Rhodamine B dye

Rotational dynamics of a fluorescent dye adsorbed at the interface provides useful information concerning the rigidity of the microenvironment of liquid-liquid interfaee in terms of the interfacial viscosity. The rotational relaxation time of the rhodamine B dye was studied by time-resolved total internal reflection fluorescent anisotropy. In-plane... 

The interactions of the dye acceptors to polymers could also be witnessed in the case of solid films. In this case, the sterically more restrictive cavities of the polymeric film 46 allowed better orbital interaction with the smaller and more flexible rhodamine B dye, and accordingly higher energy transfer with rhodamine B-labeled streptavidin was observed compared to Texas Red-... 

Figure 13.14 Laser-induced fluorescence detection of 100 nM Rhodamine B dye after extraction on the packed bed. The peak marked with the was an unidentified system peak. (Reprinted in part with permission from [46]. Copyright 2005 American Chemical Society.)...

Helical polysilanes where the side groups are partly substituted with Rhodamine B dye molecules and chiral groups (Fig. 12) have been synthesized and spread onto quartz plates by vertical dipping.77 A weak absorption peak due to the dye is observed around 2 eV in addition to the sharp exciton peak at 3.85 eV. The PL spectrum shows a new peak at 2 eV, while the original peak at 4 eV for the polysilane without the dye is greatly decreased. Strong red PL is observed. The introduction of only a few percent of dye modifies the absorption... 

As earlier reported for electrochemical sensing, often the active chromo-phore will be dispersed in a polymeric matrix. For example, Mohr and Wolfbeis reported a nitrate sensor [121] where the active chromophore is a rhodamine B dye which had been modified with an octadecyl side chain to render it hydrophobic and prevent leaching. The dye was dispersed in a plasticised PVC membrane containing a hydrophobic anion carrier (tridodecylmethylammo-nium chloride). On exposure to nitrate, the fluorescence of the dye increased. This membrane, however, only displayed Hofmeister-type selectivity and was also affected by pH. Replacing the quaternary ammonium anion carrier with a palladium phospine chloride carrier led to selectivity for nitrite [ 122], probably due to a preferential interaction between Pd and nitrite ion. 

This inorganic azide has been investigated as a constituent of a binary explosive. The impact sensitivity data obtained using the Picatinny Arsenal apparatus (Figure 9) include that for barium azide made with 1-2% rhodamine B dye. 

Fig. 8 Rhodamine B dye (RhB, red solution) diffusing across a membrane of crosslinked nanoparticles (dotted line). The bold arrows point to the interface in each tube. The two right-hand images represent a time frame of about 15 min. Subsequent addition of water to the RhB/water droplet replaces the CdSe/toluene solution leading to a RhB/water-water interface separated by the nanoparticle membrane. Reprinted with permission from Journal of the American Chemical Society [47]. Copyright (2003) American Chemical Society...

Figure 17-9. Schematic cross-seaion of a composite hexalayer membrane with an arachidic acid and a valinomycin tetralayer covered with an arachidic acid and Rhodamine B dye bilayer (from (771).

Filter standards used for calibration and method assessment were prepared by adding 2 pL drops of standard solutions with concentration of 0-100 mg L onto blank filters. The solutions were prepared in 100 mL acid washed flasks by dilution of a multi-element standard (Merck CertiPUR, 1,000 mg L ) in 18 MQ cm water obtain from a Milli-Q Gradient system (Milhpore, Bedford, MA) with 7 mL eoneentrated nitric acid (65% HNO3, suprapure grade) and 2 mL of a Rhodamine B dye solution (prepared by dissolution of 0.125 g Rhodamine B... 

R. L. Bell [AIChE 18, 495 (1972)] investigated residence time distributions on commercial-scale distillation trays using a fiber optic technique. A pulse of a 10-g/L solution of Rhodamine-B dye was injected into the downcomer of the top tray. The response data are summarized below. 

Experimental Technique and Image Anaiysis Rhodamine B dye is one of a class of fluorescent dyes whose quantum yield is strongly dependent on temperature. Therefore, the... 

Fluorescence is excited by laser (e.g. argon), and the back-scattered fluorescent light picked up by the fibre and analysed by spectrometry and photon-counting techniques. Where a single fibre is used to carry both the exciting and fluorescent light, the natural fluorescence in the fibre can limit the lower detection limit (3 x 10 ) for Rhodamine B dye detected by a 600/im polymer-clad silica fibre (33). This can be overcome using two separate fibres. 

Rotational dynamics of a fluorescent dye adsorbed at the interface provides useful information concerning the rigidity of the microenvironment of liquid-liquid interface in terms of the interfacial viscosity. The rotational relaxation time of the rhodamine B dye was studied by the time-resolved total internal reflection fluorescent anisotropy. In-plane rotational relaxation time of octadecylrhodamine B cation was evaluated under the presence or absence of a surfactant [26]. Table 2.8 shows that by adding a surfactant, the relaxation time and the interfadal viscosity increased. Anionic surfactants SDS and HDHP (hydrogen dihexadecylphosphate) were more effective in reducing the rotational motion, because of the electrostatic interaction. HDHP with double long chains hindered the interfacial rotation more [40]. 

Figure 11.21 Fluorescence intensity versus temperature of Rhodamine B dye at different dye concentrations...

The dye that was used until recently, Rhodamine B dye, was found to contain high levels of chlorides. The chloride content was attributed to pitting detected in the L-Reactor probe pots. The use of this dye was discontinued in 1989. The substitute dye has a very low level of chloride content that is within the acceptance standards. This action is expected to reduce the rate of corrosion significantly. Augmenting the above change, additional pH and impurity controls, QA limits, and improved mixing techniques have been introduced as upgrade measures. 

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