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Silica mobilization

Chlorinated pesticides Aldrin, endrin Separated on a C-18, C-8 or CN- high-temperature bonded silica mobile phase isooctane—ethyl acetate (97 3) and detected by UV at 254 nm... [Pg.95]

Figure 7.15 Separations of opium alkaloids on bare silica. Column = x 0.46 cm ID stationary phase, 5-/im LiChrosorb Si-60 silica mobile phase, carbon dioxide-methanol-methylamine-water (83.37 16.2 0.15 0.23, w/w) Solutes 1, narcotine 2, papaverine 3, thebaine 4, codeine 5, crytopine 6, morphine. [Reprinted from Ref.20, J. Chromatogr. 437, 351 (1988) with kind permission of Elsevier Science Publishers, The Nether-, lands.]... Figure 7.15 Separations of opium alkaloids on bare silica. Column = x 0.46 cm ID stationary phase, 5-/im LiChrosorb Si-60 silica mobile phase, carbon dioxide-methanol-methylamine-water (83.37 16.2 0.15 0.23, w/w) Solutes 1, narcotine 2, papaverine 3, thebaine 4, codeine 5, crytopine 6, morphine. [Reprinted from Ref.20, J. Chromatogr. 437, 351 (1988) with kind permission of Elsevier Science Publishers, The Nether-, lands.]...
Changes in mobile-phase components such as pH, ionic strength, and water content have been systematically studied [3,310,316,317]. These studies indicate that retention of basic analytes is mediated primarily by the cation-exchange properties of the silica [2]. Interestingly, it has been suggested from retention data of various pharmaceuticals that the retention mechanisms of silica with aqueous eluents and reversed-phase systems are similar [317,318]. Due to the ion-exchange properties of silica, mobile-phase pH adjustments are useful in changing the retention of ionic compounds. [Pg.348]

Figure 1. Liquid chromatographic sefxiration of an ethyl acetate liver extract of barbiturates. Column reverse phase, n-octadectjl groups chemically bonded to 10 p. silica mobile phase methanol/water. Figure 1. Liquid chromatographic sefxiration of an ethyl acetate liver extract of barbiturates. Column reverse phase, n-octadectjl groups chemically bonded to 10 p. silica mobile phase methanol/water.
Fig. 10.24. Separation of benzodiazepines by CEC. Column, 200 mm (effective length) x 100 pm i.d. packed with cholesteryl-bonded silica. Mobile phases (A), acetonitrile-5 mM Tris-HCl buffer pH 7.7 (35 75 v/v) (B), acetonitrile-5 mM Tris-HCl buffer pH 73 (35 65 v/v). Applied voltage 300 V/cm. Reproduced with permission from Jinno et al. [176],... Fig. 10.24. Separation of benzodiazepines by CEC. Column, 200 mm (effective length) x 100 pm i.d. packed with cholesteryl-bonded silica. Mobile phases (A), acetonitrile-5 mM Tris-HCl buffer pH 7.7 (35 75 v/v) (B), acetonitrile-5 mM Tris-HCl buffer pH 73 (35 65 v/v). Applied voltage 300 V/cm. Reproduced with permission from Jinno et al. [176],...
Yardley B. W. D. and Bottrell S. H. (1992) Silica mobility and fluid movement during metamorphism of the Connemara schists, Ireland. J. Metamorph. Geol. 10, 453—464. [Pg.1491]

