Band width 2122 water

Measurements were performed on a Waters 470 HPLC fluorescence detector equipped with a JASCO cuvette accessory and connected to a Perkin Elmer 561 strip chart recorder. Excitation and emission band-widths were 18 nm. Emission spectra were measured for the three excitation wavelengths mentioned above and emission starting from 10 nm higher than excitation up to 700 nm. Fluorescence at fixed wavelengths was measured four minutes after cuvette insertion and expressed as per-millage of the 275/303 fluorescence of 3.0 pM tyrosine in 50 mM HEPES, pH 7.4. Corrections were made for buffer- and blank collagenase fluorescence, and for signal attenuation. 

Recent 170 NMR studies have given us two values for the 170 chemical shifts in oxetane, -12.0 and -20.5 p.p.m., referenced to water (79BCJ3391, 80T3431). The rather wide band width may explain part of this apparent discrepancy. The 170 chemical shift of oxetane and other ethers was found to correlate with the reciprocal of their ionization potentials. 

Self diffusion coefficients can be obtained from the rate of diffusion of isotopically labeled solvent molecules as well as from nuclear magnetic resonance band widths. The self-diffusion coefficient of water at 25°C is D= 2.27 x 10-5 cm2 s 1, and that of heavy water, D20, is 1.87 x 10-5 cm2 s 1. Values for many solvents at 25 °C, in 10-5 cm2 s 1, are shown in Table 3.9. The diffusion coefficient for all solvents depends strongly on the temperature, similarly to the viscosity, following an Arrhenius-type expression D=Ad exp( AEq/RT). In fact, for solvents that can be described as being globular (see above), the Stokes-Einstein expression holds ... 

Apparatus Use a suitable variable wavelength spectrophotometer capable of measuring percent transmittance at 420 nm or a photometer with a 420- 10-nm band width filter. The instmment design should permit the use of a 10-cm cell. When using an instmment with a reference cell, the two cells should be identical with water within 0.2% when the instmment is set at 100% transmittance on one of the cells. 

Another study of water which permits examination of the bending mode is the matrix isolation work of Van Thiel, Becker, and Pimentel (2097). Water was suspended in solid nitrogen at 20°K, and absorptions were assigned to dimers, trimers, and higher polymers. In Table 3-XII I, the shifts (referred to monomeric water suspended in solid nitrogen) and approximate band widths are presented. 

TABLE 3-XIII Relative Frequency Shifts and Band Widths of Polymers of Water in Solid Nitrogen ... 

Tissues (Sunderman Jr. et al., 1985) - Samples cut with a plastic serrated cafeteria knife are digested with a nitric sulphuric perchloric acid mixture as described in the text until clear and colourless and the final volume is about 50 //L. Samples are cooled and diluted to 4 mL with dilute HCI (cone. HCI diluted 1 9 v v with water). 0.2 mL cone. HNO3 is added. Instrumentation Perkin-Elmer HGA-500 AAS with Zeeman correction, lamp current 25 mA, spectral band width 0.2 nm. A = 232.0 nm, 50nL sample injection. Furnace program dry 100°C (r1, hi), 140°C (r60, hlO), 190°C (r30, h5), char 1200°C (r80, h50), atomize 2600°C (rO, h5), clean 2700°C (r1.h3). Argon flow 300 mL/min, decreased to 30 mL/min during the atomization step and last 5 s of the char step. Detection limit 10 /rg/kg dry wt. Imprecision (RSD) within-batch 15% at 76 Ni/g, accurate at 50 hq Ni/g in gelatin. Recovery of 200 ng added Ni 101 8% (mean s). 

Figure 9. Top Percentage of bound water (from TGA analysis) versus pH of albumin solutions. Bottom Amide I band width versus pH of albumin solutions.

Several studies have been reported for the RPLC gradient separation of peptides and/or proteins, where band width o, is given as a function of gradient conditions (varying values of tp and We have selected those examples where enough data are reported to allow comparison of experimental and predicted o, values (model of Table VIII) for a wide range of separation conditions. In some of these studies, values of S for the proteins reported were not known.However, it has been observed (59) that valuesof the solute parameter S(fwater mobile phases) can be related to M (ai roximatdy) as follows ... 

In this study 74) five proteins (l2,000 s A/s 80,0(X)) were separated by gradient RPLC on a 30-nm-pore C4 column with aoetonitrile/water mobile phase 16 runs with a 4>fold variation in Fand 16-fold variation in to were reported. A total of 43 experimental band width values could be compared with predicted values, giving F, 1.01 and SD 0.20. Again this is acceptable i reement. 

Broad and narrow components of the signal are observed in Figure 1.86. The narrow component at the width of 3-4 ppm is caused by water adsorbed onto a surface of organic crystallites. The broad band (width > 100 ppm) is linked to an ice layer located near the snrface of crystallites. This ice is characterized by middle mobility of the water molecules (between the mobility of molecules... 

The fluorescence properties of tryptophan residues in protein can be considered as three discrete spectral classes One is the bvuied in nonpolar regions of the protein, the fluorescence maximum position appears at 310 330 nm and spectral band width is around 48 49 nm two is located at the surface of protein and completely exposed to water, maximum peak is in 350 353 run and half bandwidth is in the range of 59 61 run the latter is in limited contact with water which is probably immobilized by bonding at the macromolecular surface, the fluorescence maximum peak is located at 340 342 nm and the half bandwidth is about 53 55 nm. 

The greatest use of PVDF is as a source of pressure. The fact that PVDF has an acoustic impedance that is close to that of water or the human body makes it especially suitable as a source of pressure in underwater technology and medicine. PVDF also has an extreme band width, i.e., a large frequency range. 

The plane of fracture is approximately vertical and is clearly visible from the interior of the access tunnel as a band of water-bearing fractured rock with a nominal width of Im. The tunnel intersects the vertical plane of the fracture perpendicularly at a distance 513 m from the tunnel mouth. 

The differences in the NMR spectra measured under Fourier Transform conditions with scalar decoupling of the same substance, say water and ice, boggle the mind. The proton NMR spectrum of the water is sharp and narrow with a band width of one Hz, while the proton NMR spectrum of ice is extremely broad with a band width of 20 KHz. This is totally unexpected. In the early days of experimental NMR, the NMR lines of solids were so broad that no measurable signal could be obtained related to chemical structure. 

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