Qualitative evaluation and documentation

Positions of separated zones on thin-layer (and paper) chromatograms are described by the Rp value of each substance, where 

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Neither Rp nor Rx values are true constants, but Rx values are greatly more reproducible than absolute Rf values and should be preferred for purposes of identification when comparing sample mobilities to tabulated values. The reproducibility of Rp values depends on many factors, such as quality of the sorbent, humidity, layer thickness, development distance, and ambient temperature (see Chapter 11). 

The optimum method for obtaining tentative identification of a substance is to spot the sample and a series of reference compounds on the same chromatogram. In this way, mobilities of all compounds are compared under the same experimental conditions, and a match in Rp values between a sample and standard is evidence for the identity of the sample. Experimental conditions should be chosen so that the compound to be identified moves to a point near the center of the layer (Rp 0.5) and resolution between spotted standards is as good as possible. If Rp values on silica gel are higher than desired, the polarity of the mobile phase is reduced for Rp values that are too low, the polar component of the mobile phase is increased. If the spots of interest from the sample do not line up with the standards, they are either not the same as any of these compounds or their mobilities have been affected by accompanying extraneous material from the sample. If the latter is the case, sample cleanup (see Chapter 4) or two-dimensional TLC will be necessary. 

Identification of a compound based on mobility in one chromatographic system is only tentative and must be confirmed by other evidence. It is common practice to chromatograph the sample and standards in several thin-layer systems to compare their mobilities, but this provides useful corroborative evidence only if the systems are truly independent. Connors (1974) has defined TLC systems that differ sufficiently in properties to yield independent data for example, an adsorption layer in combination with a reversed-phase layer. Two-dimensional TLC on a two-phase silica gel and C 8-bonded silica gel layer has been used to provide fingerprints of complex mixtures for confirmation of identity (Beesley and Heilweil, 1982). 

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Modern TLC is thus an effective tool for separation of complex solutions into their components. Analysis can be qualitative or quantitative. When the composition or the analysed solution is known approximately, identification of the substance contained in a particular spot by its positional coordinates is frequently adequate. HPTLC provides the means not only for flexible screening procedures but also for demanding quantitative determinations. HPTLC features highly sensitive scanning densitometry and video technology for rapid chromatogram evaluation and documentation. 

Step 6 involves selecting the best of the alternative plans of action implicated by the economic and qualitative evaluations and specifying the recommended warehoirse strategic master plan. The master plan will document the space, equipment, persotmel, and standard operating procednre requirements of the warehouse over the planning horizon. In addition, scaled facility drawings should be included showing the recommended warehouse layout for all revisions recommended by the plan of action. 

Four basic hallmarks of data quality—appropriateness, accuracy, integrity and transparency—are introduced in this document. These hallmarks of data quality represent basic principles that are applicable in many analytical endeavours but are tailored here to the needs of exposure assessment. Through the introduction of these hallmarks, this document provides a common vocabulary and set of qualitative criteria for use in the design, evaluation and use of exposure assessments to support decisions. This general guidance is intended for... 

Chapter 7 is titled Qualitative Methods for Effectiveness Evaluation When Numbers Are Not Enough. Subjects covered are interviews and focus groups, questionnaires and open-ended questions, and observations and document analysis. Again, stress is given to verification of the measures. 

Boundary decisions are exceedingly critical. They must be checked and documented with care since they could have considerable effect on the statement value of the study. The MITRE study [9-5] explored various possibilities and discussed specifically reducing the number of social groups impacted. the limitation of the categories of consequences to be investigated, waiver of higher-level consequential effects, reduction of the time span in the case of future projections or waiver of accuracy of results in the case of solely qualitative evaluation. 

The qualitative evaluation of laser-induced effects was based on an analysis of lesions and surrounding liver parenchyma before and after the evaluation periods, and included documentation of the morphology of lesions as seen in T2- and Tl-weighted spin-echo (SE) and gradient recalled echo (GRE) sequences. Quantitative data were obtained by volumetric calculation of tumor and necrosis volumes before and after intervention with the formula (axbxc)x0.5y where a was the maximum anterior-posterior diameter, fiwas the maximum lateral-medial diameter and c was maximum cranial-caudal diameter. 

