Measurement signal

In the absence of an interferent, the total signal measured during an analysis, Sjneas) is a sum of the signal due to the analyte, and the signal due to the reagents, Sn... 

The process of ensuring that the signal measured by a piece of equipment or an instrument is correct. 

The development of methods using sorbents modified with analytical reagents that enable analytical signal measuring directly on the surface by solid-phase spectrometry, visually or by electrothermic atomic absorption spectroscopy (ETAAS) after elution is now a subject of growing interest. 

In a steady state experiment the PIA signal Y is proportional to neq. Measuring the PIA with a lock-in amplifier means exciting the sample with a periodic time-dependent pump photon flux. The latter can be approximated by a square wave that switches between a constant flux and zero photons with a frequency /= 1/r. As shown in Refs. [32] and [33] the PIA signal, measured with a lock-in amplifier Y, shows the same functional dependence on p as ncq in Eq. (9.5). For the monomo-lecular (p-1) and bimolecular (//=2) case the influence of r depends on t, the lifetime of the observed states, as follows ... 

Electron Capture Detector In the electron capture detector (ECD), a beta emitter such as tritium or 63Ni is used to ionize the carrier gas. Electrons from the ionization migrate to the anode and produce a steady current. If the GC effluent contains a compound that can capture electrons, the current is reduced because the resulting negative ions move more slowly than electrons. Thus, the signal measured is the loss of electrical current. The ECD is very sensitive to materials that readily capture electrons. These materials frequently have unsaturation and electronegative substituents. Because the ECD is sensitive to water, the carrier gas must be dry. 

Parameters that have a noticeable influence on the field only if their values are significantly changed. This simply means that they cannot be defined from a useful signal measured with some error. 

Signal measured at five time points with At = 0.5 s and 27 = 2 s... 

Extension of the convolution to the wavelengths, 301 to 307 nm, yields the measured spectrum g(x) shown in Fig. 40.16. The broadening of the signal is clearly visible. One should note that signals measured in the frequency domain may also be a convolution of two signals. For instance the periodic exponentially decaying signal shown in Fig. 40.13 is a convolution of a sine function with an exponential function. 

Of the four strategies given above, the best condition for obtaining independent data for quality control (QC) are satisfied when INAA and RNAA results are compared, because the use of RNAA dramatically improves the selectivity of signal measurement and eliminates or greafiy reduces the measurement uncertainty sotuces, such as spectral interferences. A variety of radiochemical separations and... 

The essence of the DDIF method is to first establish a spin magnetization modulation that follows the spatial variation of the internal magnetic field within the individual pore. Such modulation is created by allowing spins to precess in the internal magnetic field. Then the diffusion-driven time-evolution (often decay) of such a modulation is monitored through a series of signal measurements at various evolution times tD. The time constant of this decay corresponds to the diffusion time of a molecule (or spin) across the pore and thus is a direct measure of the pore size. 

Experimental conditions designed to produce the minimum signal in an assay. It is typically the signal measured in the absence of a test compound and is relevant to the determination of the BACKGROUND signal. Note synonymous with low control. 

The analytical process is a procedure of gaining information. At first, samples contain only latent information on the composition and structure, namely by their intrinsic properties (Malissa [1984] Eckschlager and Danzer [1994]). By interactions between the sample and the measuring system this information is transformed step by step into signals, measured results and useful chemical information. 

Fig. 3. Amide F FTIR (left) and VCD (right) of effectively fully disordered systems, unblocked (L-Lys)2 (bottom) and (L-Lys)3 (top) in D2O, having one and two amide groups, respectively. The large deflection to low wavenumber is due to the terminal COO- group. The breadth of the K3 spectrum is due to different environments for the two C=0 groups. Spectra are offset for clarity, and the actual signals measured are roughly at our detection limits for reasonable S/N (A A 5 x 10-6).

Coupling constant The separation between lines of a coupled signal measured in Hz. 

Intermediate-range nuclear instrumentation consists of a minimum of two redundant channels. Each of these channels is made up of a boron-lined or boron gas-filled compensated ion chamber and associated signal measuring equipment of which the output is a steady current produced by the neutron flux. 

In a so-called competitive immunoassay format the antigen competes with a labeled antigen for a limited number of antibody-binding sites. It can be shown that in this case the ultimate sensitivity of the assay (when the [Ab] approaches zero) is dependent on the equilibrium constant K and the reliability of the signal measurement of the bound fraction at zero dose [15],... 

---