Cetyltrimethylammonium Ion Research Articles

Examination of metallochromic indicators and water-soluble reagents for metals by planar electrophoresis

Water-soluble azo, phthalein, sulphonphthalein and anthraquinone indicators and reagents were subjected to low-voltage electrophoresis on cellulose acetate sheets at pH 2–12. All dyes except low-sulphonated azo dyes yielded one or more sharp bands showing good mobility and resolution over some range of pH values. The performance exceeded that of other possible planar electrophoresis media. The addition of copper, lanthanum, cetyltrimethylammonium or lauryl sulphate ions caused a marked and often beneficial change in behaviour.

Effect of a phenyl group in quaternary ammonium compounds on thiamine uptake in isolated rat hepatocytes

The inhibitory effect of a phenyl group in quaternary ammonium compounds on thiamine uptake in isolated rat hepatocytes was investigated. The phenyltrimethylammonium ion was a more potent inhibitor than the tetramethylammonium ion, while the dibenzyldimethylammonium ion was the most potent inhibitor of thiamine uptake among those compounds examined. A kinetic study showed that this compound was a competitive inhibitor. The cetyltrimethylammonium ion was a less effective inhibitor than the benzyltrimethylammonium ion, and the palmitoylcholine ion was a weak inhibitor. These results indicate that the lipophilicity of a quaternary ammonium compound is not always correlated with its affinity for thiamine-carrier binding, but the presence of a phenyl group plays a significant role in affinity. The inhibitory effect of the series of (CH 3) 3N +(CH 2) n C 6H 5 ( n = 0−6) compounds on thiamine uptake in isolated rat hepatocytes was studied. The maximal inhibitory activity occurred at n = 5. These results suggest that the phenyl group in a quaternary ammonium compound has a specific interaction with the thiamine-binding site in rat liver plasma membrane.

Expression of a plasmid borne ethidium resistance determinant fromStaphylococcusinEscherichiacoli: Evidence for an efflux system

A 1.1-kilobase (kb) DNA fragment derived from a staphylococcal plasmid specifying resistance to ethidium has been cloned into plasmid vector pUC9 in Escherichia coli. This fragment conferred resistant to ethidium and also to cetyltrimethyl ammonium ion in this host. Studies with labelled ethidium indicated that the basis of resistance was extrusion from the cell by an efflux system.

Determination of quaternary ammonium ion as the precipitate with tetrathiocyanatocobaltate(II) by densitometry

A simple and rapid method for the determination of quaternary ammonium ions (Q+) has been developed. The method is based on the formation of the blue precipitate of Q2[Co(SCN)4] by treating Q+ with cobalt(II) and thiocyanate, collection of the precipitate on a membrane filter and measurement of the reflecting absorbance of the resulting thin layer of precipitate. Zephiramine, cetyltrimethylammonium, tetradecyl-trimethylammonium, dodecyltrimethylammonium, tetrapentylammonium and tetrabutylammonium ions can also be determined. In addition a non-ionic surfactant, Triton X-100, can be determined in the presence of strontium chloride.

The determination of free long-chain quaternary ammonium species with an ion-selective electrode based on a cetyltrimethylammonium ion pair

The cetyitrimethylammonium ion-selective electrode described is based on a tetrazole ion-pair and silicone-rubber membranes. The electrode is almost Nernstian in response from 10 -6 M to the critical micelle concentration. The electrode responds little to dodecyland decyltrimethylammonium ions and inorganic ions. Selectivity coefficients for numerous compounds are given. The uses of the ion-selective electrode are discussed in terms of the ability to monitor free quaternary ammonium ions in the presence of electrolyte and complexing additives. The electrode described can be useful in developing certain pharmaceutical formulations.

Ion-exchange phenomena and concomitant pH shifts on the equilibration of reversed-phase packings with ion-pairing reagents

Breakthrough patterns of eluents containing tetrabutylammonium or cetyltrimethylammonium ions (two frequently used ion-pairing agents in high-performance liquid chromatography) have been studied, using reversed-phase columns with octadecyl chains permanently bonded to 10-μm silica particles. The occurrence of pH shifts either before or after the breakthrough of the ion-pairing agents has been demonstrated. An explanation for the breakthrough patterns is offered and evidence for two different binding mechanisms of these agents is presented.

