Triton, adsorption

Surface heterogeneity may be inferred from emission studies such as those studies by de Schrijver and co-workers on P and on R adsorbed on clay minerals [197,198]. In the case of adsorbed pyrene and its derivatives, there is considerable evidence for surface mobility (on clays, metal oxides, sulfides), as from the work of Thomas [199], de Mayo and co-workers [200], Singer [201] and Stahlberg et al. [202]. There has also been evidence for ground-state bimolecular association of adsorbed pyrene [66,203]. The sensitivity of pyrene to the polarity of its environment allows its use as a probe of surface polarity [204,205]. Pyrene or ofter emitters may be used as probes to study the structure of an adsorbate film, as in the case of Triton X-100 on silica [206], sodium dodecyl sulfate at the alumina surface [207] and hexadecyltrimethylammonium chloride adsorbed onto silver electrodes from water and dimethylformamide [208]. In all cases progressive structural changes were concluded to occur with increasing surfactant adsorption. 

SG sols were synthesized by hydrolysis of tetraethyloxysilane in the presence of polyelectrolyte and surfactant. Poly (vinylsulfonic acid) (PVSA) or poly (styrenesulfonic acid) (PSSA) were used as cation exchangers, Tween-20 or Triton X-100 were used as non- ionic surfactants. Obtained sol was dropped onto the surface of glass slide and dried over night. Template extraction from the composite film was performed in water- ethanol medium. The ion-exchange properties of the films were studied spectrophotometrically using adsorption of cationic dye Rhodamine 6G or Fe(Phen) and potentiometrically by sorption of protons. 

Figure 26 shows the redox potential of 40 monolayers of cytochrome P450scc on ITO glass plate in 0.1 KCl containing 10 mM phosphate buffer. It can be seen that when the cholesterol dissolved in X-triton 100 was added 50 pi at a time, the redox peaks were well distinguishable, and the cathodic peak at -90 mV was developed in addition to the anodic peak at 16 mV. When the potential was scanned from 400 to 400 mV, there could have been reaction of cholesterol. It is possible that the electrochemical process donated electrons to the cytochrome P450scc that reacted with the cholesterol. The kinetics of adsorption and the reduction process could have been the ion-diffusion-controlled process. 

Effectiveness of selective adsorption of phenanthrene in Triton X-100 solution depends on surface area, pore size distribution, and surface chemical properties of adsorbents. Since the micellar structure is not rigid, the monomer enters the pores and is adsorbed on the internal surfaces. The size of a monomer of Triton X-100 (27 A) is larger than phenanthrene (11.8 A) [4]. Therefore, only phenanthrene enters micropores with width between 11.8 A and 27 A. Table 1 shows that the area only for phenanthrene adsorption is the highest for 20 40 mesh. From XPS results, the carbon content on the surfaces was increased with decreasing particle size. Thus, 20 40 mesh activated carbon is more beneficial for selective adsorption of phenanthrene compared to Triton X-100. 

L 4 12 mesh, M 12-20 mesh, S 20-40 mesh. Amt total surface area, Aext external surface area, Aphe surface area for phenanthrene adsorption, Atx surface area for Triton X-100 adsorption... 

The adsorption isotherms for each chemical, Triton X-100 or phenanthrene, on the activated carbons were shown in Figs. 1 and 2. The adsorption isotherms are expressed as qg [g g ], the amount of compounds adsorbed per unit mass of adsorbent, as a fimction of Q [g l ], the concentration in solution at equilibrium [5, 6]. The best-fit parameters for Freimdlich isotherms (g = or linear isotherms (q - Kj C ) were summarized in Table 2. The... 

Phenanthrene dissolved in Triton X-100 solution was separated by sorption with three GACs with different particle size (4 12,12 20, and 20 40 mesh). The highest adsorption selectivity was obtained with the 20 40 mesh over a wide concentration range of phenanthrene and Triton X-100. The results demonstrate that the selective adsorption is potentially effective to reuse surfactants in a soil-washing process for the remediation of contaminated soils. 

Capillary wall Generally, the most straightforward approach is to use an uncoated fused silica capillary. But sometimes this is not possible because of adsorption problems to the capillary wall, or other wall properties are needed to control the electroosmotic flow. In literature, there are multiple examples. Besides permanently coated capillaries, there are several descriptions of dynamic coatings available, e.g., triethanolamine, Triton X-100, Polybrene, and quaternary ammonium salts. The advantage of these dynamic coatings is that the coating can be renewed between injections, which could improve repeatability and reproducibility of the separation. 

