8-Anilino-l-naphthalenesulfonic acid ANS

In competitive homogeneous immunoassay, separation and quantitation of free and bound labeled antigen (cortisol) were carried out in a fused silica chip. Since the antibody-antigen complex was not detected, an internal standard (fluorescein) was added to aid quantitation. In addition, since most of the total cortisol was bound in the serum, a releasing agent, 8-anilino-l-naphthalenesulfonic acid (ANS), should be added [1006]. In other reports, competitive immunoassay for BSA was demonstrated after performing a CE separation on-chip [105,1005]. 

Yamaguchi et al. used poly(NIPAM-co-CD) 4 as a thennosensitive polymer bearing P-CD and 8-anilino-l-naphthalenesulfonic acid (ANS) as a guest molecule (Figure 5.8). The LCST of poly(NIPAM-co-CD) in an aqueous solution was higher... 

Siano and coworkers [14] report the use of 8-anilino-l-naphthalenesulfonic acid (ANS) as a probe of environment polarity in polyacrylamides containing 1 mole percent n-dodecylacrylamide (estimated from feed ratio) in 2 wt% NaCl. ANS, an amphoteric probe is selectively solubilized at the water-hydrophobe interface. The fluorescence emission maximum is shifted from 520 nm, in aqueous environments to approximately 462 nm in hydrophobic environments [18]. Studies of the polymer described above and a homopolymer of acrylamide were accomplished by varying polymer concentration up to 5000 ppm at constant ANS concentration. In Fig. 2.10 a, a plot of the emission wavelength maximum of ANS vs polymer concentration indicated an increasingly hydro-phobic environment with increasing copolymer concentration. Above approximately 1000 ppm, emission wavelength remained constant, indicating that ANS... 

Sodium measurements use three components for the reagent phase [73] an ionophore selective for Na immobilized on silica, an anionic fluorophore (F), the ammonium salt of 8-anilino-l-naphthalenesulfonic acid and a cationic polyelectrolyte (P), copper(II)-poly-... 

In two-phase systems, however, where surfactant and water can partition between a fluid and a liquid phase, significant pressure effects occur. These effects were studied for AOT in ethane and propane by means of the absorption probe pyridine N-oxide and a fluorescence probe, ANS (8-anilino-l-naphthalenesulfonic acid) [20]. The UV absorbance of pyridine A-oxide is related to the interior polarity of reverse micelles, whereas the fluorescence behavior of ANS is an indicator of the freedom of motion of water molecules within reverse micelle water pools. In contrast to the blue-shift behavior of pyridine N-oxide, the emission maximum of ANS increases ( red shift ) as polarity and water motion around the molecule increase. At low pressures the interior polarity, degree of water motion, and absorbance intensity are all low for AOT reverse micelles in the fluid phase because only small amounts of surfactant and water are in solution. As pressure increases, polarity, intensity, and water motion all increase rapidly as large amounts of surfactant and water partition to the fluid phase. The data indicate that the surfactant partitions ahead of the water thus there is a constant increase in size and fluidity of the reverse micelle water pools up to the one-phase point. An example of such behavior is shown in Fig. 4 for AOT in propane with a total fVo of 40. The change in the ANS emission maximum suggests a continuous increase in water mobility, which is due to increasing fVo in the propane phase, up to the one-phase point at 200 bar. 

Materials. The synthesis of the p-CD adsorbate is described in references 12, 13, and 14. 6-ferrocenyl-hexanethiol (Fc) was synthesized according to the literature [15] 8-anilino-l-naphthalenesulfonic acid (1,8-ANS), 2-hydroxy-ethanethiol, and octadecanethiol were purchased from Aldrich and used as received. 

Abbreviations. aT = a-tocopherol, AC = aminocoumarin, ANS = l-anilino-8-naphthalenesulfonic acid, CTAB = cetyltrimethylammonium bromide, DPPC = dipalmitoylphosphatidylcholine, DPPH — l,l-diphenyl-2-picrylhydrazyl, DSHA = Ai-dansylhexadecylamine, GMO = glycerol monooleate, HC = hydrocoumarin, N,N -DOC = JV,JV -di(octadecyl)oxacarbocyanine, PC = phosphatidylcholine, p-CUO = pyrene caroboxaldehyde, SDES — sodium decyl sulfate, SDS — sodium dodecyl sulfate, STS = sodium tetradecyl sulfate. 

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