Spectrophotometric determination of aluminium and gallium with pyrogallol red and cetyltrimethylammonium ions

Spectrophotometric methods are described for the determination of microgram amounts of aluminium and gallium based on the formation of a ternary complex between the metal, pyrogallol red, and cetyltrimethylammonium bromide. The complexes have absorbance maxima at 610 and 615 nm, respectively, with molar absorptivities of 4.8 × 10 4(Al)and 1.0 × 10 5 liter mol −1 cm −1 (Ga). Numerous metals interfere. Gallium can be separated by extraction of gallium from 7 M hydrochloric acid with di-isopropyl ether. However, aluminium can be separated by extraction of interfering ions with cupferron.

A quantitative treatment of micellar effects upon deprotonation equilibriums

The apparent base dissociation constants, KB, for deprotonation of benzimidazole in dilute NaOh go through minima with increasing concentration of cetyltrimethylammonium ion surfactants (CTAX, X = Cl, Br, NO/sub 3/) at concentrations of surfactant counterions is maintained at 0.1 mole. In both cases the micellar effect on KB follows the sequence CTaCl > CTaBr > CTaNO/sub 3/. These observations are consistent with a pseudophase ion-exchange model in which the micelle binds OH/sup -/ and both forms of the indicator, increasing deprotonation and decreasing KB, but the counterion of the surfactant displaces OH/sup -/ from the micellar surface so that KB goes through a minimum with increasing (CTAX). This model leads to a simple quantitative treatment which fits the data for (CTAX) > 0.01 mole. A similar pattern of behavior has been found for deprotonation of phenols and oximes in CTABr in the presence of borate buffer. Intrinsic basicity constants in the micellar pseudophase can be estimated which are larger than those in water by approximately one order of magnitude. 39 references.

Sensitive spectrophotometric determination of molybdenum(VI) with Pyrogallol Red and cetyltrimethylammonium ions

Pyrogallol red in the presence of cetyltrimethylammonium bromide is proposed for the spectrophotometric determination of microgram amounts of molybdenum. The sensitivity of the color reaction between molybdenum and Pyrogallol Red has been greatly increased by the sensitizing action of cetyltrimethylammonium bromide ( ϵ 600 nm = 90,000). Beer's law is obeyed over the range 0.1–0.4 μg/ml of molybdenum. The composition of the complex may therefore be formulated as Mo:PR:CTA = 1:2:4.

Sensitive spectrophotometric determination of gallium with eriochrome Cyanine R and cetyltrimethylammonium ions

A new sensitive, spectrophotometric determination of gallium, based on the ternary gallium-Eriochrome Cyanine R-cetyltrimethylammonium system has been developed. Atλ max=588 nm the molar absorptivity is 1.20×105l·mole−1·cm−1. The maximum absorbance is attained in 5 min in the presence of a 10-fold molar ratio of Eriochrome Cyanine R and an approx. 50-fold ratio of cetyltrimethylammonium bromide (to Ga). Citrate, EDTA and to a lesser extent tartrate, interfere. Interference by metals can be eliminated by a preliminary extraction of gallium with di-isopropyl ether from 7 M hydrochloric acid in the presence of ascorbic acid as reductant. The results for gallium (at a concentration level of 1×10−4%) in aluminium metal and chloride indicate good precision and accuracy.

Spectroscopic Investigations of Viscoelastic Solutions Containing the Cetyltrimethylammonium Ion

AbstractIt has previously been shown [1] that very dilute solutions of cetyltrimethylammonium salts can show strong viscoelastic behaviour. In order to elucidate the molecular organization specific for the viscoelastic behaviour we have, using several spectroscopic techniques, investigated aqueous solutions containing cetyltrimethylammonium salicylate.Using proton magnetic resonance it is found by simulation of the bandshapes [2] that in these dilute (<1 %) micellar solutions the viscoelastic behaviour correlates with the aggregate size, both with respect to changes in composition and in temperature. Thus a necessary condition for viscoelastic behaviour is aggregates larger than the minimal spherical micelle.The viscoelastic solutions were oriented by Couette flow. The orientation was monitored through the linear dichroism (LD) of the solution and it is found that the LD increases with increasing concentration. The temperature for obtaining zero LD is in agreement with the disappearance of the viscoelastic properties of the solution.An independent measure of aggregate sizes was obtained by studying the quasielastic light scattering (QLS) of the solutions which also indicates a transition from large to smaller aggregates at higher temperatures.It is suggested that electrostatic and anisotropic interactions between the large aggregates cause a specific periodic colloidal structure that is responsible for the viscoelastic behaviour.

