Analyte, source

The results of activation analysis are subject to well known and common analytical sources of uncertainty, as well as method specific uncertainties, e.g. summarized by Greenberg (1997), and also in Section 2.2. In order for INAA experiments to measure differences in induced activity, i.e. differences due to heterogeneity in the amount of analyte in a given test portion, the experimental procedure is designed to allow only the following uncertainties to be part of the result ... 

Agreement Between First and Second Measures Figure 26-30 With in-person variability comparison of hsCRP with total cholesterol (Ledue and Rifai 2003). (From Ledue TB, Rifai N. Preanalytic and analytic sources of variations in C-reactive protein measurement implications for cardiovascular disease risk assessment Clin Chem 2003 49 1258-71.)... 

Ledue T B, Rifai N. Preanalytic and analytic sources of variations in C-reactive protein measurement implications for cardiovascular disease risk assessment. Clin Chem 2003 49 1258-71. 

Ladenson JH. Non-analytical sources of variation in clinical chemistry results. In GradwohPs clinical laboratory methods and diagnosis. AC Sonnenwirth, L Jarett, eds. St. Louis CV Mosby, 1980 149-92. 

Ramsey, M.H. (1998) Sampling as a source of measurement uncertainty techniques for quantification and comparison with analytical sources. J. Analyt. At. Spectrometry, 13(2), 97—104. 

M. H. Ramsey, Sampling as a Source of Measurement Uncertainty Techniques for Quantification and Comparison with Analytical Sources, J. Anal Atomic Spectrosc., 13 (1998) 97. 

Statland, B.E. and Winkel, P. (1981). Selected pre- analytical sources of variation. In Grasbeck, R. and Ahlstrom, T. (eds.). Reference Values in Laboratory Medicine, John Wiley Sons. 

Samet JM (2007) Traffic, air pollution, and health. Inhal Toxicol 19 1021-1027 Samat JA, Marmur A, Klein M et al (2008) Fine particle sources and cardiorespiratory morbidity an application of chemical mass balance and factor analytical source-apportionment methods. Environ Health Perspect 116 459 66... 

To determine the concentrations of vapor phase alkaloids detected in ETS by APCI mass spectrometry, it is necessary to have vapor phase standards which can be used for instrument calibration. Gas dilution is perhaps the best way to calibrate for compounds in the gas phase. Gas dilution requires that a standard of known concentration and a method for accurately and reproducibly diluting the standard are available. Permeation tubes and diffusion tubes, housed in a constant temperature oven, are well suited for generating gas standards with known analyte concentrations. Table 1 includes the analyte, source, and typical source effusion rates used for investigating ETS along with the ion monitored for quantitative analysis of each analyte. 

Certainly in the case of consumer products, but perhaps not in the case of industrial products, it is usually possible to discover useful information about the likely composition of competitors products from readily available non-analytical sources. Having first ascertained what information is required and why, it is worth considering the following before starting any experiments. 

Nonlinear Calibration Approaches Spectral data can respond nonlinearly to process perturbations due to deviations of the Lambert-Beer law, to the nonlinear characteristics of light detectors or to interactions among analytes. Sources of nonlinear behavior and techniques for the detection of important nonlinear effects in spectral responses have been discussed in the literature [25, 76]. In order to cope with the nonlinear features of spectral data sets, different approaches have been applied to build calibration models. These calibration approaches have almost always been based on NN models and locally weighted regression (LWR) models. 

The planar diode (Figure 2B) is the simplest analytical source. It is used for analysing samples in disk-form. The cathode (sample) and anode are in parallel configuration and are placed inside a tube. 

Harrison WW (1992) Glow discharge considerations of a versatile analytical source. Plenary lecture. Joumai of... 

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