Analytical results, documentation

Analytical laboratories need to check their performance with regard to the production of accurate results with satisfactory precision. The most desirable way to ensure the reliability of analytical results is the participation of laboratories into regular interlaboratory tests. An interlaboratory study has to be understood as a study in which several laboratories measure a quantity in one or more identical portions of homogeneous, stable materials under documented conditions, the result of which are compiled into a single document (IUPAC [1994] Prichard et al. [2001]). 

When a sample is received it should have a unique identification, i.e. a number or code. All details about the sample should be recorded. This will include storage conditions and, if it is necessary to transfer the sample from person to person, this should be fully documented. Details of the container and closures should also be recorded. These may have been inappropriate and influence the analytical result. The appearance of the sample on receipt should also be documented. 

Quality assurance (QA) is a generic term for all activities required to maintain quality in analytical results. These include laboratory management structures and sample documentation procedures, as well as the more practical sample preparation and analysis requirements (as described above). The ISO (International Organization for Standardization) develops standards across a wide range of areas, from screw threads to banking cards. The majority of ISO standards are specific to certain areas they are documented agreements containing technical specifications or precise criteria to be used... 

Use of Standardized Methods The first level of AQA is the use of validated or standardized methods. The terms validated and standardized here refer to the fact that the method performance characteristics have been evaluated and have proven to meet certain requirements. At least, precision data are documented, giving an idea of the uncertainty and thus of the error of the analytical result. In both validated and standardized methods, the performance of the method is known. 

Gas chromatography (GC) for amino acid analysis is the alternative to HPLC that has found the greatest acceptance. It requires the preseparation derivatization of the amino acids to render them volatile. For this purpose, amino acids are frequently converted into acylated esters. N-Trifluoroacetyl-n-butyl esters and /V-heptafluorobutyrylisobutyl esters are most commonly employed. There have been comparative studies (3,4) that document similar (if not equivalent) analytical results for GC and the classic ion-exchange chromatographic method applied to a variety of food samples. Comparison (5) of GC to the reversed-phase HPLC determination of amino acids (phenylisothiocyanate derivatized) also shows excellent agreement. 

Similar to the PARCC parameters, acceptance criteria are expressed in qualitative and quantitative terms. Some of them are statistically derived values, while others are purely qualitative and represent industry standards and accepted practices. Quantitative parameters (precision, accuracy, and completeness) are evaluated mathematically and compared to numerical acceptance criteria representativeness, which is a qualitative parameter, is established by comparing documented field and laboratory procedures to applicable standards and specifications. Comparability is estimated as the closeness of analytical results obtained at two different laboratories, and is usually expressed qualitatively. In environmental project work, acceptance criteria for the PARCC parameters are documented in the SAP. 

Inadequate record keeping practices make impossible the reproduction of analytical results at a later date. Data validity cannot be established if laboratory reports are not supported with documentation that allows the tracking of every step in the analytical process for the recalculation of sample results. 

The use of LIMS makes internal review process rapid, reliable, and concurrent with data reporting. While Tier 1 reviewers typically work with hardcopy data, Tier 2 reviewers often access appropriate LIMS modules and review sample and QC data before final results are printed. They will also review the accompanying laboratory documentation that is available in hardcopy form only. Computerized confirmation of numeric acceptance criteria, such as the recoveries of laboratory QC check samples or surrogate standards, significantly reduces time and effort during review. Tier 3 Review is usually conducted on a hardcopy final data after analytical results and support documentation have been compiled into a single package. 

Chlorinated Benzenes. Ten chlorinated benzenes were targeted for analysis in the stack effluents. The analytical results when coal alone was combusted are shown in Table IV. When the coal fuel was supplemented with RDF up to 20%, no consistent increase in the amounts of the chlorinated benzenes occurred although barely detectable amounts of the tetra-, penta- and hexa- isomers were observed during some of eleven different combustions of coal with 20% RDF. Based on these results it appears as if the dichlorobenzenes, reported to be present in the RDF at the 8000 pg/kg level (15,16), were thermally destroyed with high efficiency in much the same manner as that documented above for the PCBs present in the RDF. This suggestion has not been supported so far by experimental results. 

