Separator Nucleosil

Anion-exchange HPLC (Nucleosil 5SB column) with 50 mmol formic acid-triethylamine in methanol-water (5 95) mobile phase at pH 2.6 and 30 °C cation-exchange separation (Nucleosil 5SA column) with triethylamine in acetonitrile-water-acetic acid (12.5 82.5 5) mobile phase at pH 3.9 and 6 °C on-line ESI-MS analysis of the column effluents... 

Figure 6.3 Conparlson of the separation of the octylphenol poly(ethylene glycol) ether, Triton X-16S on a packed column, left, and an open tubular column, right, using UV detection. For the packed column separation al0cmx2mmI.D. column packed with Nucleosil C g, d. 3 micrometers, temperature > 170 C, and mobile phase carbon dioxide (2 ml/min] and methanol (0.15 nl/rnin). pressure programmed from 130 to 375 bar in 12 min were used. For the open tubular column separation a 10 m x 50 micrometers I.O., SB-Biphenyl-30, temperature = 175°C, mobile phase carbon dioxide (0.175 ml/min) and 2-propanol (0.0265 ml/min) pressure programmed, 125 bar for 5 min, then ramped from 125 to 380 bar over 19.5 min, and held at 380 bar for 15 min. were used. (Reproduced with permission from ref. 57. Copyright Preston Publications, Inc.) ...

Figure 6.8 Separation of Triton X-114 by SFC using prograMmed elution on a 10 cm x 2 mm I.D. Nucleosil column, 3 micrometer packing, at 170 C with UV detection at 278 nm. The separation on the left was performed under isobaric conditions at 210 bar with a mobile phase of carbon dioxide -t- methanol (2 + 0. 5) ml/min. The separation in the center was obtained using a ccmt. sition gradient from 0.025 to 0.4 ml/mln over 8 min with other conditions as above. The separation on the right was obtained using a pressure program from 130 to 375 bar over 8 min with the same mobile phase used for the isobaric sepeuration. (Reproduced with permission from ref. 57. Copyright Preston Publications, Inc.)...

FIGURE 17.8 LCCC separation of FAE with different end groups, stationary phase M N Nucleosil Cig, 25 x 0.46 cm i.d., mobile phase Me0H H20 88 12% by volume, flow rate 1 mL/min (reprinted from Pasch et al., 2005, with permission of European Polymer Federation). 

FIGURE 17.15 LCCC separation of a PEO-PPO-PEO triblock copolymer with regard to the PPO block, stationary phase Nucleosil RP-18, eluent methanol-water 86 14% by volume. 

Procedure Phenolic acids were detected between 210 and 360 nm using a Hewlett Packard diode array detector (HP 1100 HPLC system). The separation was achieved with a Nucleosil 100-5 C18 column 5 pm 4.0x250 mm (Agilent Technologies, USA) at a flow rate of 1.0 ml/min and injection volume of 5 mL. For the elution, a discontinuous acetonitrile-water gradient was used 15% acetonitrile (5 min), 30% acetonitrile (20 min), 40% acetonitrile (25 min), 60% acetonitrile (30 min), 60% acetonitrile (35 min) and... 

Purification of the conjugates may be done by reverse phase HPLC separation. Dry the reaction solution under a nitrogen stream and reconstitute in a minimum volume of acetonitrile/water (1 1, v/v). Apply the sample to a 5 pm Cig-silica HPLC column (250 X 4.6 mm, Nucleosil). Elute with a gradient of water to acetonitrile at a flow rate of 1 ml/minute over a time course of 30 minutes. Free BNAH and BNAH-glycan derivatives can be monitored by absorbance at 275 nm. The conjugate peak also will be positive for carbohydrate by reaction with orcinol, which can be detected by spray after spotting a small eluted sample on a TLC plate. 

Chiral stationary phases (CSP) have been synthesized by ROMP techniques. The separation of dinitrobenzoylphenylalanine can be achieved on a poly(N-(norborn-5-ene-2-carboxyl)-L-phenylalanine ethylester) grafted to Nucleosil 300-5 (43). 

Fig. 11 Separation of phenacyl esters of the isomeric octadecenoic acids, petroselinic acid (6-18 1), oleic acid (9-18 1), and vaccenic acid (11-18 1) by HPLC on silver ion column (Nucleosil 5SA) loaded with silver ion eluted with dichloromethane-dichloroethane-acetonitrile 50 50 0. 25 (vol vol) detection light-scattering detector. (From W.W. Christie, Analusis 26 M38 (1998), reproduced with permission.)...

Cobb and Novotny (7) obtained improved separations using C)8 microcolumns as a method for separating quantities on the order of 4 picomoles of tryptic peptides of phosphorylated and dephosphorylated /3-casein. Figure 4 shows two peaks with different retention times, corresponding to the phosphorylated and dephosphorylated forms of the same peptide. The rest of the peptide map is similar. Using this microcolumn, phosphorylation of a single amino acid on a protein can be detected. The method is reproducible with standard deviations smaller than 2%. Characterization of bovine /3-lg tryptic peptides by RP-HPLC on a Nucleosil Cl 8 column was also reported (123). 

