Sulfonated 4 octane

As the solvent concentration increases, the PIC reagents will interact more strongly with the mobile phase and will be less strongly adsorbed on the reverse phase surface. As a consequence, there will be less ion exchange material on the stationary phase surface. This is clearly demonstrated by the adsorption isotherm of octane sulfonate shown in figure 10. 

The desulfinase enzyme was reported to have narrow substrate specificity. In addition to HBPSi, only 2-phenyl benzene sulfinate was reported to serve as a substrate [164], It was found to be inactive against benzene sulfinate, cysteine sulfinate, benzene sulfonate, /7-toluene sulfonate, 1-octane sulfonate, methane sulfonate, and taurine. This enzyme was found to be inhibited by HBP beginning at 0.5 mM with complete loss of activity at 9 mM HBP, but was not affected by sulfite. 

Column, octadecyl-bonded silica gel, 15 cm x 4.6 mm i.d. eluent, 0.01 M sodium acetate buffer containing 0.4 M copper acetate and 1.0 mM sodium alkanesulfonate (pH 5.6) flow rate, 1 ml min-1 detection, UV 230 nm. Counter-ion C6, sodium hexanesulfonate Cl, sodium heptanesulfonate and C8, sodium octane sulfonate. Compounds Ser, serine Gly, glycine Glu, glutamic acid and Asp, aspartic acid. 

Catecholamines, nerve transmitters monitored in brain and heart patients, are separated on C18 using octane sulfonate ion pairing in 6% An/water (pH 3) with added EDTA and phosphate. Detection can be at UV, 270 nm, or by electrochemical detection at +0.72 V for maximum sensitivity. Other tyrosine and tryptophan metabolite neurotransmitters such as serotonin, VMA, and HMA can be analyzed with ion pairing and EC detection. 

Window diagrams and related methods may in principle be applied to optimization problems in more than one dimension. The main difference compared with one-parameter problems is that graphical procedures become much more difficult and that the role of the computer becomes more and more important. Deming et al. [558,559] have applied the window diagram method to the simultaneous optimization of two parameters in RPLC. The volume fraction of methanol and the concentration of ion-pairing reagent (1-octane sulfonic acid) were considered for the optimization of a mixture of 2,6-disubstituted anilines [558]. A five-parameter model equation was used to describe the retention surface for each solute. Data were recorded according to a three-level, two-factor experimental... 

Eicompak AC-GEL 0.07 M-Phosphate buffer containing 60 ppm of Na2 EDTA, 0.065% of tetramethyl ammonium chloride and 0.3 of sodium octane-sulfonate Electrochemical Mouse brain tissues. An immobilized enzyme column with ChO and AChE was used. [172]... 

FIGURE 4-10. Comparison of retention on different phases. Columns 8 mm x 10 cm Radial Pak containing Nova-Pak bonded phases, (a) The mobile phase for the C,8 column is acetonitrile water (17.5 82.5) with 5 mM tetrabutylamine (PIC A) the mobile phase for the phenyl column is acetonitrile water (17.5 82.5) with 5 mM tetrabutylamine (PIC A). Flow rate 4 mL/min. Detection 254 nm. Sample—cephalosporin antibiotics 1. cephradine 2. cefotaxime 3. cefazolin 4. cefuroxime 5. cefoxitin 6. cefoperazone 7. cefamondole 8. cephalothin. (b) The mobile phase for the C)8 column is tetrahydrofuran methanol water (10 27.5 62.5) with 5 mM octane-sulfonic acid (PIC B8) the mobile phase for the CN column is tetrahydrofuran methanol water (5 22 73) with 5 mM octanesulfonic acid (PIC B8). Flow rate 2 mL/ min. Detection 254 nm. Sample—Beta-adrenergic blockers 1. atenolol 2. nadolol 3. pindolol 4. metoprolol 5. timolol. 

OSAS, octane sulfonic acid sodium salt monohydrate. SDS, sodium dodecyl sulfate. 

Ion-pair reagent Concentration (%) 1-Butane sulfonic acid 1-Pentane sulfonic acid 1-Octane sulfonic acid... 

Octane-sulfonic-acid Duodecane-sulfonic-acid Dodecylbenzenesulphonic acid silanized sihcagel MeOH—H20-HAc primary aromatic amines 14)... 

The assay of finished product tablets is accomplished with an HPLC method. The method employs a Octadecyl silane 100 x A.6 mm i.d. column (3 pm particle size) with a mobile phase consisting of 1.08 g octane sulfonic acid, sodium salt in 700 mL of water, 10 mL of glacial acetic acid and 300 mL of acetonitrile. The flow rate is 1.0 mL/minute with UV absorbance detection at 242 nm. 

Table 4.7 HPLC elution gradient program used for analysis of biogenic amines with the method of post-column OPA derivatization. Eluent A) 0.165 M sodium acetate (pH 5.25) and lOmM octane sulfonate eluent B) 0.2 M sodium acetate (pH 4.5) and lOmM octane sulfonate in acetonitrile/H20 (66 34) eluent C) 0.01 M sodium acetate (pH 5.25) and lOmM octane sulfonate flow rate 1 mL/min.

