Standard single analyte

Assays utilized conventional ELISA processing except that the reagent volumes were greatly reduced, ranging from 25- to 50-pL well additions. Following a 1-hr block in casein, the monoclonal detection antibody was incubated an additional hour at room temperature. The assay sensihvity from the micro-ELISA was approximately 13.4 ng/mL for rabbit IgG — a result similar to that reported by Silzel et al. (1998). The benefit of the "array of arrays" approach is that 96 samples could be processed for multiple (36 to 144) analytes within the same time interval as a standard single-analyte ELISA. 

Quantitative Analysis for a Single Analyte The concentration of a single analyte is determined by measuring the absorbance of the sample and applying Beer s law (equation 10.5) using any of the standardization methods described in Chapter 5. The most common methods are the normal calibration curve and the method of standard additions. Single-point standardizations also can be used, provided that the validity of Beer s law has been demonstrated. 

Case III - Analyte Detection (A - random). One of the most reliable modes of simple (single) analyte detection obtains when y, B and A are each measured (observed) for every sample processed. Such is often the case, for example, in radiocarbon dating where the age of each unknown artifact is estimated from sequential measurements of the sample, the background, and the radiocarbon dating standard. Thus,... 

In clinical chemistry, interpretation of the data can be quite simple or complex. In the case of MS/MS applications pertaining to a single analyte, all that is needed is the intensity value from the mass of a peak of interest and its internal standard. Viewing of a spectrum is not necessary. For profile methods such as full-scan acylcarni-tines, amino acids, or other compound families, the interpretation is more complex. With multiple related components, calculation of the concentration of many key metabolites is required. The system generally has multiple internal standards, external standards, or both. In addition to the concentration calculations, examination of a profile is often best achieved by viewing the spectra together with the quantitative information. 

R Type of standards (mixed or single analyte) 3. Instrumental Single Mi xed... 

The comparison of single analyte standard curves with mixed analyte standard curves was repeated, adding La flame buffer to all standard solutions. The standard matrix was 0.5 percent La, 10 percent HNO3. These results are presented in Table XV. The only slope ratios which differ from unity by more than one percent are Pb analyzed in a lean flame and Cu analyzed in a lean or rich flame. Therefore, when the analysis of a sample depends on the choice of calibration standards and flame stoichiometry, a La flame buffer added to both samples and standards alleviates the dependence. 

TABLE XV. Comparison of single analyte and mixed analyte standard curves obtained with solutions containing 0.5% lanthanum flame buffer... 

TABLE XVI. Results of the application of the Youden-Steiner screening test for the evaluation of the effects of the following variables A - one step vs three step HN03 c - 100°C vs 175°C digestion and G - single analyte vs mixed standard. B, D, and f are dummy variables. 

Single factor experiments showed that Cu mixed analyte standards give a 25% higher response than single analyte standards for analysis in a lean flame (see Table XIV). 

Thus, the measurement of Cr ions will be possible from Ag+ ions generated from the surface of a silver electrode. The quantity of current used, in coulombs, leads to a precise calculation of the quantity of analyte transformed on condition that the current serves only for the formation of ions Ag+. Standard solutions are not required for these measurements. The absolute quantity of ions formed is determined from the current consumed. The quantity of current Q(C) = /(A) f(s) corresponds to a single analyte. 

The limit of detection is defined as a concentration of substance for which there is an adequately high probability of detection when making a single analytical measurement. The LOD refers to the concentration equivalent to 3 times the standard deviation. 

Use of a single method by a small number of laboratories runs the risk of introducing a method bias into the result. It is recommended that the laboratories are chosen for their high standard of analytical capability, and their ability to apply different methods, where this is appropriate. If necessary the laboratories will also be asked to employ different pretreatment methods. A large... 

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