Spectroscopic Investigations of Viscoelastic Solutions Containing the Cetyltrimethylammonium Ion

AbstractIt has previously been shown [1] that very dilute solutions of cetyltrimethylammonium salts can show strong viscoelastic behaviour. In order to elucidate the molecular organization specific for the viscoelastic behaviour we have, using several spectroscopic techniques, investigated aqueous solutions containing cetyltrimethylammonium salicylate.Using proton magnetic resonance it is found by simulation of the bandshapes [2] that in these dilute (<1%( micellar solutions the viscoelastic behaviour correlates with the aggregate size, both with respect to changes in composition and in temperature. Thus a necessary condition for viscoelastic behaviour is aggregates larger than the minimal spherical micelle.The viscoelastic solutions were oriented by Couette flow. The orientation was monitored through the linear dichroism (LD) of the solution and it is found that the LD increases with increasing concentration. The temperature for obtaining zero LD is in agreement with the disappearance of the viscoelastic properties of the solution.An independent measure of aggregate sizes was obtained by studying the quasielastic light scattering (QLS) of the solutions which also indicates a transition from large to smaller aggregates at higher temperatures.It is suggested that electrostatic and anisotropic interactions between the large aggregates cause a specific periodic colloidal structure that is responsible for the viscoelastic behaviour.

Sensitive spectrophotometric determination of beryllium with Eriochrome Cyanine R and cetyltrimethylammonium ions

In the presence of cetyltrimethylammonium ions (CTA) a significant bathochromic shift in the color reaction of beryllium with Eriochrome Cyanine R (ER) takes place. This is accompanied by a nearly trifold increase in the sensitivity. The triple complex of beryllium with Eriochrome Cyanine R and CTA (in which the molar ratio of Be:ER is 1:2) is proposed as a basis of a new sensitive spectrophotometric method of beryllium determination. The molar absorptivity ϵ = 8.65 × 10 4 at λ max = 590 nm, pH ~ 7 (borate buffer), when the solution is heated at 60 °C for 15 min. The method is very selective when EDTA is used as a masking agent. EDTA does not affect the formation of the triple beryllium complex neither do tartrate, citrate, and acetate. Phosphate and fluoride interfere.

Characterization of silica surfaces by adsorption from solution. Investigations into the mechanism of adsorption of cationic surfactants

The adsorption of dodecyltrimethylammonium (DTA +) and cetyltrimethylammonium (CTA +) ions together with that of the Br − counterions on two types of silica has been measured as a function of the pH of the aqueous solution. At pH 8 and 9 the DTA + adsorption isotherms show a two-step character. Br − adsorption does not set in before the DTA + adsorption starts to increase to the second plateau. At pH 10, the DTA + adsorption continuously increases to one final plateau value, but again Br − only starts to be adsorbed once a certain minimum concentration is exceeded. For CTA + the isotherms are single-step at all three pH values, but the Br − isotherms are similar to those in the DTA + system. When the aqueous solutions are 1 M in n-butanol, the maximum DTA + adsorption is restricted to the value of the mentioned first plateau, while CTA + adsorption at maximum is also limited to about half the value it reaches in the absence of butanol. In 1 M butanol, Br − adsorption no longer takes place. The adsorption of cationic surfactants has been supplemented by electrophoresis measurements under the various conditions and by determination of the critical micelle concentrations of the two surfactants in aqueous n-butanol solutions. The results support a model proposed by Rupprecht, according to which at low surfactant concentrations a monolayer is formed, due to interaction of opposite charges on the silica surface and the surfactant ions. At higher concentrations a different mechanism (probably hydrophobic bonding) causes a bilayer to be built up. Application of this model allows the number of dissociated and undissociated silanol groups on the silica surface to be determined as a function of the pH. The calculated pK-value for surface silanol groups appears to be somewhat lower than hitherto assumed.

