Sample collection techniques

Monitoring Well Purging and Sampling Form MW and MW Event  

Study Prospective Ground-Water Monitoring Study Study Protocol No. 12345 

Please note the following Reference SOP for purging and sampling is WEI-8DD. Dedicated bladder pumps are used for purging and sampling. Sample IDs are listed on the Chain-of-Custody form. 

The volume of water to be purged from the well must be calculated. Methods for determining purge volume include the use of a flow meter on the discharge line, the discharging of purge water into a calibrated container, and/or purging at a known flow rate for a specific period of time. 

In cases where wells have a screened or open-hole interval partially submerged below the water table and a pump is going to be used for both purging and sampling, the pump should be placed at the midpoint between the top of the water table and the bottom of the screen. If different equipment is going to be used for purging and sampling of the well, the pump should be placed at the top of the water column.  

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Water sample collection techniques differ depending on the source being tested. The minimum number of water samples collected from a distribution system which are examined each month for coliforms is a function of the population. For example, the minimum number required for populations of 1,000 and 100,000 are 2 and 100, respectively. To ascertain compliance with the bacteriological requirements of drinking water standards, a certain number of positive tests must not be exceeded. When 10-ml standard portions are examined, not more than 10 percent in any month should be positive (that is, the upper limit of coliform density is an average of one per 100 ml). 

A first approach to determining explosives on-site might include a combination of specialized sample-collection techniques and subsequent analysis using established IMS technologies or instruments. A second level of development could involve the fabrication of analyzers or analytical systems for an on-site operation and real-time analysis of samples. During the past several years, the first step of development has been demonstrated for explosives in water, in soils, and in a few unique uses. 

Laboratory safety data can be erroneous, and this must always be considered when abnormalities are reported. There are numerous sources of error, which may be related to the study subject (e.g. self-medication, certain foods, undue exercise), sample collection technique, storage and transport, the analytical technique used... 

With these considerations, and others gleaned from the research, system developers can use innovative sample collection techniques to extend the capability of their systems to detect lower concentrations and locate or identify buried explosive bearing objects. 

Substantial sample variability affecting field duplicate precision and, consequently, the total sampling and analysis precision is to be expected for many types of soil samples and even some types of water samples as shown in Example 2.5. High sample variability has been documented for any sample collection technique for VOC analysis (Vitale, 1999 Popek, 1999). Depending on the project DQO, the... 

J. A. Goleb, and C. R. Midkiff, Jr., Firearms Discharge Residue Sample Collection Techniques, Journal of Forensic Sciences 20, no. 4 (1975) 701. 

The nature of isotopic data is discussed in later chapters, but sample collection techniques are discussed here. 

Any measurement on a real-world sample is always a combination of the free and bound gas sample types. This is because the process of taking the gas sample generally requires that the sediment or rock system is disturbed by some mechanical means which creates the mixing of these sample types. Because of this unavoidable interaction, we have recognised the need to consider an intermediate sample-collection technique that measures the more loosely-bound gases liberated into a container containing the core sample. 

Solid sample collection techniques depend on the type of dryer. Since a drying curve is the moisture content as a function of time, it must be possible to obtain material before the drying process is complete. There are several important considerations when sampling material for a drying curve ... 

Laboratory safety data can be erroneous, and this must always be considered when abnormalities are reported. There are numerous sources of error, which may be related to the study subject (for example, self-medication, certain foods, undue exercise), sample collection technique, storage and transport, the analytical technique used (for example, high variability, inappropriate reference ranges, interfering substance in the sample), or to the report (for example, transcription errors). Some of the sources of error are listed in Table 6.4. When there is doubt about the validity of the test, it should be repeated and, if necessary, at a different laboratory. 

Spooner, N., Lad, R., and Barfield, M., Dried blood spots as a sample collection technique for the determination of pharmacokinetics in clinical studies Considerations for the validation of a quantitative bioanalytical method, Anal. Chem., 81(4), 1557, 2009. 

Air Sample collection technique for aromatic hydrocarbons, and related volatile organic compounds," Wadsworth Center for Laboratories and Research, New York State Department of Health, 1981. 

CRTU samples should be segregated from samples collected for CDU or B2MU analysis. Sample-collection techniques have been described under section 5.2.4. Samples should be preserved either to stabilize CDU (with HNO ) or B2MU (with NaOH). Neither of these procedures should adversely affect CRTU analysis (see Attachment 3). 

Agent concentration generated by various methods must be analyzed to verify and determine the reliability of each technique. Theoretically calculated concentrations can only be used as estimates of the generation process. They cannot substitute for acmal concentrations because of the adsorption and absorption effects by generator plumbing and the efficiency to deliver the saturated vapor before dilution. Sample collection techniques and some pertinent analytical methodologies will be discussed. It should be noted that many analytical methodologies are currently used by laboratories and researchers for diverse chemicals. In this chapter we present techniques that have been successfully used for many years. 

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