Fig. 1 SFC separation of synthetic mixture of polymethoxy-lated flavones. Column, 250 mm x 4.6 mm I.D. stationary phase, Zorbax (5 pm) silica mobile phase, carbon dioxide modified with 10% methanol inlet pressure, 220 atm outlet pressure, 200 atm column temperature, 40°C carbon dioxide flow-rate, 3 mL/min methanol flow-rate, 0.3 mL/min UV detection at 313 nm. Peaks 1 =tangeretin 2=heptamethoxy-flavone 3 = nobiletin 4 = sinensetin 5 = tetramethylisoscutellar-ein 6=isosinensetin. Fig. 1 SFC separation of synthetic mixture of polymethoxy-lated flavones. Column, 250 mm x 4.6 mm I.D. stationary phase, Zorbax (5 pm) silica mobile phase, carbon dioxide modified with 10% methanol inlet pressure, 220 atm outlet pressure, 200 atm column temperature, 40°C carbon dioxide flow-rate, 3 mL/min methanol flow-rate, 0.3 mL/min UV detection at 313 nm. Peaks 1 =tangeretin 2=heptamethoxy-flavone 3 = nobiletin 4 = sinensetin 5 = tetramethylisoscutellar-ein 6=isosinensetin.
Figure 10.16 Comparison of calculated (solid line) and experimental (symbols) band profiles. General conditions L = 25 cm dc = 4.6 mm Fi, = 1 mL/min (a,c,d) or 2 mL/min (b) N = 5000 plates, (a) Benzyl alcohol on silica. Mobile phase solution of THF in n-hexane (15 85). Sample sizes (mmol) 1, 0.0025 2, 0.00625 3, 0.0125 4,0.025 5, 0.060 6, 0.075. (b) Acetophenone on silica. Mobile phase mixture of ethyl acetate and -hexane (2.5 97.5). Sample sizes (mmol) 1, 0.025 2 0.05 3 0.075 4 0.1 5 0.125. (c) Benzyl alcohol on oc-tadecyl silica. Mobile phase, methanol/water (20 80) sample sizes (mmol) 1, 0.02 2,0.05 3, 0.10 4, 0.15. (d) Phenol on octadecyl chemically bonded silica. MobUe phase mixture of methanol and water (20 80). Sample sizes 1, 0.015 mmol 2 0.03 mmol 3 0.045 mmol 4 0.06 mmole 5 0.075 mmol. Reproduced with permission from S. Golshan-Shirazi and G. Guiochon, Anal. Chem., 60 (1988) 2634 (Figs. 7 to 10). 1988, American Chemical Society. Figure 10.16 Comparison of calculated (solid line) and experimental (symbols) band profiles. General conditions L = 25 cm dc = 4.6 mm Fi, = 1 mL/min (a,c,d) or 2 mL/min (b) N = 5000 plates, (a) Benzyl alcohol on silica. Mobile phase solution of THF in n-hexane (15 85). Sample sizes (mmol) 1, 0.0025 2, 0.00625 3, 0.0125 4,0.025 5, 0.060 6, 0.075. (b) Acetophenone on silica. Mobile phase mixture of ethyl acetate and -hexane (2.5 97.5). Sample sizes (mmol) 1, 0.025 2 0.05 3 0.075 4 0.1 5 0.125. (c) Benzyl alcohol on oc-tadecyl silica. Mobile phase, methanol/water (20 80) sample sizes (mmol) 1, 0.02 2,0.05 3, 0.10 4, 0.15. (d) Phenol on octadecyl chemically bonded silica. MobUe phase mixture of methanol and water (20 80). Sample sizes 1, 0.015 mmol 2 0.03 mmol 3 0.045 mmol 4 0.06 mmole 5 0.075 mmol. Reproduced with permission from S. Golshan-Shirazi and G. Guiochon, Anal. Chem., 60 (1988) 2634 (Figs. 7 to 10). 1988, American Chemical Society.
