Samples receipt

The EPA publishes Series Methods that describe the exact procedures to be followed with respect to sample receipt and handling, analytical methods, data reporting, and document control. These guidelines must be followed closely to ensure accuracy, reproducibility, and reliability within and among the contract laboratories. 

For example, in order to meet the demanding requirements of legislation such as the European Union (EU) Baby Food Directive (Directive 95/5/EC and subsequent revisions), analysts must improve on the scope and sensitivity of multiresidue methods of analysis. This Baby Food Directive, which became effective on 1 July 2002, limits residues of all pesticides to a maximum level of 0.01 mgkg There will also be a banned list of pesticides, annexed to the Directive, which will not permit the use of certain pesticides on crops intended for use in baby food production. As a consequence, food manufacturers often require residue results for raw or primary ingredients within 24 8 h of sample receipt at the laboratory. 

Forensic analysis is usually required for the collection of data in the course of determining whether legislation has been infringed. The customer requires that, above all, there is an unbroken chain of evidence from the time the samples were taken to the presentation of evidence in courts of law. In the laboratory this will include documentation and authorization for sample receipt, sample transfer, sub-sampling, laboratory notebooks, analytical procedures, calculations and observations, witness statements and sample disposal. All of these aspects can be called as evidence in court. 

FIGURE 7.2 Discovery assay cycle, showing major steps from sample receipt to data reporting. 

As shown in Figure 7.2, most assays involve a common series of steps that must be completed in order to report results. These steps include sample receipt, method development, sample preparation, analysis, data processing, and data reporting. While most researchers focus on speeding the analysis step, any of these steps can become bottlenecks. Thus it is important to optimize the whole process. 

Maintenance of an independent quality assurance unit within the laboratory to be responsible for a master schedule, sample receipt, and periodic inspections of the conduct and reporting of each laboratory study. 

Methods of sample handling are well documented and assure a good trail-of-evidence from time of sample receipt at the laboratory to time of the report audit. However, information received from the field for individual samples is often incomplete. 

When sampling on Friday, coordinate sample receipt by the laboratory on Saturday. 

Sample information (including field and laboratory sample identification, sample collection date, date of sample receipt, and dates of sample preparation and analysis)... 

Step 1. Receive the sample according to the guidelines and protocol of the receiving institution. The persons who handle the sample must be properly trained and prepared. To receive and process the sample, the person must wear a laboratory coat, face protection, and gloves. The sample is unpacked and inspected in a hood behind a shield. (Note If the sample is packaged at an altitude different than that of the receiving location, there will be a pressure differential that must be taken into account when opening the sample.) This process should be performed as promptly as possible after sample receipt to minimize decay of shorter-lived radionuclides. 

Samples are often sent to the laboratory requiring chain-of-custody protocol. Chain-of-custody ensures traceability and custody of the samples, as well as ensuring the integrity of the sample identity. Here sample-related activities are recorded, consisting of sample receipt, storage, preparation, analysis, and disposal. Chain-of-custody also ensures that all laboratory records are assembled and delivered. 

Other methods to avoid contamination involve meticulous laboratory practice by personnel. The flow of operations from sample receipt to amplified product analysis involves a sequential series of steps that tend from clean to contaminated. It therefore follows that there should be no move-merit of reagents or equipment in the reverse direction to this flbw. For example, pipettes that are used in the post-PCR... 

Sample Accountability Source records should identify the source and number of subject samples2 received by the bioanalytical laboratory, the date of sample receipt, the condition of the samples upon receipt, and the storage location (e.g., equipment identifiers) and temperature conditions for the duration of storage. Courier receipts of the sample shipment should be maintained in the study file. 

CAC/GL 40-1993, Rev. 1-2003, sets out detailed requirements for laboratories working on residue analyses. They must be specifically designed to allow safe operation for staff and free from contamination that could cast doubt on the results generated by staff working in the facility. For instance, sample receipt, storage, and preparation should be in dedicated areas where potential contamination from external sources can be eliminated. It follows from this that analytical standards used in analyses for confirming the identification and quantification of residues should be prepared in secure areas well isolated from routine analytical work. 

Screening measurements of incident response samples begin as soon as possible after sample receipt and logging. A necessary first step is prescreening to prevent a sample from being taken to a laboratory if its radionuclide content is unsuitably high for the usual controls of personnel radiation exposure and contamination of the analyst, the laboratory, and radiation detectors. External radiation is measured with conventional low-level radiation monitors that include the G-M detector and... 

Some aspects of conventional quality assurance discussed in Chapter 11 cannot be applied to screening processes that require data reporting soon after sample receipt. Nevertheless, statements based on measuring radionuclides—notably their concentrations relative to exposure limits or their absence—must be carefully checked in emergencies because of their impact on efforts for protecting humans and area control and remediation. 

Erroneous values have a way of creeping into results despite the control measures in the Quality Assurance Plan (QAP). The data review process must be designed to remove such mistakes. Data review should accompany each step of the analytical process from sample receipt to calculation of activity. Thereafter, weeding out erroneous values becomes a management responsibility during data compilation for presentation andretention. Especially for the reality checks described below, the data compiler must be knowledgeable about radioanalytical chemistry processes as well as the pattern of analytical results related to sources of radionuclides, or must be assisted by specialists in these topics. 

Sample collection and shipment data review at sample receipt. 

Procedures must be included in the QAP for all other aspects of laboratory operation that can affect data quality, including sample receipt, storage, transfer, and disposal, equipment application, and data collection, processing, reviewing,... 

The basic cost of a radioanalytical chemical method is estimated from the person-hours devoted to analysis from sample receipt to result submission. The associated cost of supplies, supporting efforts, instrument use, and overhead is apportioned among the various analyses that are performed during the same period. Personnel cost is affected by the extent of processing needed to preserve and dissolve the sample and to remove interfering radionuclides. In essence, the simpler the process, the lower the cost. The degree of precision and magnitude of detection level are other cost determinants to the extent that they affect analytical skill, instrumentation, and time requirements. 

Of course, none of the issues introduced above can be considered without knowledge of the analytical sample. As well as the nature and properties of the sample itself, the amount of sample available will affect the method design in terms of the required limit of quantification and the size of the sample aliquot that wiU be used. The practical considerations around the sample as it affects the method design are discussed in Section 9.4.6 along with requirements for sample receipt, storage and use. 

After the required procedures (laboratory SOPs) are completed for sample receipt and documentation, the samples must be logged into the laboratory s Laboratory Information System (LIMS) database, or other method that is described in the applicable SOPs. This step is also commonly referred to as sample accessioning . If sample log-in cannot be completed upon receipt or within the time prescribed by the laboratory SOPs, an explanation for the delay should be documented in the sample receipt records. All samples should arrive with sufficient labeling for unique identification (sample ID), including any duplicates received. In many instances, the laboratory will add another label with additional information, such as a unique laboratory ID. 

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