Analytical method the complete process used to determine an analyte or analytes in a sample. The analytical method documents all the individual steps in the process from sampling to reporting the results. 

The decision to develop a pharmaceutical product transfers an active principle or compound from the resource-limited research laboratory into a new environment. In a multi-disciplinary approach the compound is subject to a variety of analytical, pharmacological, toxicological, and clinical tests and trials. From now on methods, results, documentation and the materials created are under strict scrutiny exerted by the developing organization itself and finally by several authorities. Research activities are hardly ever subject to such surveillance and control, concerning, for example the precision and consistency of methods and results. It usually takes time for a researcher to fully acknowlewdge and accept this fact. 

Until recently, obtaining high-quahty chemical standards for the analysis of PFCs was difficult. Although some standards were available commercially, others were available only from manufacturers, and had variable purity and isomer profiles [94,128]. These impurities and structural isomers were not always well documented and could contribute to inaccurate analytical results. For example, shorter chain PFCA impurities observed in a chemical standard of PFTA could result in a negative bias of unknown proportions in quantitation when mixed standard solutions are used without correction [94]. Today, an increasing... 

All laboratories need to demonstrate that their methods are fit for the purpose for which they are intended. The process of obtaining data to demonstrate this fitness for purpose and the resulting documented evidence is called method validation. The purpose of method validation is to determine that one or more of the performance characteristics of the method is satisfactory so that the analytical results obtained will be fit for their intended purpose. 

Necessity of traceability documentation and uncertainty estimation as necessary parameters of an analytical result... 

Results of analytical measurements are a kind of a product of the chemical analyst s work. Both manufactured products (object of analysis) and analytical results must be of an appropriate quality. In addition, the quality of analytical measurements appears to have its own accumulative requirement the quality of every product is a result of comparison of the obtained value (anal3dical result) with the reference value (expected, standard, norm, required). In order for the obtained result to be comparable (authoritative, reliable) to the reference value, its (high) quality must be documented and maintained. The quality of analytical results must be assured in the first place before drawing conclusions about the quality of the examined products. 

It should be noted that the basic and necessary parameters that characterize an analytical result are traceability and measurement uncertainty. An anal3tical result without documented traceability and estimated uncertainty is a source of misinformation. These two parameters are the basic requirements of reliable analytical results. 

Quality control measures are necessary to provide documentation to show that the analytical results are reliable. This is very important since analytical results can form a basis upon which economic, administrative, medical and/or legal decisions are made. 

Carryover is defined as the unintended transfer of a quantity of analyte or reagent by an analytical system from one specimen reaction into a subsequent one. Because carryover introduces error into the analytical results from the subsequent reaction, it should be minimized. Details for determining the extent of analyte carryover are described in the NCCLS document EP 10-A2, Preliminary Evaluation of Quantitative Clinical Laboratory Methods Approved Guideline Second Edition. More elaborate protocols are required to evaluate the extent of reagent carryover. Most... 

Classically, quantitative internal QC involves the analysis of a sample for which the analyte concentration is known, either because the material has been analyzed on many occasions and the distribution of I esults documented, or because it has been analyzed independently and the mean and range of results quoted for the method used. The essence of using the internal QC material is to establish the interval of results that is acceptable the current analytical result is compared with the interval of results deemed to be acceptable (see Chapter 16). The result must then be documented, usually graphically, because it shows the conformity of results and any trends m results that may be occurring. The major aim is to use a means of documentation that ensures that comparative performance is assessed. 

Method Transfer. Method transfer is the process of collecting documented evidence that the receiving laboratories (customers) are capable of running the method. This is based on analytical experiments showing the equivalence of the analytical results obtained in the development and receiving laboratories. These experiments are set up according to the transfer protocol that should contain preapproved acceptance criteria. 

Document the processes used to generate, accept, analyze, store, and archive data and analytical results. 

Internal quality assurance and control procedures are designed to guarantee the reliability of the results generated by the laboratory QA and QC ensure that the reported results contain the appropriate accuracy and precision through stringent monitoring of the analytical process, documentation of procedures and method validation. 

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