Sample receiving

The soil analysis is presented in Table II. Small amounts of 2,4-D and 2,4,5-T were detected in soil samples receiving these herbicides. Background values from the control soils were subtracted from the observed values in treated soils. The samples were not corrected for recovery since it was better than 80% for the method. Residues decreased with time after application. Leaching and microbial decomposition could account for this observation. 

A description of the sample received for testing with identification of source (that is, location from 68... 

The water residue level is also determined from the relative responses of the analytes to the internal standards. The sample residue levels are calculated by comparison with an average response factor determined by triplicate analysis of a five-point calibration curve. Samples receive 5ng of each internal standard (0.1 ngmL ) and are concentrated 50-fold by Ci8 SPE before analysis to achieve adequate instrumental sensitivity. The calculations to determine the residue level in water are outlined in Section 7.3.3. 

Water samples, received from the respective groundwater trials, are analyzed by direct aqueous injection (DAI) by LC/ESI-MS/MS. A 1-mL volume of the water is pipetted into a 1.8-mL autosampler vial. The internal standard solution is added (200 qL) and mixed. The vials are capped and analyzed by LC/ESI-MS/MS using the selected reaction monitoring (SRM) mode. 

This section is not intended to include sample selection, which will probably feature in separate sample plan documentation. Include sufficient detail to describe how the test portion is obtained from the sample received by the laboratory. Include storage, conditioning and disposal details. 

Very often the complete history of samples received into the laboratory may be unclear or incomplete. If it is not possible to find out detailed information about the background of a sample, then the sample should be treated with extra care. Where subsamples of a particular sample are sent to different parts of a laboratory, the labelling of each subsample should include any relevant safety warnings. 

All of the samples analyzed were standard one-inch diameter polished thin sections. Whenever feasible the samples received a final, cleansing polish with 1 pm diamond compound made from commercial graded diamonds embedded in "vaseline". Commercial diamond paste has proved unsatisfactory due to high levels of K, Na, Cl, Si, F, and Ca. Samples are then cleaned with carbon tetrachloride, rinsed in ethanol, and coated with vacuum evaporator. This sample preparation technique was developed during our studies of minor elements [16,17] and has proved to produce consistently contamination-free samples. 

Experimental and theoretical values of A2 are compared in Table IV. The predictions of A2 and the experimental observations are in good agreement for those experiments in TCB and ODCB where the sample received the 160°C treatment and the "spikes" disappeared. 

Note that using an 11 nearest-neighbor rule to classify X would result in 10 A votes and 1 D vote. The only reason a D sample receives a vote is because there are only 10 A samples. This does not pose a problem in this example because of the large number of A samples. However, if there were only 1 A sample and 10 D samples, an 11 nearest-neighbor classification would have 10 D votes and 1 A vote even if the unknown is verv close to the A class and ver> far from the D class. Tlierefore, the maximrtm value of K that should be considered is equal to the number of samples in the class with the fewest members. 

In this same study, inpatient records of children who had been referred to the community clinics indicated that polypharmacy has become more prevalent among inpatient populations as well. While 26% of the 1988 sample received polypharmaceutical treatment in an inpatient psychiatric unit, as many as 42% of the 1992-4 sample children had been treated with concurrent multiple medications during their inpatient hospital stays. 

All of the samples received were used as is and were laboratory, pilot plant, or commercially-produced lignins. 

Cobalt-60 y-Radiolysis Studies. Samples of PIPTBK powder were sealed under vacuum and exposed to 60Co 7-radiation at the National Bureau of Standards in Washington D.C. The samples received 0, 6, 12, and 20 Mrads and the number-average and weight-average molecular weight of each polymer, relative to polystyrene, were determined in THF by GPC. The scission efficiency and the cross-linking efficiency were determined from... 

The properties of a material and, hence, the test results obtained will depend on the processing used to produce the test material or product. Frequently, this is beyond the control of the tester and he or she is only required to characterise the samples received. Nevertheless, if any controlled comparison is to be made it is essential that the test material is produced in exactly the same way. Similarly, any preparation which is performed on the material to produce the test pieces is likely to influence the results. Consequently, it is highly desirable that preparation is standardised and comparisons only made between test pieces produced in the same way, including the direction within the sheet that test pieces were cut. Standard procedures are discussed in chapter 4. 

Effect of Grade, Cut, and Animal Variations. Samples were prepared from the half loins (rib eye) and top rounds of two U. S. Choice and two U. S. Commercial grade beef carcasses. Half of each set of samples received 6.0 db 1.5 megarads of irradiation at — 196°C. at the Natick irradiation facility. The other half of the samples was frozen and held as unirradiated control. 

It consists of a rail-mounted carriage, which carries rows of sample beakers past three stations where each sample receives an aliquot of extractant (usually water), is thoroughly stirred, and has an electrode or electrodes lowered into it. The electrical output from the electrode(s) is passed through an amplifier to a flatbed recorder. Control of the sequence of operations is completely automatic, involving a system of three interlocking motor-driven cam timers, thereby ensuring that each sample receives identical treatment. 

Another part of legal documentation used in sample handling is the custody seal shown in Appendix 10. A custody seal is a narrow paper or plastic strip with adhesive backside. Custody seals were introduced for use on sample containers with samples explicitly collected for projects in litigation. A signed and dated custody seal placed in the field on each sample container connects the container and its lid. A broken custody seal discovered by the laboratory in the course of sample receiving indicates that a sample has been tampered with. There is no reason to use custody seals in this manner on projects that are not under litigation. Flowever, as an external security measure, we may place two custody seals on the front and rear sides of the shipping container lid. 

In the course of sample tracking, data evaluation, and interpretation, field sample IDs may be entered into several different field forms, spreadsheets, and data bases, and appear on maps and figures as identifiers for the sampling points. Because the field records and computer data entry during sample receiving at the laboratory are done for the most part manually, errors in sample ID recording are common. To reduce data management errors, sample numbers must be simple, short, and consecutive. 

The general process of sample transformation into data is the same at every environmental laboratory. The differences are primarily in the manner various tasks are performed by laboratory personnel. To assure the quality of produced data, every laboratory must develop, implement, and maintain a quality system that is documented in the Laboratory QA Manual. The implementation of specific tasks related to sample management, analysis, and quality system, which may be different at different laboratories, is addressed through a set of laboratory s own SOPs. A full service laboratory has dozens of SOPs, describing every laboratory procedure and task from sample receiving to invoicing. The SOPs are updated as necessary and undergo internal review and approval. 

Samples are received at the laboratory by a group of people designated as Sample Custodians who work within the Sample Receiving Section. This section is typically responsible for entering the COC Form information into the LIMS sample storage the preparation of sample containers and coolers on client s request and the disposal of expired samples. These procedures must be documented in laboratory SOPs that are kept readily available at the sample receiving area. 

Sample receiving is not an error-free process it requires attention to detail and a good knowledge of analytical methods. Common sample receiving errors are discussed in Example 4.1. 

Example 4.1 Sample management errors during sample receiving... 

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