Calculating concentration from

FIGURE 12.6 Measurement of full agonist affinity by the method of Furchgott. (a) Dose-response curve to oxotremorine obtained before (filled circles) and after (open circles) partial alkylation of the receptor population with controlled alkylation with phenoxybenzamine (10 jiM for 12 minutes followed by 60 minutes of wash). Real data for the curve after alkylation was compared to calculated concentrations from the fit control curve (see arrows), (b) Double reciprocal of equiactive concentrations of oxotremorine before (ordinates) and after (abscissae) alkylation according to Equation 5.12. The slope is linear with a slope of 609 and an intercept of 7.4 x 107 M-1. 

OLS and CLS are complementary techniques. OLS calculates concentrations from a known set of component spectra, and CLS calculates component spectra from a known set of concentrations. The component spectra obtained by CLS can be used for OLS analysis of a new data set, as long as the two data sets have the same components. 

For more practice calculating concentrations from the equilibrium constant expression, go to Supplemental Practice Problems in Appendix A. 

Performance characteristics of ligand-binding assays are estimated using calculated concentrations from the spiked validation samples during prestudy validation and/or from the quality control samples during in-study validation. 

Trace analysis permits some simplification of the quantitative models used to calculate concentrations from measured intensities. In the worst case, where the specimens contain both trace and major elements of varying concentrations, one can at least neglect the effect of the trace elements on the major element intensities. Changes in enhancement and absorption of the trace element intensities due to changes in the major element concentrations will, of course, need to be accounted for. 

EXERCISE 18.1 Calculating Concentration from Partial Pressure... 

The final formula to calculate concentrations from absorbances or equivalent signals including baseline and sensitivity drift correction, therefore, is ... 

In particular, the neutron activation analyst, to whom efficiency curves may be an irrelevance, is not weU served by most spectrum analysis packages. As far as activation analysis is concerned, there is much evidence to show that absolute analysis, calculating concentrations from first principles, is much less accurate than comparative analysis. Apart from aU of the problems which derive from having to use efficiency calibration curves, there are specific problems associated with defining and measuring neutron fluxes and cross-sections which make absolute analysis not worthwhile, in my opinion (although there are those who have devoted a considerable amount of effort into developing absolute neutron activation analysis procedures who would dispute that). For that reason, almost every activation analysis involves irradiation of samples and standards. A direct comparison between them is the simplest solution. 

Calculate concentrations from moles of substances. Substitute these concentrations into the equilibrium-constant equation and solve for the unknown concentration. 

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