Column uBondapak C18 (300x3.9 mm ID), mobile phase 28% acetonitrile in 0.01 M aqueous octane-sulfonic acid adjusted to pH 3.5, flow rate 1 ml/min, detection UV 230 nm. 

To improve the sensitivity of the pilocarpine analysis - enabling determinations in biological fluids - Mitra et al.7 developed a derivatization technique by means of which pilocarpine was quaternarized with the aid of -nitrobenzylbromide (0.25 mg/ml - 24 hrs at 40°C). The quaternary derivatives were analyzed on an octadecyl column using 0.001 M sodium octane-sulfonate in methanol - water (4 1) as mobile phase, the derivatization technique described was also applicable to other amines. 

HPICE Ion- exclusion -SO, HC1 Octane-sulfonic acid aliphatic carboxylic adds, borate, silicate, carbonate, alcohols, aldehydes... 

MPIC Cations Ion-pair formation neutral HC1 Hexane-sulfonic acid Octane-sulfonic acid In addition to the cations listed under HPIC alkylamines, alkanolamines, quaternary ammonium compounds, cationic surfactants, sulfonium compounds, phosphonium compounds... 

Fig. 8-35. Boric acid determination in a nickel/iron plating bath. — Separator column IonPac ICE-AS1 eluent 0.001 mol/L octane-sulfonic acid flow rate 1 mL/min detection suppressed conductivity injection 50 pL sample (1 1000 diluted).

Figure 13.6 Indirect detection of anions and cations. Stationary phase //-Bondapak-Phenyl. Mobile phase naphthalene-2-sulfonate 4 x 10 M in 0.05 M phosphoric acid. Sample (1) butyl sulfate, (2) pentyl amine, (3) hexane sulfonate, (4) hep-tylamine (5) octane sulfonate (6) octyl sulfate (S) system peak. Reproduced with permission from J. Crommen, G. Schill, D. West-erlund and L. Hackzell, Chromatographia, 24 (1987) 252 (Fig. 1).

Figure 2 demonstrates the effects of adding octane sulfonic acid to the injection solvent for a reverse-phase separation of pyridinium and deoxypyri-dinium, components of collagen, in rat urine. These polyamine containing compounds are protonated and poorly retained under the usual acidic or neutral mobile-phase conditions. The sample preparation method is simple dilution and does not afford the removal of salts from the sample. Therefore if the analytes were inadequately retained the sensitivity, as well as the method accuracy, would suffer. As the concentration of octane sulfonic acid is increased to 50 mM (Fig. 2a), both the retention time and the peak response for the analytes improve significantly. Litde improvement is obtained at higher concentrations of octane sulfonic acid and retention is not strongly dependent on the injection volume (Fig. 2b). To protect the ion source from the fouling effects of octane sulfonic acid in the injection solvent, a timed divert valve was inserted before the ion source to shunt the excess ion pair reagents to waste during the first few minutes of each injection.

Figure 2 Effect of (a) injection solvent concentration of octane sulfonic acid and (b) injection volume containing 50 mM octane sulfonic acid on retention time and electrospray peak area response for pyridinoline and deoxypyridino-line in a reverse-phase LC/MS/MS separation. (From Ref 34.)...

This means that for 1-alcohols, CH3-(CH2) -CH20H, the A parameter (n = 0) is in principle the AG" value of ethanol, and for hydrocarbons the A value is AG" of ethane. Values of the A and B parameters for the varions systems are presented in Table 6.8. Basically all systems fit Equation 6.28 well, and it also turns out that the B parameter is surprisingly constant for nearly all systems. Exceptions are phenylalcohols in sodinm deoxycholate micelles and primary alcohols in lithium perfluoro-octane-sulfonate. The average value of the B parameter for all other systems is -2.48 0.06 kJ/mol... 

The solubilizing power of a tetradecylammonium bromide-sodium octane sulfonate mixture for equal amounts of water and hydrocarbon at 50°C is less than that of the individual components and decreases sharply as the surfactant... 

Tetrabutylammonium phosphate Tetramethylammonium hydrogen sulfate Cetyltrimethylammonium hydrogen sulfate Butane sulfonic acid Pentane sulfonic acid Hexane sulfonic acid Octane sulfonic acid Dodecane sulfonic acid 1-Pentane sulfonate, sodium 1-Octane sulfonate, sodium 1-Dodecyl sulfate, sodium... 

Mobile phase MeCN MeOH buffer 60 30 5, pH adjusted to 3.8 with glacial acetic acid (Buffer was 50 mM ammonium acetate containing 10 mM sodium octane sulfonate.) Flowrate 1.2 Ipjection volume 50 Detector UV 330... 

As a thermally driven process, the photoacid diffusion length and rate in CARs is temperature dependent, as illustrated in Fig. 17.24 for the diffusion of perfluoro-octane sulfonate photoacid in partially protected poly(4-t-butyloxycarbonyloxy-strene)-based resist. Within normal processing conditions, the higher the PEB temperature, the faster is the rate of the photoacid diffusion and the longer is the diffusion length. Although the PEB temperature can be used to modulate photoacid diffusion and consequently resist sensitivity, it nevertheless involves a trade-off... 

HPLC mobile phase 50 mM KH2PO4 containing 3 mM sodium 1-octane-sulfonate, pH 2.5. 

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