Eluant water

SEC calibration using polyethylene oxide (PEO) and polysaccharide (PSAC) standards, eolumn PL aquagel-OH 50 300 x 7.5 mm, eluant water, flow rate 1 ml/minute, detector RI. 

Stationary phase dibenzo-18water flow rate 1 mL/min detection direct conductivity solute concentrations 0.7 mg/L Na2S04, 0.1 mg/L NaCi 1 mg/L Nal, 4 mg/L NaSCN, and 8 mg/L NaHC03 (taken from [50]). 

Fig. 4-34. Separation of alkali metals on silica modified with poly(benzo-15-crown-5). - Eluant water flow rate ...

Figure 17. Sugar profile of domestic beer. Several oligosaccharides, along with monosaccharides and ethanol, are resolved in this domestic beer sample using a lead bonded polymeric colunin. Column, CHO-682 (Interaction Chemicals) eluant, water flow-rate, 0.4 ml/min temperature, SO C detection, refractive index (RI).

The solvents used for liquid chromatography are the commoner ones such as water, acetonitrile, and methanol. For the reasons just stated, it is not possible to put them straight into the ion source without problems arising. On the other hand, the very viscous solvents that qualify as matrix material are of no use in liquid chromatography. Before the low-boiling-point eluant from the LC column is introduced into the ion source, it must be admixed with a high-boiling-point matrix... 

Borate-gluconate eluant. Prepare a buffer concentrate by dissolving the following substances in water and making up to 1 L with distilled, de-ionised... 

Column. A Waters IC-PAK A or equivalent anion exchange column, operating at ambient temperature. Equilibrate the column with the mobile phase (eluant) by allowing the latter to flow through the column for 1 hour. 

A mixture of 40 mmol or the a-nitro alcohol 1, 48 mmol of (terf-butyldimethyl)chlorosilane or chlorotri-mcthylsilanc, 6.8 g (100 mmol) of I /(-imidazole and 10 mL of DMF is stirred at 20 C for 12 h. Water is added and the mixtnre is extracted with hexane. The combined extract is washed wilh water and sat. aq NaCl and dried over MgS04. Exaporation gives the O-silyl nitro alcohol as an oil which is distilled (bulb-to-bulb) yield 45 - 97%. If unreacled starting material is present in the distillate, it can be removed by chromatography over silica gel (30 g/ l g of product) with l,t,0/pcntanc 1 9 as eluant. 

A solution of 1-trimethylsilyloxycyclohex-l-ene (5.12 mmol) and benzaldehyde dimethyl acetal (5.47 mmol) in dichloromethane (15 ml) was cooled to —78°C, and to this was added TMSOTf (0.05 mmol) in dichloromethane (0.5 ml). The mixture was stirred at -78°C for 8h, and then quenched by the addition of water at —78 °C. Dichloromethane (50 ml) was added, and the mixture was washed with saturated sodium hydrogen carbonate solution and brine, and dried. Concentration provided a crude oil consisting of a 93 7 mixture of erythro- and r/jreo-2-(methoxyphenyl-methyl)cyclohexanone. Chromatography on silica gel (20g, eluant petroleum ether ether 10 1) gave the pure erythro (82%) and threo (6.7%) isomers as oils. 

Hie hydrolytic depolymerization of nylon-6 was followed by gel permeation chromatography (GPC), viscometry, and gravimetry. GPC determinations were performed on a Waters 150C chromatography system using benzyl alcohol as die eluant, two Plgel 10-p.m crosslinked polystyrene columns, and a differential refractometer detector. The flow rate was 1 mL/min. The concentration of the polymer solutions was 0.5 wt% and dissolution was accomplished at 130°C. 

Transfer the sample to the column. Rinse the sample flask sequentially with 5 mL, 5 mL, and then 10 mL of hexane-ethyl acetate (4 1, v/v). Allow each rinse to drain to the top of the sodium sulfate layer before adding the next portion. Discard the accumulated eluant, place a 100-mL round-bottom flask under the column, and elute the pyriproxyfen residues with 55 mL of hexane-ethyl acetate (4 1, v/v). Evaporate the eluate by rotary evaporation under reduced pressure in a <40 °C water-bath and reconstitute the sample in 2.0 mL of toluene with sonication for analysis (Section 6.2). 

