Spin-column chromatograph

Remove excess reagent and reaction by-products by dialysis or gel filtration using 0.1M sodium phosphate, 0.15M NaCl, lOmM EDTA, pH 7.5. For chromatographic separation, use a desalting gel filtration support such as the Zeba desalting spin columns (Thermo Fisher) or the equivalent. The SAMSA-modified protein may be stored at -20°C until needed. 

Comparison of CPC Spin Column/HPLC ESI-MS with Tandem Chromatographic Method of CPC/HPLC ESI-MS... 

In principle, the analytical results obtained by the GPC spin column/HPLC ESI-MS methodology described in this chapter should be similar to the results obtained using the tandem chromatographic method of GPC/reversed-phase HPLC ESI-MS described in Chapter 3. There are practical advantages for each method. Since each of the chromatographic and mass spectral steps are done serially for the GPC spin column/HPLC ESI-MS methodology, each of the steps can be performed and optimized individually. In the event of mass spectrometer failure, the production of spin column eluate samples can proceed and samples can be stored for future analysis. In contrast, the parallel methodology of tandem GPC/ reversed-phase HPLC ESI-MS requires the simultaneous optimization of multi-... 

Pure (A)-1 -chloropropene was obtained by careful distillation of a mixture of (E)- and ( )-l -chloropropene (available from Columbia Organic Chemicals Company Inc.) using a Nester-Faust Teflon annular spinning band column [(Z)-l-chloropropene has b.p. 33° (A)-l-chloropropene has b.p. 37°]. Small quantities of powdered sodium bicarbonate and hydroquinone (1,4-benzenediol) placed in the distillation flask inhibit acid-catalyzed isomerization and polymerization. Gas chromatographic analysis of the material used in these experiments on a 4-m., 15% l,2,3-tris(2-cyanoethoxy)propane (TCEP) on Chromosorb P column, operated at room temperature, typically indicated that it had isomeric purity >99.9%. (A)- 1-Chloropropene is stable for several months at room temperature, but it should be stored in a cool place. 

Solubility of polymers in tetramethyl ammonium hydroxide aqueous solution was measured by dipping the wafer on which the polymer solution was spin-coated, for 1 min. at 25°C. The prebake was carried out at 90°C for 5min. Sensitivity of resists was measured after the exposure with CA 800(Cobilt) or KrF excimer laser(0.9mJ/cm2/1 pulse). The polymer structure was determined by iH-NMR, 13C-NMR(FX90Q apparatus,JEOL) and 2 Si-NMR. The molecular weight distribution was determined with a Toyo Soda Model 801 gel permeation chromatograph at 40°C. The four columns were connected in series, each packed with G-2000H8x3 and G-400H8(Toyo Soda polystylene gel), respectively. 

A Nester-Faust Model NFT-50 annular spinning-band distillation unit was used to obtain the reported product yields in >99% chemical purity by gas chromatographic analysis (Perkin-Elmer Model Sigma IB Instrument using a 6 x 1/8" 5% SE-30 on silylated Chromosorb W column). Lower product yields (84-86%) of similar chemical purity were obtained using a 200-mm column packed with glass helices. 

Infrared spectra were determined using Perkin-Elmer infrared spectrophotometers models 137-B and 21. NMR spectra were run using Varian T-60 and A-60 spectrometers. Gas chromatographic analyses were done on a Hewlett-Packard model 5750B instrument. Fractional distillations were performed on a Nester-Faust 18-inch semimicro spinning band column equipped with a stainless steel band. 

If the retention times of the analytes are known, or there is an efficient method for their detection on-line, such as UV, MS or radioactivity, stop-flow HPLC-NMR becomes a viable option. In the stop-flow technique, all the usual techniques available for high-resolution NMR spectroscopy can be used. In particular, these include valuable techniques for structure determination such as 2-dimensional NMR experiments which provide correlation between NMR resonances based on mutual spin-spin coupling such as the well-known COSY or TOCSY techniques. In practice, it is possible to acquire NMR data on a number of peaks in a chromatogram by using a series of stops during elution without on-column diffusion causing an unacceptable loss of chromatographic resolution. 

Product Evaluation. Gaseous products were analyzed by gas chromatography (GC) using an alumina column. Liquid products were evaluated by physical properties, elemental analysis, liquid chromatographic separation (9), and simulated distillation (10). Distillation to produce a gasoline fraction was accomplished with a spinning band distillation column. Gasoline analysis and evaluation was obtained from an industrial analysis laboratory. 

The rate of elution of a component of the mixture is determined by the relative affinities of the component for the stationary and mobile phases. In gas chromatography, the elution rate is most often expressed as a retention time, defined as the time between the placement of the sample on the column and the maximum elution of the component in question. The basic principle responsible for the great utility of all chromatographic methods is the same Even compounds with very similar structural features frequently are eluted from the column at sufficiently different rates that an analytical or preparative separation is possible. If the efficiency of a gas chromatographic column is expressed in theoretical plates for comparison with distillation (Sec. 2.4.1), it is found that the gas chromatographic column provides 50 times as many theoretical plates as an efficient distillation column (e.g., a spinning-band column) of the same length. 

Fig. 8. The motion of a spin label incorporated into the polar lipids of chloroplast membranes from N. oleander as a function of temperature. The polar lipids were prepared from a total lipid extract of chloroplast membranes by chromatographic separation of the neutral lipids on a silicic acid column. The lipids were suspended in 0.01 M Tris-acetate buffer, pH 7.2, containing 5 mm EDTA, and vesicles formed by brief sonication. The vesicles (1 mg lipid/O.I ml) were labeled with 12NS, and the motion is expressed as roan empirical motion parameter which approximates the time for the N- 0 band of the probe to rotate through 90°. The motion of the spin label increases i.e., to decreases, as the temperature increases. The temperatures of 53°, 49°, and 43°C correspond to the temperature at which fluorescence intensity increased (see Fig. 7) for plants grown at 45°/30°C (circles), 20715°C (squares), and 24 h after plants acclimated to 45°/32°C were shifted to 20°/15°C (triangles). The straight lines were fitted by linear regression and the value for to at 53°, 49°, and 43°C are 8.6, 8.8, and 8.4 0.05 x I0 s, respectively.

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