custody of the sample and what actions were performed so that the sample integrity can be verified. 

Stability of surfactants in a water matrix, even using different preservation agents, is poor and serious, quantitative and qualitative changes in sample integrity occur if the storage exceeds 7 days. The most suitable preservation additive is formaldehyde (minimum 3%) for non-ionic surfactants and LAS, and acidification to pH < 3 for benzene and naphthalene sulphonates. However, storage for longer than 7 days is not recommended. 

The elimination of mannal sample handling with the inherent gain in safety and, to some extent, the elimination of operator error (and being able to maintain sample integrity). 

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