Effects of Magnesium Ions, Adenosine Triphosphate, Palmitoylcarnitine, and Palmitoyl Coenzyme A on Acetyl Coenzyme A Carboxylase

Acetyl coenzyme A carboxylase is activated strongly by incubation with magnesium ions in the absence of citrate and by incubation with citrate in the absence of magnesium ions. The activation by magnesium ions is concentration- and time-dependent. Under optimum conditions the effects of citrate and magnesium ions are not additive. Although the activation by magnesium ions occurs in the absence of citrate, the enzyme requires citrate for the complete reaction. Addition of adenosine triphosphate to the activation medium containing either magnesium ions or citrate or both strongly inhibits the activation of acetyl coenzyme A carboxylase. The inhibition is not due to removal of magnesium ions by chelation with adenosine triphosphate. Enzyme which has been activated with magnesium ions sediments at about the same rate as the inactive enzyme. Palmitoyl carnitine and cetyl trimethylammonium ions also stimulate the activity of the enzyme. This type of activation occurs rapidly, unlike the activation of the rat liver enzyme by magnesium ions and citrate. The maximum degree of stimulation by palmitoyl carnitine is observed when acetyl coenzyme A carboxylase has not been fully activated with other activators, but a 2- to 3-fold stimulation is observed even with enzyme which has been activated optimally with magnesium ions and citrate.

The displacement of calcium ions from phospholipid monolayers by pharmacologically active and other organic bases.

1. The binding of (45)Ca(2+) to a monolayer of phosphatidylinositol at the air-water interface was maximal when the separation of the phospholipid head groups approximated to the diameter of a hydrated Ca(2+) ion. 2. The displacement of Ca(2+) adsorbed on monomolecular films of phosphatidylinositol by a series of drugs (both narcotic and excitatory) and other organic bases was related to the ability of the bases to penetrate into the film. 3. With films of phosphatidylinositol at constant area, and at an initial surface pressure of 10dynes/cm., the displacement of Ca(2+) by increasing concentrations of the local anaesthetic, tetracaine, was linearly related to the change in surface pressure (Deltapi) caused by the penetration of the drug. 4. Deltapi and the displacement of Ca(2+) showed a related fall when the initial surface pressure of the phosphatidylinositol film was increased from 4 to 40dynes/cm. both at a constant bulk tetracaine concentration and when this latter concentration was adjusted to keep it at a constant ratio to the surface density of phosphatidylinositol molecules. 5. The displacement of Ca(2+) from phosphatidylinositol films by cetyltri-methylammonium ions was directly compared with the surface concentration of the base in the film, measured by using labelled base and a surface-radioactivity technique. 6. The ability of a series of straight-chain aliphatic amines to displace Ca(2+) from phosphatidylinositol films increased with the number of carbon atoms up to C(12). However, there was a marked jump in the displacing activity after hexylamine, and this could probably be correlated with the carbon chain's being of sufficient length to just reach the hydrophobic fatty acid chains of the orientated phospholipid molecules with the charges on both substances in juxtaposition.

Studies of protein-polysaccharide complex (proteoglycan) from human nucleus pulposus I. Isolation and preliminary chracterisation

1. 1. The protein-polysaccharide complex (proteoglycan) from human nucleus pulposus was extracted with water. 99% of the hexosamine-containing material was recovered in the extract. 2. 2. The proteoglycans in the extract were precipitated on a cellulose column as a water-insoluble complex with cetyltrimethyl ammonium ion. 3. 3. Contaminating proteins were eluted with cetyltrimethyl ammonium bromide (CTAB) in phosphate buffer at pH 9.0 and CTAB in acetate buffer at pH 4.0. 4. 4. The proteoglycan was finally eluted with 1.25 M MgCl 2. 5. 5. The proteoglycan contained both glucosamine and galactosamine. 6. 6. Attempts to fractionate the material into components containing only one of these sugars were unsuccessful. 7. 7. After digestion with testicular hyaluronidase and subsequent fractionation the ratio of glucosamine to protein was the same as before digestion. 8. 8. These experiments suggest that the two main polysaccharides in the nucleus pulposus are bound to the same protein core.