Peak wavelength value

For ease of use and wavelength accuracies of 1-2 nm, organic materials or inorganic ions in solution have been recommended as standards (Table II). However, these must be used carefully because (a) the peak maxima are matrix dependent, (b) narrow Instrumental bandpasses are necessary, (c) impurities may affect peak location, and (d) the peak wavelength values have generally not been certified (11). 

Now, starting with 0.05 mL toluene, repeat the procedure to obtain five working solutions l -5 and use solution 5 to plot the absorption curve of toluene again record the Amax values for the peaks of the curve. There is a well-developed peak at approximately 270 nm, and using the five test solutions, measure the absorbance of each at the observed peak wavelength and test the application of Beer s Law. Measure solution 5 also at the wavelength used for benzene, and solution 5 at the wavelength used for toluene. 

The variation of grating efficiency with wavelength shown in Fig. 2c is based on a simple model of diffraction which is valid for a > A. For finer rulings, polarisafion and resonance effects complicate the situation (Palmer 2000). In the simple case, the efficiency drops to 40% of the peak (blaze) value at the following wavelengths (Schroeder 2000). 

Colour value given by 1000 E/d, where E is extinction at the peak wavelength (W nm) and d mm is the cell thickness... 

The fluorescence and absorption spectra of DTT-A.V-dioxidc 20a with polar covalent bonds was studied in THF, toluene, and decalin. The spectral line and peak energy are almost independent of the solvent polarity. The fluorescence spectra of the decalin and toluene solutions (almost the same polarity) are red-shifted by about 5 nm, with respect to the THF solution of higher polarity. No evident solvatochromism was observed. The absorbance and fluorescence excitation spectra (at the fluorescence peak wavelength) for DTT-3, 3 -dioxide 20a (normalized to peak value) was compared. The fluorescence excitation signal is, in fact, dependent both on the density of the excited state (as the absorbance) and on the efficiency of the relaxation from the excited state of the emitting one <2005PCB6004>. 

Indeed, this is not far off the peak wavelength (about 850 nm) experimentally observed for the " Aag " Tag absorption band (Moulton, 1985). The agreement is good, especially when we take into account that we are using free ion Racah parameters, which can be slightly modified in the crystal, and a Sugano-Tanabe diagram with a nonexact CIB value. 

In fact, the 828 nm wavelength obtained for the T2g —> A2g transition would be an average value between tiie absorption and emission peak wavelengths widiin die configurational coordinate model. 

Holmium oxide solution is commercially available in a sealed 1-cm cuvette. It is a very convenient and versatile wavelength standard. The standard is suitable for UV-Vis spectrophotometers typically used in pharmaceutical laboratories, with spectral bandwidth ranging from 2 to 0.5 nm. The certified wavelength values of the peaks are listed in Table 10.3. When a spectral bandwidth of... 

Figure 20 Application of the dynamic simplex to the compensation of system-drift. An artificial example is considered here in which the temperature is ramped linearly with time and the simplex aims to compensate for the changes in the reaction temperature by modifying the flow rate accordingly. The plot compares the change in the peak wavelength when the flow rate is held fixed at its initial value of 12 llmin 1 and when it is adapted dynamically by the simplex algorithm. In the former case, the peak wavelength increases steadily with time due to the increasing temperature which increases the growth rate of the particles. In the latter case, the peak wavelength remains fairly close to its initial value of 508 nm.

As indicated in Section 5.4.5, it is not appropriate to consider the observed spectral absorption characteristic of a single chromophore as a single function and speak of the half-amplitude points as describing the waveform. The peak wavelength and the two half-amplitude points can be used for less critical work. However, the correct description of the waveform requires that the waveform on each side of the pseudo-peak be plotted as an exponential function and the wavelength specified at which this function is equal to 1/e of its peak value. These two 1/e values properly describe the measured spectral response. 

Figure 7. (A) Shift in plasmon resonance peak wavelength upon addition of Biotin Peak wavelength before Biotin addition was at 539.48 nm (P), right after Biotin addition was at 546.36 nm (Q), 1 minute after Biotin addition was at 547.85 nm (R), 2 minutes after Biotin addition was at 548.8 nm (S), 3 minutes after Biotin addition was at 548.88 nm (T), and (B) Response of Streptavidin addition to a Biotin coated fiber The value of the wavelength at which plasmon resonance-related dip occurs was plotted vs. time for an in-line fiber optic biosensor based on structure A.

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