Figure 11.21 Comparison of experimental (symbols) and calculated (solid lines) individual elution profiles. 2-phenylethanol and 3-phenylpropanol. Calculations made with the forward-backward scheme, the coefficients of the competitive isotherm Langmuir model derived from the single-component isotherms, and a rectangular injection profile. Column 25 cm long, packed with 10 mm Vydac ODS silica. Mobile phase methanol-water, (50 50), 1 mL/min. (a) Sample size 7.6 mg of 2-phenylethanol and 21.1 mg of 3-phenyl-l-propanol. (b) Sample size 30.1 mg of 2-phenylethanol and 10.2 mg of 3-phenyl-l-propanol. Inset Band profiles calculated for a sample twice as large, using a competitive Langmuir isotherm model. Reproduced with permission from AM. Katti and G. Guiochon, J. Chromatogr., 499 (1990) 21 (Figs. 4, 6 and 7). Figure 11.21 Comparison of experimental (symbols) and calculated (solid lines) individual elution profiles. 2-phenylethanol and 3-phenylpropanol. Calculations made with the forward-backward scheme, the coefficients of the competitive isotherm Langmuir model derived from the single-component isotherms, and a rectangular injection profile. Column 25 cm long, packed with 10 mm Vydac ODS silica. Mobile phase methanol-water, (50 50), 1 mL/min. (a) Sample size 7.6 mg of 2-phenylethanol and 21.1 mg of 3-phenyl-l-propanol. (b) Sample size 30.1 mg of 2-phenylethanol and 10.2 mg of 3-phenyl-l-propanol. Inset Band profiles calculated for a sample twice as large, using a competitive Langmuir isotherm model. Reproduced with permission from AM. Katti and G. Guiochon, J. Chromatogr., 499 (1990) 21 (Figs. 4, 6 and 7).
Figure 14.10 Comparison of experimental results and the prediction of a best fit kinetic model. Column, 2.1 x 50 mm packed with immobilized Concanavalin A on silica mobile phase, 0.02 M sodium phosphate buffer at pH 6.0, with 0.5 M NaCl, 0.01 M MgCl2 and 0.001 M CaCl2 T = 25 2°C Fv = 1 mL/min fg = 9.53 s. Sample size, 719 mol. Model parameters 7 = 8.203 k =... Figure 14.10 Comparison of experimental results and the prediction of a best fit kinetic model. Column, 2.1 x 50 mm packed with immobilized Concanavalin A on silica mobile phase, 0.02 M sodium phosphate buffer at pH 6.0, with 0.5 M NaCl, 0.01 M MgCl2 and 0.001 M CaCl2 T = 25 2°C Fv = 1 mL/min fg = 9.53 s. Sample size, 719 mol. Model parameters 7 = 8.203 k =...
Figure 18.40 Example of purification by preparative chromatography. Purification of the enantiomers of a benzodiazepinone on 4.6 x 250 mm column of ceUulose tribenzoate coated on 10 Jim silica. Mobile phase, n-hexane-2-propanol (40 60), 0.25 mL/min, at 49oC. (a) Preparative chromatogram, 0.75 mg. (b) Analysis of fractions B (dashed line) and D (soUd line). Reproduced with permission from A. Katti, P. Erlandsson and R. Ddppen, J. Chromatogr., 590 (1992) 127(Figs. 3 and 5). Figure 18.40 Example of purification by preparative chromatography. Purification of the enantiomers of a benzodiazepinone on 4.6 x 250 mm column of ceUulose tribenzoate coated on 10 Jim silica. Mobile phase, n-hexane-2-propanol (40 60), 0.25 mL/min, at 49oC. (a) Preparative chromatogram, 0.75 mg. (b) Analysis of fractions B (dashed line) and D (soUd line). Reproduced with permission from A. Katti, P. Erlandsson and R. Ddppen, J. Chromatogr., 590 (1992) 127(Figs. 3 and 5).
