Sample handling collection

The main objective of analysis is to ensure the water supplied to the public meets the relevant standards and does not exceed the recommended concentration of hazardous chemicals. The analyses performed by the water laboratory for compliance purposes should be performed in an accredited laboratory and comply with the recognized standard for technical competence of testing laboratories. A complete analytical procedure should include information on sample handling (collection, transport, and storage), sample preparation (concentrate and separate), analysis (methods to identify and quantify components), analytical quality control (criteria), and reporting of analytical results. 

Sample Handling System. Venous or capillary blood, urine, and cerebrospinal fluid are specimens routinely used in medical diagnostic testing. Of these biological fluids, the use of venous blood is by far the most prevalent. Collection devices such as syringes and partial vacuum test tubes, eg, Vacutainer, are used to draw ten milliliters or less of venous blood. At collection time, the test tubes are carefully labeled for later identification. 

Several manual and continuous analytical techniques are used to measure SO2 in the atmosphere. The manual techniques involve two-stage sample collection and measurement. Samples are collected by bubbling a known volume of gas through a liquid collection medium. Collection efficiency is dependent on the gas-liquid contact time, bubble size, SO2 concentration, and SO2 solubility in the collection medium. The liquid medium contains chemicals which stabilize SO2 in solution by either complexation or oxidation to a more stable form. Field samples must be handled carefully to prevent losses from exposure to high temperatures. Samples are analyzed at a central laboratory by an appropriate method. 

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. 

The sampling took place between August 16 and 24, 1983. Most of the 274 samples collected for shipment to contract laboratories were to be analyzed for the purpose of more fully delineating contamination boundaries. Other samples were collected for comparing sample collection and handling techniques. 

For a detailed discussion of the art of sample handling and data acquisition for blood gas measurements, see National Committee for Clinical Laboratory Standards. Blood gas pre-analytical considerations specimen collection, calibration, and controls Proposed Guideline. NCCLS publication C27-P, Villanova, Pennsylvania, NCCLS, 1985... 

All application verification and soil samples must be individually labeled with unique sample identification (ID) and other identifying information such as study ID, test substance name, sample depth, replicate, subplot and date of collection, as appropriate. Proper study documentation requires that sample lists and labels be created prior to work commencing in the field. Water- and tear-resistant labels should be used since standard paper labels may become water-soaked and easily torn during sample handling. Sample lists should have the same information on them as the labels and are a convenient place to record plot randomization, initials of the individual who collected the sample, and date of collection. As such, the sample list is important in establishing chain of custody from the point of sample collection until its arrival at the laboratory. 

Sample handling and shipment. Once collected, all samples were immediately double-bagged, placed on dry-ice and then transported to field headquarters where... 

Figure 3.4. Simple diagram for the sample handling and hght collection system used for a typical nanosecond TR experiment for a flowing liquid stream of sample. See text for more details.

The popularity of this extraction method ebbs and flows as the years go by. SFE is typically used to extract nonpolar to moderately polar analytes from solid samples, especially in the environmental, food safety, and polymer sciences. The sample is placed in a special vessel and a supercritical gas such as CO2 is passed through the sample. The extracted analyte is then collected in solvent or on a sorbent. The advantages of this technique include better diffusivity and low viscosity of supercritical fluids, which allow more selective extractions. One recent application of SFE is the extraction of pesticide residues from honey [27]. In this research, liquid-liquid extraction with hexane/acetone was termed the conventional method. Honey was lyophilized and then mixed with acetone and acetonitrile in the SFE cell. Parameters such as temperature, pressure, and extraction time were optimized. The researchers found that SFE resulted in better precision (less than 6% RSD), less solvent consumption, less sample handling, and a faster extraction than the liquid-liquid method [27]. 

Synchrotron beam time remains a scarce resource world-wide, however wiA over 30 synchrotron raAation centers eiAer operational or under construction, most prospective users can obtain access to Ae facilities (11). In most cases, beam time is available free of charge for non-proprietary research. Access to a facAty is often by means of a peer reviewed proposal. Adequate equipment for sample handling and data collection is available at most synchrotron raAation laboratories. Many laboratories also provide software for data analysis. 

Previous reports 13] emphasized the importance of sample handling, and indeed because of the very volatile nature of the compounds measured in this type of analysis, sample collection deserves special consideration. In general, narrow mouth glass vials with a total volume in excess of 50 ml are acceptable. The bottles need not be rinsed or cleaned with organic solvents, but simply cleaned with detergent and water, rinsed with distilled water, air dried, and dried in a 105°C oven for one hour. The vials are carefully filled with sample to overflowing (zero head space) and a Teflon faced silicone rubber septum is placed Teflon face down on the water sample surface. The septa may be cleaned in the same manner as the vials, but should not be heated more than one hour because the silicone layer slowly degrades at 105°C. 

In earlier studies, the method of blood collection and sample handling before analysis could also have resulted in variable plasma level measurements. For example, it has been reported that during blood collection of TCAs and phenothiazines, contact with rubber stoppers for extended periods of time could result in spuriously low plasma levels (47, 48). 

Sample handling is simplified as glass can be used for windows, lenses, and any other optical components. In addition, the laser source is easily focused on small sample area. Very small samples can be investigated without time-consuming preparation. It is also possible for the source radiation to be transmitted through optical fibers. The fiber-optic probe can be in contact with the sample or immersed in it. The probe consists of input fibers surrounded by several collection fibers that transport the scattered radiation to the monochromator. This makes it possible to collect spectra directly under relatively adverse conditions. 

Specific tests are available to determine the presence of diazinon or its breakdown products in blood, body tissue, and urine. These tests are not routinely available through your doctor s office and require special equipment and sample handling. If you need the specific test, your doctor can collect the sample and send it to a special laboratory for analysis. This test is only useful if done within a few hours or days of exposure. This is because diazinon is rapidly broken down and excreted from the body. For more information on how to determine if you have been exposed to diazinon, see Chapters 2 and 6. 

Once samples are acquired, voucher specimens must be maintained according to standard accepted methods and the collected specimens must be extracted or otherwise processed to prepare samples for biological evaluation. The goal of sample handling and preparation is to select for positives (remove nuisance compounds), prepare the samples to be compatible with existing (and future) bioassays, and store both the collected unprocessed material and the processed samples in a manner that is easily retrievable and maximizes stability. 

Unless the complete history of any sample is known with certainty, the analyst is well advised not to spend his [or her] time in analyzing it. 7 Your laboratory notebook should describe how a sample was collected and stored and exactly how it was handled, as well as stating how it was analyzed. 

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