Sodium octylsulfate

Wakabayashi et al. [51] determined penicillamine in serum by HPLC. Serum (0.1 mL) was vortex-mixed for 30 s with 50 pL of 0.1% EDTA and 0.2 mL of 10% TCA. The solution was centrifuged at 1500 x g and filtered. A 5 pL portion was analyzed on a Shodex C18 column (15 cm x 4.6 mm i.d.), using a mobile phase of 19 1 methanolic 0.05 M phosphate buffer (pH 2.8) containing 1 mM sodium octylsulfate and 10 pM EDTA. Liver or kidney samples were similarly extracted, and the extracts were cleaned up on a Bond-Elut cartridge prior to HPLC analysis. Detection was effected with an Eicom WE-3G graphite electrode maintained at +0.9 V versus Ag/AgCl. The calibration graph was linear up to 500 ng, and the detection limits were 20 pg. For 1 pg of penicillamine added to serum, liver, or kidney, the respective relative standard deviations (n = 5) were 3.6, 5.1, and 4.4%. 

Hong et al. applied capillary EKC with dodecyltrimethylammonium-bromide/sodium dodecylsulfate (12.7/21.1 mM) vesicles to the separation of alkylphenones (Fig. 8A) and obtained better resolution than with sodium dodecylsulfate micelles (59). The logarithms of the retention factors for 20 neutral compounds of similar structures showed an excellent linear correlation with log Poct (R2 = 0.98). Similarly, Razak et al. (60) showed that the log capacity factors for interaction between neutral and positively charged analytes and cetyltrimethylammoniumbromide/sodium octylsulfate vesicles correlated linearly with the log Poa values. 

The identification and characterisation of these nanoband-like image patterns is the aim of the present work. Thus, we investigate the occurrence of such nanobands in an Mg-Al-CCh-LDH adsorbed with sodium octylsulfate (SOS), sodium octyl- and dodecylbenzenesulfonate (SOBS and SDBS, respectively). Energy Dispersion Spectroscopy (EDS) was also used to analyse the nanobands observed for the SDS-adsorbed LDH. The influence of thermal treatment, washing with water, and the deposition process on the occurrence of nanobands were also studied. 

Fig. 2.17. Plots of 23Na+ NMR chemical shifts versus the inverse concentration of sodium octanoate ( ), sodium octylsulfate (o), sodium octylsufonate ( ) and sodium dodecylsulfate (X). A positive shift is upfield. (From Ref.57))...

In our laboratories, extensive use has been made of vapor pressure (14-18) and membrane methods ( 2, 3, 19, 20) to Infer thermodynamic results for ternary aqueous systems containing an ionic or a nonionic surfactant and an organic solute. The most precise solubilization measurements ever reported have been obtained with an automated vapor pressure apparatus for volatile hydrocarbon solutes such as cyclohexane and benzene, dissolved In aqueous solutions of sodium octylsulfate and other Ionic surfactants (15, 16). A manual vapor pressure apparatus has been employed to obtain somewhat less precise results for solutes of lower volatility (17, 18). Recently, semi-equilibrium dialysis (19, 20) and MEUF (2) methods have been used to investigate solute-surfactant systems in which the organic solubilizates are too involatile to study by ordinary vapor pressure methods. 

The p-nitrocatechol formed was separated at 30°C with a reversed-phase Cjg column (4 millimeters X 125 mm) from EM Science. The mobile phase was prepared by mixing 13 g of monochloroacetic add, 4.99 g of NaOH, 0.177 g of sodium octylsulfate, 130 mL of acetonitrile, 10 mL of tetrahydrofu-ran, and approximately 620 of mL water. After the pH had been adjusted to 3.3 with approximately 220 mL of 8 M acetic acid, the mixture was diluted to 1 liter with water. The electrochemical detector was set at an applied potential of 0.750 V. 

Radiolabeled products were separated from substrates by chromatography on a Merck Qg column (5 /an). The mobile phase contained 0.1 M sodium acetate, 0.1 M citric acid, 0.1 mAf sodium octylsulfate, 0.15 mAf EDTA, and 0.2 mAf dibutylamine in 10% methanol (v/v). The pH was 4 for the monoamine oxidase assay and 3.7 for phenol sulfotransferase. A flow-through radioisotope detector was used to quantitate the amount of radioactivity in the eluted peaks. 

The substrates and products just noted were separated on an Ultrasphere I.P. CI8 column (4.6 mm x 250 mm, 5 /tm). The mobile phase contained 75 mAf sodium phosphate (pH 2.75), 1 mM sodium octylsulfate, 500 fiM EDTA, and 13% (v/v) acetonitrile. Quantitation was by electrochemical detection of the products using 0.75 V versus an Ag/AgCl reference electrode. 