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. 

Qualitative and quantitative acceptance criteria for the PARCC parameters are derived in the planning phase. Whether they are specific statistical values or represent accepted standards and practices, they must be always selected based on the project objectives and be appropriate for the intended use of the data. The DQI acceptance criteria are documented in the SAP and serve as standards for evaluating data quality and quantity in the assessment phase of data collection process. The primary DQIs are established through the analysis of field and laboratory QC samples and by adhering to accepted standards for sampling and analysis. 

In today s industry, digital cameras have replaced most video systems. All information about the illumination system, data processing equipment and image output system given in Section 7.3 also apply here. Only the current software determines how to achieve a qualitative and/or quantitative evaluation of chromatograms. For the topic Digital Camera see Documentation , Section 8.5. 

The EPA and OSHA regulations [A-1, A-2, and A-3] apply to facilities from which a release of hazardous material could occur, at or above the quantities specified, as shown in bold in Table 17.A.1. Also shown are the Immediately Dangerous to Life and Health [IDLH] concentrations (for 30-minute exposure) [A-4] the Lower Flammable Limits and Heats of Combustion for combustible materials and the EPA toxic, thermal-radiation, and overpressure endpoints for public-exposure evaluations. N/L indicates that the chemical is not listed in the pertinent document. Estimated values are shown with a superscript ( ). Where no inhalation-toxicity data were available, the oral dose that caused 50% fatalities is shown only to indicate qualitatively the systemic toxicity (for example, an oral LD50 of 1000 mg/kg would be considered relatively nontoxic). The data are for pure chemicals, except where otherwise indicated, that is, without added diluents. Additional hazardous-properties information can be obtained via the Sax No. [A-6]. 

Most of the evaluation of the He plumes in the ocean has been qualitative or semi-quantitative in nature. However, there are increasing attempts to incorporate He into Ocean General Circulation Models (OGCMs) in order to understand how such models ventilate the mid-depth and deep-water masses. An early attempt of He simulations in an OGCM has been documented by Farley et al. (1995). The results of the model simulations indicate that the model can roughly close the helium balance and reproduces most of the major observed features of the He field in the ocean. At the same time, the simulations show many shortcomings of the model and future work will contribute to... 

As an analytical approach to residue analysis, immunoassay methods are not well characterized, and no validation protocols have been established. The Association of Official Analytical Chemists, whose primary purpose is validation of analytical methods, established a Task Force on Test Kits and Proprietary Methods (2), which has addressed some of the issues relating to immunoassay methods. The International Union of Pure and Applied Chemistry s Commission on Food Chemistry has established a Working Group on Immunochemical Methods, whose first project is to develop draft guidelines on criteria for evaluation, validation, and quality control for r o-immunoassay methods (10). Similar guidelines for EIAs will also be developed. These documents will assist in development and standardization of requirements for precision for both between-laboratories and within-laboratory andyses, accuracy, and ruggedness, and— for qualitative methods— false positive and false negative rates. 

The third most common method for collecting data in qualitative research designs is known as document analysis. While the thoughts, words, and actions of research subjects are essential, generating thick description requires a complete description of the context in which these dioughts and words are formed and actions take place. Course syllabi, copies of lab experiments, copies of student evaluation forms, and copies of research proposals are typical examples of documents gathered to analyze in a qualitative research design. 

Physical values like crystal structure and the Young modulus are cited, which may play a dominant role in mechanical/tribological loadings. Additionally values for microhardness and oxidation resistance are given. More than others these two values are a function of the test system, the test parameters, and the evaluation method. At this point very strong deviations appear (e.g. hardness of SiC HV 1400 — 6000). In many cases the boundary conditions of the investigations are not documented (e.g. no load specification for hardness testing). For this reason values for hardness and oxidation resistance have a qualitative character more than others. 

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