Reconstruction of Au(lll) is observed in STM images as double rows separated from each other by 6.3 nm [335]. Some model calculations have been performed [362] to show that the energy difference of the reconstructed and unreconstructed Au(lll) is small. The effect of Triton X-100 on the reconstruction process of Au(lll) surface has been studied in chloride media [363] applying CV and double potential-step chronocoulometry. It has been found that adsorption of Triton X-100 stabilizes the reconstructed face of Au(lll). Hobara etal. [364] have used in situ STM to study reconstruction of Au(lll), following reductive desorption of 2-mercaptoethanesulfonic acid SAMs. 

Precautions should also be taken with the aqueous solvents used to prepare standard working solutions in order to avoid adsorption problems, especially at low concentrations. To minimize adsorption during standard curve and validation sample (VS)/QC preparations, aliquots of the high-concentration stock solutions should be spiked promptly into the control blank plasma to prepare the standards and VS/QC. Once the compounds are in an environment of protein solutions, the adsorption problem is negligible. If there is a problem, however, adding or pre-rinsing with a solution of protein or a chaotropic agent (e. g., Tween, Triton X-100 or CHAPS) may help to alleviate the problem. 

The widely accepted opinion, which supposes that not only an adsorption at the quartz particle but also an interaction with the cell membrane occurs, may have been the reason for Fermtti and co-workers (29) to study the effect of such polymeric N-oxides on the cancer metastasis. Previously it has been shown by Franchi and coworkers (30), that polymeric detergents of the Triton type [5] show strong metastases stunting activity. 

Much of the early studies of surfactant adsorption at the solid-solution interface were based on classical experimental techniques, such as solution depletion [1, 32], fluorescence spectroscopy [2], and measurements of the differential enthalpy of adsorption [2], Such methods have provided much of the basic initial understanding. However, they provide no direct structural information and are difficult to apply to mixtures [23, 34], However, when combined with other techniques, such as NMR and flow microcalorimetry, they provide some insight into the behaviour of mixtures. This was demonstrated by Thibaut et al. [33] on SDS/C10E5 mixtures adsorbed onto silica and by Colombie et al. [34] on the adsorption of SLS/Triton X-405 mixtures onto polystyrene particles. 

The infrared spectrum of the precipitated polystyrene at this stage exhibited no absorption using thermally polymerized polystyrene in the reference beam. A 3.5% solution of dried Triton X-405 in chloroform showed intense adsorption at about 1100 cm. 1, characteristic of the ether linkage. 

This instability can be avoided by adding a non-ionic surfactant to the surface of the latex, forming a hydrophilic layer (Triton x-405 of 30 units) on the surface of the latex [22]. In addition, this compound reduces the stacking effect by masking the hydrophobic domains (or properties) of the surface. Indeed, competition for adsorption between the ODN and the surfactant molecules can also lead to desorption. However, this effect was not observed in all reported studies, but it is in principle accessible by comparing the adsorption energies of ODN and the surfactant on the surface of the latex. 

Fig. 8. Residual adsorbed amount of dT35 onto bare latex particles as a function of ionic strength. Adsorption was performed onto bare latex particles with Ns=1.0 mg nr2 at pH 5 and 10 2 mol/1 ionic strength. The desorption was carried out after two washes using buffer (at various ionic strengths, pH 10 and 1% Triton x-405) [22]...

A more common situation is the effect of adsorption on the stability of a suspension. This may be favourable (by modifying, for example, the surface charge of the particles, or by increasing the distance between particles) or unfavourable. Such an example of the latter effect was found with non-ionic surfactant Triton TX-100 and silica suspensions. It was found that the adsorption produced micelle-like aggregates which underwent flocculation by a bridging mechanism (Giordano-Palmino et al.,... 

Desalting techniques include ultrafiltration, which simultaneously desalts and concentrates the sample membrane dialysis (Cooksy, 1992) and simple dilution in low ionic strength buffer or water. The latter method is especially useful when glycerol, Triton X-100, or formamide has been added to the PCR mixture. It should be noted that loss of DNA from adsorption onto the filters in ultrafiltration has been reported (Butler et al., 1994). Thus, as a rule, sample desalting by this method should be used as a last resort. 

A characteristic property of surfactant molecules is their tendeney to aggregate at interfaces. Examples are adsorptions onto solids and monolayer formation at an air-water interface. Surfactants sometimes ereate their own interface by forming very small aggregates like mieelles or vesieles to remove a portion of their structure from direct contact with a solvent. In ease of a mieelle formed with a surfactant such as Triton X-IOO, the hydroearbon ehains are in closer contact in the center and form a hydrophobic microenvironment. The ethylene oxide moieties are exposed to water with mueh greater frequeney. If a hydrophobic species is added into this micellar system, there will be a tendeney for the hydrophobic molecules to be concentrated inside a mieelle. At low concentration, the micelle system and the added hydrophobic additives ean reach a thermodynamic equilibrium, which is often called microemulsion system. At high concentration, the hydrophobic additives form their own separate phase and the surfactant molecules serve only as a decorative layer... 

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