Spherisorb columns from Phase Separations (Queensferry, U.K.) LiChrosorb columns from Merck (Darmstadt, F.R.G.) Nucleosil columns from Macherey-Nagel (Duren, F.R.G.) APEX-MF columns from Jones Chromatography (Llan-bradach, U.K.). 

Christie and Breckenridge (42) describe the application of this column to the isolation and determination of FAs containing trans double bonds in samples of natural and industrial origin. A column (250 X 4.6-mm ID) of NUCLEOSIL 5SA was flushed with 1% ammonium nitrate solution at a flow rate of 0.5 ml/min for 1 h, then with distilled water at 1 ml/min for 1 h. Silver nitrate (0.2 g) in water (1 ml) was injected onto column via the Rheodyne valve in 50-yu.l aliquots at 1-min intervals silver began to elute from the column after about 10 min, and 20 min after the last injection the column was washed with methanol for 1 h, then with 1,2-dichloroethane-dichloromethane (1 1 v/v) for 1 h. For most of the analytical work, the column temperature was maintained at 30°C in a thermostatted oven. 1,2-Dichloroethane-dichloromethane (1 1) (mixture A) at a flow rate of 1.5 ml/min was the mobile phase (detector operated at 242 nm) for the separation of isomeric monoenes, and the same solvents with the addition of 0.5% acetonitrile (mixture B) at a flow rate of 0.75 ml/min were employed for isomeric dienes and trienes. 

Bernhard et al., on the other hand, selected 5-fim spherical Nucleosil-NH2 as the stationary phase (43). In order to improve the resolution of the early-eluting components and to reduce the overall time needed per analysis, they set up an isocratic HPLC system, including two separate columns. By means of a switch valve, the second 175-mm column could be excluded after the elution of PC, SPH, LPC, /V-methyl PE, PG, and PE. This enabled the rapid elution of the acidic phospholipids PI and PS from the 50-mm column and hence significantly decreased the total run time (Fig. 3). The mobile phase contained 1460 ml A, 500 ml M, 30 ml W, and 600 jj, 1... 

Fig. 3 Separation of standard and liver phospholipids by HPLC on a 5-yttm Nucleosil 5 NH2 stationary phase with an isocratic mobile phase consisting of acetonitrile, methanol, water, and methyl phosphonic acid and subsequent UV and fluorescence detection. The second column was cut off from the eluent stream by valve switching after about 30 min. (Reprinted from Ref. 43 with the kind permission of Analytical Biochemistry.)...

Fig. 5 HPLC profile of the Spectralipid SN standard mixture monitored by ELSD after HPLC separation of the phospholipid components on a Nucleosil 100-7 Diol stationary phase. The mobile phase included hexane, 2-propanol, butanol, tetrahydrofuran, iso-octane, and water in a binary gradient. (Reprinted from Ref. 69 with the kind permission of the authors and of Elsevier Science Publishers.)...

Data calculated from the peak areas of diphenylhexatriene fluorescence (340/460 nm) and UV absorption (205 nm) following HPLC separation of the phospholipids on a 5-/x,m Nucleosil 5 NH2 stationary phase. Egg PC was set as 1. 

Another approach would be to derivatize cyclamate prior to analysis. Cyclamate can be determined by HPLC and UV detection at 314 nm after conversion to A/,/V-dichlorocyclohexyl-amine. Derivatization can be carried out directly in the sample or after extraction and cleanup. /V,/V-Dichlorocyclohexylamine is separated on a reverse-phase column (Nucleosil Cl8 or Fine-pak SIL Cl8 T-5) with a mobile phase of methanol water, 8 2 v/v (43,46). Cyclamate can also be determined at 585 nm after postcolumn derivatization with methyl violet 2B as described by Lawrence and Charbonneau (16). 

Berge and Deye studied the effect of column surface area on the retention of polar solutes [18]. They found that there was a linear relationship between retention and the surface area. 4-Hydroxy benzoic acid was used as a model acidic compound, and sulfamethazine, sulfanilamide, sulfi-somidine, and sulfapyridine were used as the model basic compounds. The separations were carried out on a packed Nucleosil Diol column with a methanol-modified carbon dioxide as the mobile phase. The UV detector was used for the analysis. It was observed that 0.1% acetic acid for the acidic solutes and 0.1% isopropylamine for basic solutes was required in the methanol to achieve the separations. The efficiency was found to be similar for 100-, 300-, and 500-A packing materials. 

Marko Varga et al. [45] found that a cleanup column prior to the separation column, packed with a chemically bonded amine material (Nucleosil 5 HN2) was found to be effective in removing interfering humic substances. No influence was found from humic substances in concentrations up to 45 pg L 1 on ion chromatographic analysis of nitrate and sulphate (10-100mg L ) after passage through the cleanup column. 

The residue is taken up in 200pL of methanol and 20pL of the latter are injected into the chromatograph. Separation is achieved by elution through a 250 x4mm id column packed with Nucleosil reversed phase Ci8 (particle size 5pm). 

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