Elution, column

A conventional chromatographic technique utilizing an instrument at least equal in performance to the highest sensitivity range of the Perkin Elmer Vapor Phase Fractometer Model 154 shall be used. A two meter elution column... 

The liquid-liquid partition procedure described above can be substituted by using a Chem Elut column. After concentrating the extract derived from Section 2.2 to 20 mL, the concentrate is applied to a Chem Elut column and charged at room temperature for 5-10 min. Naproanilide, propanil and mefenacet are eluted with 80 mL of n-hexane when using the Chem Elut column. The recoveries are in the range 96-110% (personal data). 

The other column chromatography cleanup procedure uses a macroporous diatoma-ceous column (e.g., Chem Elut column) and an SPE column Cig cartridges are effective columns for sample cleanup. 

Macroporous diatomaceous column (e.g.. Chem Elut column). The combined soil extract is concentrated to dryness under vacuum, the residue is dissolved in 15 mL of water and the solution is applied to a Chem Elut column. After charging for 20 min, acetamiprid is eluted with 100 mL of dichloromethane. The eluate is evaporated to... 

SPE column Cis cartridge. The concentrated eluate from the Chem Elut column as described above is dissolved in 5 mL of distilled water and charged on a Cig cartridge pretreated with 20 mL each of methanol and distilled water. Acetamiprid is eluted with the 30 mL of 15% acetonitrile solution and the eluate is collected and concentrated to dryness at 40-50 °C under vacuum. The residue is dissolved in a suitable volume of acetone and analyzed by GC. ... 

Centrifuge tubes Becton-Dickinson BlueMax polypropylene, 15-mL SPE column adapters for 1-, 3- and 6-mL Bond Elut columns SPE plastic reservoirs 75-mL Disposable flow control valve liners for SPE... 

Elute column with 10 MNaCl or dilution buffer. 

Figure 6.3 Nonspecific protein adsorption as a result of column degradation. White circles indicate eluted column peak heights of a new column. Black diamonds indicate eluted peak heights after the column was treated with 50 wash cycles. See text for discussion. (Data from P. Gagnon, 1997, Validated Biosystems Quarterly Resource Guide for Downstream Processing, 2(1), 1, http //www.validated.com/revalbio/library.html.)...

Saponification extraction using a Chem Elut column, semi-preparative HPLC (Lichrosorb Si 60, 250mmx4.0mm, 5pm)... 

Determination of column stability test the column stability by applying a known amount of analyte perform sample loading, column wash, analyte elution, column regeneration, and storage cycle steps for multiple analyses. Initially we test the columns reusability daily for a week, then weekly for a month, then monthly for up to 3 mo. 

Figure 12. Reequilibration of columns with micropellicular or porous stationary phases during gradient elution. Columns Micropellicular, Hy-Tach C-18 silica, 135x4.6mm porous, Vydac, C-4 silica, 135x4.6mm flow rate, 1.0 ml/min. temp., 80oC. Eluents were same as described in Figure 10. The columns were first equilibrated with 90% B and reequilibration was begun by a sudden drop in the concentration of B eluent to 22% in 0.1 min. Retention time of ribonuclease A was measured by gradient elution (22 to 90% B in 5 min) during column regeneration.

Fig. 10.17. Capillary electrochromatography of PTH-amino acids with gradient elution. Column, 207 (127) mm x 50 pm i.d. packed with 3.5 pm Zorbax ODS particles, 80 A pores. Starting eluent (A), 5 mM phosphate, pH 7.55, 30% acetonitrile gradient former (B), 5 mM phosphate, pH 7.55, 60% acetonitrile flow-rate (through inlet reservoir), 0.1 ml/min gradient, 0-100% B in 20 min voltage 10 kV current, 1 pA temperature, 25°C UV detection at 210 nm electrokinetic injection, 0.5 s, 1 kV. Peaks in order of elution formamide PTH-asparagine PTH-glutamine PTH-threonine PTH-glycine PTH-alanine PTH-tyrosine PTH-valine PTH-proline PTH-tryptophan PTH-phenyialanine PTH-isoleucine PTH-leucine. The concentration of the PTH-amino acids dissolved in the mobile phase was 30-60 pg/ml. Reprinted with permission from Huber et al. [68]. Copyright 1997 American Chemical Society.

Elution. After the actinides have been loaded and the resin washed, the (short) loading column effluent is routed to the (long) separation column, and the high-pressure pump is used to transfer eluent through the columns at a rate of 1.0 L/h (a superficial velocity of 2.0 mm/s through the elution column). 

Typical "plant equipment is shown in Fig. 3. The equipment racks are assembled and tested before being installed in hot cells. This rack, which served for some five years, has one high-pressure pump, a short "loading column, two long elution columns, and appropriate associated valves, feed vessels, product collection apparatus, and plumbing. Resin was periodically replaced by hydraulic transfer. 

Adjust 20 ml of urine to pH 5 with 0.1 M hydrochloric acid, add 2 ml of acetate bi er (pH 5), and 10 000 Fishman units of mixed gluciwoiiidase/ sulphatase (from. Helixpomatid), and heat in a water-bath at 60° for 2 hours. Pom tiie urine on to Ml imbuffered Tox Elut column (see Reagent. / ipendix) and leave for 2 to 3 minutes to allow the sMnple to soak into the column. Place a 50-ml test-tube under the coliunn outlet and pour on to the coliunn 20 ml of a mixture of chloroform isopropyl alcohol (9 1). When the elution is complete, insert into tile top of the column a hollow rubber stopper... 

Chromatographic analysis times are rapid and after gradient elution column reequilibration time is short. 

Fig. 1.13. Separation of a product of partial transesterificaiion of rapeseed oil with methanol using combined RPC and NARPC gradient elution. Column Separon SGX Cm, 7 pm, 150 x 3 mm i.d. Ternary gradient from 30% A + 70% B to 100% B in lO min and to 50% B -t- 507r C in 20 min. followed by isocratic elution with the final mobile phase composition for 5 min, at I ml/min. Injection volume 10 pi. UV detection at 205 nm. Notation of sample compounds Ln. L, O and G are used for linolenic acid, linoleic acid, oleic acid, gadoleic acid, respectively, and for their acid parts in mono-, di- aixl tri-acylglycerols and methyl esters Me means methyl in methyl esters.

Loading and elution column solution forward flow to fluidize the resin in each column, valve 1 open, valves 2, 3, 4, 5, and 6 closed. (2) No solution flow, resin settling, valve 2 open to return feed solution to storage, valve 1 closed. (3) Solution back flow, resin from bottom stage transferred to resin transfer vessels, valves 2, 3, 4, 5, and 6 open, valves 1 and 3 closed. (4) Valve flush and resin transfer from resin transfer vessels to top offluid bed columns, no forward solution flow, valves 1, 3, 4, and 5 open, valves 2 and 6 closed. (5) Resumption of solution forward flow to the fluid bed columns. 

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