Analyte precision profile

Figure 6.22 PWG assay dose precision profiles of multiplexed three-analyte immunoassay for two sets of experiments. Dose precisions correspond to standard deviations of analyte concentrations that were back-calculated using corresponding dose response curves. (From Pawlak, M. et al., Proteomics, 2, 383-393, 2002. With permission.)...

Another reason is that there is a high variation in assay precision close to zero dose, i.e., it usually drops asymptotically parallel with the y-axis reaching a minimum value around the middle of the calibration curve (see Fig. 9.5b). Thus, a considerable difference in CV in the absence of the analyte and at the MDC is expected. This is why the concept of functional sensitivity (FS) was introduced [14], defined as the lowest concentration of analyte for which the CV falls below 20%. FS is a parameter that is far more practical than AS and it is derived from the knowledge of the precision profile (PP), i.e., the changes in precision with the concentration of the analyte (Fig. 9.5b) [14]. 

In addition to the usual evaluation parameters for analytical methods (Chapter 16), the sensitivity, detection limit, dynamic range, and precision profile, biosensors are also characterized with respect to the rapidity of their response and recovery. This... 

The performance of an assay can be examined through profiling the precision measured for different sample (analyte) concentrations and conditions. Such assessment at any stage can be regarded as a precision profile. 

Modern analytical techniques can provide accurate and precise profiles of plant and insect cuticular waxes as well as terpenoids. For structural studies the most effective procedures are those based on a combination of mass spectra and GC retention index data. 

The specification development process is a data-driven activity that requires a validated analytical method. The levels of data needed include assay precision, replicate process results (process precision), and real-time stability profiles. A statistical analysis of these data is critical in setting a realistic specification. Most often, aggregation and fragmentation degradation mechanisms are common to protein and peptide therapeutics. Therefore, the SE-HPLC method provides a critical quality parameter that would need to be controlled by a specification limit. 

No informative experimental data have been obtained on the precise shape of segment profiles of tethered chains. The only independent tests have come from computer simulations [26], which agree very well with the predictions of SCF theory. Analytical SCF theory has proven difficult to apply to non-flat geometries [141], and full SCF theory in non-Cartesian geometry has been applied only to relatively short chains [142], so that more detailed profile information on these important, nonplanar situations awaits further developments. 

To measure the strength of the forces exerted on particles, various analytical techniques have been developed [6, 7]. Unfortunately, since most of these techniques are based on hydrodynamics, assumption of the potential profiles is required and the viscosities of the fiuid and the particle sizes must be precisely determined in separate experiments, for example, using the viscous flow technique [8,9] and power spectrum analysis of position fluctuation [10]. Furthermore, these methods provide information on ensemble averages for a mass of many particles. The sizes, shapes, and physical and chemical properties of individual particles may be different from each other, which will result in a variety of force strengths. Thus, single-particle... 

The luminol reaction has also been used for the CL determination of organic substances such as penicillins [32] and tartrate ion [30] in pharmaceutical preparations by their inhibitory effect on the luminol-iodine and luminol-periodate-manganese(II)-TEA system, respectively. As can be seen from Table 1, the results were quite satisfactory. In the indirect determination of penicillins by their inhibitory effect on the luminol-iodine system, the stopped-flow technique improves the accuracy and precision of the analytical information obtained, and also the sample throughput [32], Thus, in only 2-3 s one can obtain the whole CL signal-versus-time profile and calculate the three measured parameters formation and... 

The precision of the assay for nonreduced samples was demonstrated by the evaluation of six independent sample preparations on a single day (repeatability) and the analysis of independent sample preparations on three separate days by two different analysts (intermediate precision). The RSD values for the migration time were 0.9%. The RSD values for peak area percent of the main peak and the minor peaks in the profile were 0.6 and 12.6%, respectively. The higher variability observed with the minor peaks was determined to be primarily related to the sample heating during preparation for the analysis. These results demonstrate that the use of uncoated fused-silica capillaries in combination with a sieving matrix can provide adequate precision and analyte recovery. 

Figure 3.1 Analytical working curve for a self-indexed luminescent thermometer based on the ratio between the measured excimer (E, 475 nm) and monomer (M, 375 nm) emission bands of l,3-b/s(l-pyrenyl)propane in [C4Cjpyr][Tf2Nj. The optical thermometer is perfectly reversible in the temperature range shown and highly precise, with the measured uncertainties in the ratio (1 /1 ) falling well within the symbol dimensions. The dashed curve represents the temperature uncertainty predicted from explicit differentiation of a sigmoidal fit to the calibration profile 5T = 0T/0R 5R where R = I /Iu- (Reprinted from Baker, G.A., Baker, S.N., and McCleskey, T.M., Chem. Commun., 2932-2933, 2003. Copyright 2003 Royal Society of Chemistry. With permission.)...

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