Figure 18.8 Individual stages in the determination of tobramycin. Conditions column 1, 3cm X 4.6mm i.d. with 10(xm cation exchanger column 2, 12.5cm x 4.6mm i.d. with 5ixm RP-18 scavenger column, 2.5cm x 2.2cm i.d. with 37-54iim silica mobile phase 1,1.5 ml min of 10 mM sodium phosphate buffer (pH 5.2) mobile phase 2, 1.5 ml min of 50 mM EDTA (pH 8.8). Figure 18.8 Individual stages in the determination of tobramycin. Conditions column 1, 3cm X 4.6mm i.d. with 10(xm cation exchanger column 2, 12.5cm x 4.6mm i.d. with 5ixm RP-18 scavenger column, 2.5cm x 2.2cm i.d. with 37-54iim silica mobile phase 1,1.5 ml min of 10 mM sodium phosphate buffer (pH 5.2) mobile phase 2, 1.5 ml min of 50 mM EDTA (pH 8.8).
Figure 19.10 Peak areas and system peaks. (Reproduced by permission of Elsevier Science Publishers BV from G. Sehili and J. Crommen, Trends Anal. Chem., 6, 111 (1987).) The two peaks indicated by Sare system peaks. Sample, racemate of bupivacaine (equal amounts of both isomers) stationary phase, EnantioPac (aq-acid glycoprotein on silica) mobile phase, phosphate buffer (pH 7.2)-isopropanol (92 8), UV detector, 215 nm (the mobile phase shows some absorbance at this wavelength). Figure 19.10 Peak areas and system peaks. (Reproduced by permission of Elsevier Science Publishers BV from G. Sehili and J. Crommen, Trends Anal. Chem., 6, 111 (1987).) The two peaks indicated by Sare system peaks. Sample, racemate of bupivacaine (equal amounts of both isomers) stationary phase, EnantioPac (aq-acid glycoprotein on silica) mobile phase, phosphate buffer (pH 7.2)-isopropanol (92 8), UV detector, 215 nm (the mobile phase shows some absorbance at this wavelength).
Figure22.5 Reaction of (/ ,S)-metoprolol with (S)-fezr-butyl 3-(chloroformoxy)-butyrate and determination of the ratio of enantiomers in human plasma (reproduced with permission from A. Green, S. Chen, U. Skantze, I. Grundevik and M. Ahnoff, poster at the 13th International Symposium on Column Liquid Chromatography, Stockholm, 1989.) Conditions stationary phase, octadecyl silica mobile phase, phosphate buffer-acetonitrile (1 1) fluorescence detector 272/312 nm. Figure22.5 Reaction of (/ ,S)-metoprolol with (S)-fezr-butyl 3-(chloroformoxy)-butyrate and determination of the ratio of enantiomers in human plasma (reproduced with permission from A. Green, S. Chen, U. Skantze, I. Grundevik and M. Ahnoff, poster at the 13th International Symposium on Column Liquid Chromatography, Stockholm, 1989.) Conditions stationary phase, octadecyl silica mobile phase, phosphate buffer-acetonitrile (1 1) fluorescence detector 272/312 nm.
Liquid silica, Mobilities, related to diffusion coefficients,... [Pg.49]