Due to the high polarity of these compounds, their retention is very small when the usual methanol/water-mixtures are used. The retention is markedly increased by coating the phase with an anionic surfactant. A good resolution of all three compounds within an acceptable total analysis time is obtained with sodium octylsulfate and methanol in sulfuric acid solution. Mikropak MCH-10 (Varian Co.) is suited as the stationary phase, for example, with a particle diameter of 10 pm. Fig. 5-56 shows the corresponding chromatogram of a standard with a baseline-resolved separation of all three components. 

Conditions T he drugs are extracted from biological materials by an ion pair extraction with sodium octylsulfate as counter ion at pH 3.0. The extracts are injected onto a reversed-phase system with a cyano column as stationary phase. MeCN - phosphate buffer pH 3.0 (65 35). 

Morphine, dilaudid, naloxone, and naltrexone were extracted from urine and separated on a C g column (electrochemical detector at -1-0.85 V vs. Ag/AgCI) using a 10/90 IPAAvater (0.1 M ammonium phosphate at pH 4.5 with 0.02% sodium octylsulfate) mobile phase [539]. Baseline resolution was obtained. Mote positive potentials (e.g., +0.95 V) lead to increased sensitivity but faster poisoning of the electrode. A linear response range from 50 to 5000 ng was obtained. 

Selenols (RSeH), diselenides (RSe-SeR) and selenyl sulfides (/ 5-SeR) were separated on a Cig column (electrochemical detector at — MOV vs. Ag/AgCl). A 5/95 acetonitrile/water (5mM phosphate buffer at pH 2.9 with 40mg/L sodium octylsulfate) mobile phase was used [920]. A plot of k versus percent acetonitrile for five such compounds was presented for the range of 1-8%. The k values varied from 4-50 at 1% acetonitrile to <0.2-4 at 8% acetonitrile. Selectivity of detection was achieved by setting the potential to -0.55 V (for diselenides and selenyl sulfides) or +0.15 V (for selenols only). 

Fig. 6-58. Separation of iminodiacetic acid, ethylenediaminetriacetic acid, and ethylenediaminediacetic acid. - Separator column Mikropak MCH-10 (Varian) eluant 0.2 g/L sodium octylsulfate + 0.5 mL/L H2SO4 / methanol (92 8 v/v) flow rate 1 mL/min detection UV (215 nm) injection volume 50 pL solute concentrations 500 mg/L iDA (1), 50 mg/L EDTriA (2), and 50 mg/L EDDA...

Fig. 5.15 presents the results obtained for sodium octylsulfate. This surfactant has a high cmc (as 0.135M). The agreement between the theory and experiment [57] is satisfactory below the cmc. Above the cmc, experimental and calculated values deviate rapidly. Finally Fig. 5.16 presents the results obtained for sodium octanoate as a function of total monomer concentration. The cmc is very high ( i 0.4M) and there is also a divergence between experiment and theory above the cmc. There is one fitting parameter the charge of the micelle. 

Figure 5.15 Conductance of sodium octylsulfate as a function of total monomer concentration (cmc — 0.135 mol/L). ( ) experimental data (from reference [57]). 1 Ideal case, 2 Limiting law (Onsager), 3 Theoretical results ( MSA). Parameters = 7.8 10 m s (obtained through a fitting procedure), = 1.333...

Conductance of sodium octylsulfate as a function of total monomer... 

There have been few investigations of the effect of aromatic or alkyl solubilizates on the micellar dynamics. Alkanes have been found to have almost no effect on the value of the relaxation time for the surfactant exchange in micellar solutions of sodium heptylsulfate and hexylammonium chloride. Likewise, cyclohexane has very little effect on the exchange in micellar solutions of sodium octylsulfate. In these studies the amount of solubilizate was relatively small. In contrast. 

The first study mainly involved mixed solutions of PVP or poly(vinyl alcohol) and sodium octylsulfate. No information on the binding stoichiometry and on the aggregation number... 

Hatton et al. have also reported on the aggregation of cationic/anionic surfactant mixtures to form vesicles. The systems studied were SOS/CTAB, SDS/DTAB, HDBS/CTAB (DTAB and CTAB = dodecyl and hexadecyl tri-methylammonium bromide SOS = sodium octylsulfate HDBS = dodecylbenzenesulfonic acid). The transition to stable vesicles is rather slow for the SOS/CTAB and SDS/DTAB systems and complex with the observation of three relaxation processes with relaxation times of about 10, 100, and 2000 s in addition to a very fast process (< 4 ms, the dead time of... 

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