The chemical constituents of the backwash water (which may be acidified) and of the various eluants (recycling, new and special) are specific to the problem of displacing the captured ions from the resin and reactivating its sites. The final stage of IX, namely, the recovery in a solid form of the values from the eluting solution, is effected by chemical methods which yield the desired precipitate. This is settled out, filtered and dried for despatch. 

Figure 9 A synthetic mixture of water-soluble carboxylic acids separated by anion-exchange chromatography. Column 0.3 cm x 300 cm Diaoion CA 08, 16-20 p (Mitsubishi Kasei Kogyo). Eluant 200 mM HC1. Detection reaction with Fe3-benzohy-droxamic acid-dicyclohexy carbodiimide-hydroxylamine perchlorate-triethyl amine with absorbance at 536 nm. Analytes (1) aspartate, (2) gluconate, (3) glucuronate, (4) pyroglutamate, (5) lactate, (6) acetate, (7) tartrate, (8) malate, (9) citrate, (10) succinate, (11) isocitrate, (12) w-butyrate, (13) a-ketoglutarate. (Reprinted with permission from Kasai, Y., Tanimura, T., and Tamura, Z., Anal. Chem., 49, 655, 1977. 1977 Analytical Chemistry).

Gel permeation chromatography was performed in tetrahydrofuran using a Waters pump system and a Model 410 differential refractive index detector for the eluant. Five Ultrastyragel columns with nominal porosities ranging from 500 to 105 angstroms were used for all the samples and the polystyrene standards. 

Carbethoxy-4-piperidone (7.52 g, 43.9 mmol) (Note 6) and p-toluenesulfonic acid (5.0 g, 26 mmol) are added to a 250-mL, round-bottomed flask that contains the above distillate and a magnetic stir bar. The mixture is stirred under vacuum (20 mm) at 100°C for 90 min and the evolved water vapor is collected in a vacuum trap. The mixture is cooled to 23°C and subjected to flash chromatography on silica gel (250 g, 20 cm x 10 cm) using ethyl acetate hexane (1 4) as the eluant (Note 7) to give 9.0 g (59% overall) of (2R.3S)- and (2S,3S)-1,4-dioxa-2,3-dimethyl-2-(1-methylethenyl)-8-... 

C-labelled cholesterol was used to test the recovery of 5-100 pg of faecal sterols from seawater (labelled coprostanol not being available). The radioactivity of the samples and eluates was measured by a two-channel liquid scintillation counter. Percentage recovery was calculated on the basis of the amount of labeled material recovered in the acetone eluant. The results indicate that column extraction efficiency is not adversely affected by the salinity of the water samples, i.e., in the range 95-97%. 

Gel permeation chromatography (GPC) was carried out on a Waters 720 GPC instrument using a methylene chloride eluant and a series of Micro-styragel columns of 10,000, 1000, 500, and 100A pore sizes. Reported values were standardized against polystyrene. 

GPC analyses were performed with a Waters Model 244 chromatograph using Microstyragel columns. Both differential refractive index and UV (254 nm) detectors were used. THF was the eluant with a flow rate of 2 ml min-1. A benzene internal standard was employed to correct for flow variations and for normalization of the integrated peak areas. The column set was calibrated using nearly monodispersed polystyrene standards and all molecular data are reported as polystyrene-equivalent molecular weights. 

The chromatograph (Waters Associates) was fitted with PL Gel columns (Polymer Laboratories Ltd.) and two Infrared detectors in series. Chloroform was used as the eluant. Infrared detectors were used because the tin containing acrylic mommier has a characteristic carbonyl stretching frequency at 1620 cm which is well removed from that of other acrylic monomers which have, carbonyl absorptions at the more characteristic wavenumber 1720 cm . Both peaks obeyed the Beer Lambert law. A typical chromatogram showing the separation of residual monomers and polymer Is shown in Figure 1. 

Gel Permeation Chromatography. Samples were filtered on columns of Bio-Gel P-6DG (Bio-Rad Laboratories), and columns of Sephadex G-10, G-25, and G-50 (Pharmacia Corp.) using deionized water as eluant. Gel filtration properties are expressed in terms of the distribution coefficient calculated from the relationship = (V - V )/ (V - V ) where the the volume at which a component elutes, is the void volume, and is the total volume of the system. Blue dextran 2,000 and xylose were used to determine and Vj respectively. 

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