Heptanesulfonate

Alkyl- and arylsulfonates, e.g., aethane- or heptanesulfonate, caaphorsulfonic acid... 

Fig. 2.98. Separation at 520 nm of red wine (Cabernet Sauvignon) extract before (a), and after (b) addition of 20 mm heptanesulphonic acid to the mobile phase. In (a), the two broad peaks at approximately 40 and 55 min are anthocyanins before heptanesulfonic acid addition and in (b), the two peaks at approximately 12 and 15 min are the same anthocyanins after heptanesulphonic acid addition. Reprinted with permission from J. A. Kennedy et al. [233].

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. 

Figure 4.15 Ion-pair liquid chromatography of free amino acids using a column switching system. Column I, butyl-bonded silica gel, 50 x 4.6 mm i.d., 2, octyl-bonded silica gel, 50 x 4.6 mm i.d., and 3, octadecyl-bonded silica gel, 250 x 4.6 mm i.d. eluent, 0.01 m sodium acetate buffer (pH 5.6) containing 4 mM copper acetate and 0.8 mM sodium heptanesulfonate flow rate, 1 ml min-1 detection, UV 235 nm. Peaks 1, Tyr 2, Val 3, Met 4, His 5, Lys 6, lie, 7, Leu 8, Phe 9, Arg 10, Asp 11, Ser 12, Glu 13, Thr 14, Gly 15, Pro 16, Cys and 17, Ala. 1-9 were separated on column 1 and 10-17 were separated by a combination of columns 2 and 3.

Pyrocarbine, Phyzostygmin Pentanesulfonate Cl8 silica 5 mM Heptanesulfonate, pH 3.6 in 4% MeOH 29... 

Rebamisol Heptanesulfonate Cl8 silica 2% Heptanesulfonate in 0.2% acetic acid + MeOH 30... 

Salbutamol Heptanesulfonate C8 silica 5 mM Heptanesulfonate in 5.8 mM phosphate buffer 31... 

When analyzing very low conductivity samples, it is necessary to add some ions with slow mobility to allow the tension applied to generate current in the sample vial. Eor example, we may add heptanesulfonate (CAS 22767-50-6 at a level of 1.2 mM in the sample) in the sample to thus generate current and EOF. 

The highest theoretical plate number was obtained with 400 ig/mL chloride and 400 j,g/mL of heptanesulfonate. However, when looking at the peak area, we obtained an RSD value of 11.74%, which indicated that stacking and de-stacking only had a minimal effect. Further development was performed without searching for tITP stacking (Figure 22). 

DihydroxyphenyIalanine derivatives Heptanesulfonate H.O-MeOH-HOAc Octadecyl 230... 

Analysis of vitamin content of food materials appears to be a developing field. B vitamins in rice were analyzed using a mobile phase which contained pentanesulfonic acid and heptanesulfonic acid (558). Although the peaks were not sharp, the separation of the vitamins was satisfactory. Vitamin D in fortified milk has b n analyzed after removal Of cholesterol and carotenes in a preliminary cleanup (559, 540). Vitamin A has been analyzed in margarine, infant formula, and fortified milk (541, 542). Reports of the analysis of other vitamins in food are few to te but this mode of analysis can be expected to rapidly expand in the future in light of the variety of vitamin determinations in formulations which have been done (see Section VIII,F,l). 

Hupka et al. [29] developed a method for the determination of morphine and its phase II metabolites, morphine-3-beta-D-glucuronide and morphine-6-beta-D-glucuronide in the blood of heroin victims. The method is based on immunoaffinity SPE, RP-HPLC isocratic separation (mobile phase 90% lOmmol KH2PO4, 2mmol 1-heptanesulfonic acid, adjusted to pH 2.5 with H3PO4 and 10% acetonitrile flow rate 1.5 mL/min), and laser-induced native fluorescence detection. 

TCA extn, liq-liq partn, SPE cleanup, liq-liq partn, 1-heptanesulfonic acid addn... 

Solvent A MeOH/HzO/ HOAc (70 29 1) contg 0.5% heptanesulfonic acid... 

In liquid chromatographic methods, reversed-phase columns are usually employed due to hydrophobic interaction of the amphenicols molecules witli the Cs or Ci8 stationary phases. Ion-pairing liquid chromatography has been also described for the separation of florfenicol and florfenicol amine (62) or chloramphenicol and deacetylchloramphenicol residues (46) using heptanesulfonate or octylsulfate-pairing ions, respectively. 

Tire preferred type of reversed-phase sorbents is Cjg bonded silica (Table 29.4). Using this reversed-phase sorbent, ion-pair separation of lincomycin (154), spiramycin (138), and tylosin (145) residues has also been reported through use of octanesulfonate, heptanesulfonate, and tetrabutylammonium pairing ions, respectively. Phenyl-bonded silica or polymeric stationary phases have also been described for the separation of tilmicosin (133) and lincomycin (146) residues, respectively. 

Liquid chromatographic separation of sedatives and -blockers is usually performed using reversed-phase columns. The preferred type of reversed-phase material is Cig-bonded silica (Table 29.16), but phenyl-bonded silica has also been employed for separation of xylazine and its major metabolite (525). Ion-pair liquid chromatography has also been suggested for separation of carazolol and xylazine residues, by addition to the mobile phase of dodecyl sulfate (522) or heptanesulfonate (520) pairing ions, respectively. 

Ion-pair chromatography has also been used for the separation of aspartame from synthesis intermediates and degradation products. Lawrence and Iyengar (22) and Stamp and Labuza (23) used sodium heptanesulfonate to improve separation of aspartame from its decomposition products. Verzella et al. (21) used sodium hexanesulfonate and gradient elution to separate aspartame from two decomposition products and seven related synthesis by-products (Table 2). This method has been used routinely for the control of aspartame synthesis and as a check of purity of both finished bulk and mother liquor. 

CF, water-soluble vitamins and sodium benzoate HPLC-UV at 210 nm. Column Nucleosil Cl 8, T = 40°C. Mobile phase HzO, ACN, triethylamine, heptanesulfonate (pH = 2.8). 

Sodium 1-heptanesulfonate and acetic acid extraction, filtration. Elution through a Cl 8 SepPak cartridge, conditioned with MeOH, sodium 1-heptanesulfonate. Elution with watcr-ACN mixture to remove interferents and glycoalkaloids elution with ACN and diammonium phosphate buffer. 

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