Column 250 X 4.6 5 )i.m Phenomenex < ano-bonded silica Mobile phase MeCN water phosphoric acid 400 600 1 Flowrate 1.5 Detector UV 225... [Pg.834]

Guard column 5 pm Guard-Pak Resolve Si (dead volume 60-75 pL) Column 75 x 3.9 4 pm Nova-Pak silica Mobile phase Dichloromethane EtOH 34 1... [Pg.878]

Even if the sandstones of the basins investigated are nearly always intercalated with silty-argillaceous rocks of a thickness well above that of the sandstones themselves, the water supplied during their dehydration will not suffice to transport such a vast amount of silica mobilized by pressure solution or derived from another source. Under this situation the polycyclical circulation of fluids by convection could be a highly probable mechanism explaining the transport of silica (Fig. 4.15), in particular by the... [Pg.171]

Figure 2. High performance liquid chromatogram of a preparation of 2-deoxy-2-fluoro-D-glucose. Stationary phase, aminopropyl banded silica mobile phase, 70% aqueous acetonitrile at l.SmL/min. The large peak in the upper panel is 2FDG. Figure 2. High performance liquid chromatogram of a preparation of 2-deoxy-2-fluoro-D-glucose. Stationary phase, aminopropyl banded silica mobile phase, 70% aqueous acetonitrile at l.SmL/min. The large peak in the upper panel is 2FDG.
Figure 6. High performance liquid chromatogram if F-18 in rat heart rate after Injection of 3-deoxy-3-fluoro-D-glucose. Stationary phase, anion-exchange bonded silica mobile phase, 20nM potassium phosphate, PH 4.5 Peak assignments in order of elution 3FDG, unknown, unknown, 3FDG-6-phosphate. (Reproduced with permission from Ref. 49. Copyright 1984 American Physiological Society.)... Figure 6. High performance liquid chromatogram if F-18 in rat heart rate after Injection of 3-deoxy-3-fluoro-D-glucose. Stationary phase, anion-exchange bonded silica mobile phase, 20nM potassium phosphate, PH 4.5 Peak assignments in order of elution 3FDG, unknown, unknown, 3FDG-6-phosphate. (Reproduced with permission from Ref. 49. Copyright 1984 American Physiological Society.)...
Figure3.68 Injection of 50g of product on a cyano-modified silica. Column 110mm I.D. DAC filled with 2000g of 10pm Kromasil 60 A-cyano-modified silica, mobile phase n-heptane,... Figure3.68 Injection of 50g of product on a cyano-modified silica. Column 110mm I.D. DAC filled with 2000g of 10pm Kromasil 60 A-cyano-modified silica, mobile phase n-heptane,...
Figure3.69 Injection ofSOgon acolumn filled with 2000gof 10(tm Kromasil 60A-cyano-with silica connected with a column filled with a modified silica, mobile phase n-heptane, flow cyano-modified silica. Pre-Column 110 mm I.D. rate 750 ml min temperature eluent 28°C, DAC filled with 500g of lOjtm Kromasil 60 A- column 30°C, sample amount 50g dissolved Silica gel. Main Column 110 mm I.D. DAC filled in 292 ml ofn-heptane. Figure3.69 Injection ofSOgon acolumn filled with 2000gof 10(tm Kromasil 60A-cyano-with silica connected with a column filled with a modified silica, mobile phase n-heptane, flow cyano-modified silica. Pre-Column 110 mm I.D. rate 750 ml min temperature eluent 28°C, DAC filled with 500g of lOjtm Kromasil 60 A- column 30°C, sample amount 50g dissolved Silica gel. Main Column 110 mm I.D. DAC filled in 292 ml ofn-heptane.
Photograph 7-35 Clear belite ring around central pore formed by silica mobilization during sintering of coarse quartz in feed. (S A6655)... [Pg.91]

Hgure 2 Separation of the enantiomers of oxazepam acetate and oxazepam on a chiral stationary phase. Column 4.6 mm X 25 cm stationary phase (S)-dinitrobenzoylleucine covalently bonded to 5 pm silica mobile phase, hexane-ethanol-acetonitrile (91.5 5.7 2.8, v/v/v), 2mlmin detector, UV 231 nm. Racemic oxazepam 3-acetate was hydrolyzed by human liver microsomes, giving racemic oxazepam. The micro-somes strongly preferred the (R) enantiomer after incomplete hydrolysis the remaining oxazepam acetate had a composition of 91.8% (S) and 8.2% (R) enantiomers. (Reproduced from Yang SK, Liu K, and Guengerich FP (1990) Enantioseleclive hydrolysis of oxazepam 3-acetate by esterases in human and rat liver microsomes and rat brain S9 fraction. Chirality 2 150.)... [Pg.2608]

Column 250 x 2.2 6-8 [xm silica Mobile phase n-Hexane EtOH 98.5 1.5 Flow rate 0.55 Injection volume 5 Detector Transport flame ionization... [Pg.622]

To illustrate the principles discussed above, two case examples are examined to determine the controlling mechanisms of silicate dissolution, and the final outcome. In the first case study, organic acids preferentially mobilize silica in a microbially active oil-contaminated aquifer, whereas the second study shows a transition between enhanced aluminum mobility at acidic pH and enhanced silica mobility at neutral pH in a peat bog. [Pg.189]

FIGURE 15 Analytical (a) and preparative (b) isolation of vitamin B-12 intermediates, (a) Column, 180 x 0.2-cm i.d., Corasil II, 37-50 />tm mobile phase, hexane/isopropanol/methanol. (b) Column, 240 x 2.3 cm i.d. 37-80 ju,m silica mobile phase, hexane/isopropanol/methanol (5 2 1), flow rate 34 ml/min injected sample, 5 g. [From Snyder, L. R., and Kirkland, J. J. (1979). Introduction to Modern Liquid Chromatography, 2nd ed. Wiley, New York, p. 655. Reprinted with permission.]... [Pg.219]

See other pages where Silica mobilization is mentioned: [Pg.712]    [Pg.422]    [Pg.3635]    [Pg.3636]    [Pg.126]    [Pg.520]    [Pg.170]    [Pg.236]    [Pg.185]   
See also in sourсe #XX -- [ Pg.51 ]



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