Elution yield measurement

Elution Yield Measurement. The elution yield is defined as the ratio of the total eluted activity (TEA) measured under the defined experimental conditions described below to the maximum available activity, which is equivalent (taking into account the branching ratio) to the total parent activity (Q) present on the column at the time of elution. Different methods were... 

In some instances quantitation, or at least comparison of the proportions of the separated lipids, may be possible by scanning the plate directly by reflectance densitometry, e.g. after charring. Alternatively, the spot may be scraped off the plate and the colour or fluorescence of the eluted solution measured. The eluted compounds can be submitted to further analysis, by GLC for instance, to enable quantitation or identification. For reliable and meaningful results, known standards should always be run and analysed under identical conditions because of variable colour yields with different lipids. Even so, results obtained by different methods will often vary. 

The elution yield and iron breakthrough were measured as a function of time and number of elutions. Six elutions were performed over a period of 26 hours and gave essentially constant Mn-52m recovery, averaging 93% of the available radioactivity. 

Among the many potential eluants tested, only mineral acids and aqueous solutions of alkaline and ammonium carbonates yielded measurable elution efficiencies. While carbonates require higher concentrations and temperatures, dilute mineral acids turned out to be quite effective even at room temperature. Figure 8 shows six loading-elution cycles starting with a uranium content of the resin of 110 ppm. 

In the Rf experiments performed at the PSI Philips Cyclotron [40], Rf was produced in the " Cm( 0,5n) reaction at 100 MeV. The target contained 10% Gd enriched in Gd to produce simultaneously short-lived Hf isotopes. They were used to monitor the behavior of Hf and to perform yield measurements by y spectroscopy. Rf and Hf were transported by the He(KCl) gas-jet and were collected for 90 s by impaction inside ARCA II [40]. The deposit was dissolved in 200 pL 0.1 M HNO3/X M HF x variable) and was fed onto the 1.6 mm i.d. X 8 mm cation-exchange column at a flow rate of 1 mL min The effluent was evaporated to dryness as sample 1. In order to elute remaining Rf and Hf from the column, a second fraction of 200 pL 0.1 M HNO3/O.I M HF was collected to strip all group-4 elements from the column. The fraction was prepared as sample 2. 

Fig. 17. A schematic of the alkane line obtained by inverse gas chromatography (IGC) measurements. The relative retention volume of carrier gas required to elute a series of alkane probe gases is plotted against the molar area of the probe times the. square root of its surface tension. The slope of the plot is yielding the dispersion component of the surface energy of...

To assay the amount of LBP, first an excess amount of luciferin is added to the sample at pH 8 to saturate the binding site of LBP, and then the excess luciferin is removed by gel filtration using a small column of Sephadex G-25 (about 1 ml volume) also at pH 8. The luciferin-bound LBP is eluted at the void volume. To measure the amount of LBP, the following assay buffer is added to a small portion of the elu-ate 0.2 M phosphate, pH 6.3, containing 0.25 mM EDTA, 0.1 mg/ml of BSA, and luciferase (Morse and Mittag, 2000). The total light obtained represents a relative amount of LBP the absolute amount (the weight or the number of molecules) cannot be obtained because the quantum yield of the luminescence reaction is not known. 

A red solution of 0.1 to 0.2 mmol of ( + )-(.9)-l2 (R = CH3) in 5 mL of toluene and an ampule with an 0.3-1.2 mmol amount of BF, are placed into an autoclave, which has been flushed with CO as described above. When the CO pressure is increased to 3.0 xlO5 Torr, the ampule bursts. After 16 h at r.t., the concentrated yellow solution is chromatographed. F.lution with toluene indicates that there is no remaining starting material. Elution with (C2H5)0 yields the desired (-)-(/()-13 yield 44-55% op 92% (determined by measurement of the optical rotation). 

Although the decomposition of a data table yields the elution profiles of the individual compounds, a calibration step is still required to transform peak areas into concentrations. Essentially we can follow two approaches. The first one is to start with a decomposition of the peak cluster by one of the techniques described before, followed by the integration of the peak of the analyte. By comparing the peak area with those obtained for a number of standards we obtain the amount. One should realize that the decomposition step is necessary because the interfering compound is unknown. The second approach is to directly calibrate the method by RAFA, RBL or GRAFA or to decompose the three-way table by Parafac. A serious problem with these methods is that the data sets measured for the sample and for the standard solution should be perfectly synchronized. 

Detection and quantification of protein by measuring absorbency at 280 nm is perhaps the simplest such method. This approach is based on the fact that the side chains of the amino acids tyrosine and tryptophan absorb at this wavelength. The method is popular, as it is fast, easy to perform and is non-destructive to the sample. However, it is a relatively insensitive technique, and identical concentrations of different proteins will yield different absorbance values if their content of tyrosine and tryptophan vary to any significant extent. Hence, this method is rarely used to determine the protein concentration of the final product, but it is routinely used during downstream processing to detect protein elution off chromatographic columns, and hence track the purification process. 

The supernatant was collected and applied to a Q Sepharose column. The column was washed with buffer A and bound proteins were eluted with a gradient of buffer A to buffer B. Activity (measured as described in step 5) eluted at 100-150 him (NH4)2S04 and active fractions were pooled, yielding a pure protein as judged by SDS-polyacry-lamide gel electrophoresis. 

Yield. The Rb-82 content of 50 ml of eluate, decay corrected to end of elution, collected at 50 ml/min is measured in a Capintec CRC-17 dose calibrator using the potentiometer setting recommended by the manufacturer for Rb-82. While this datum is not as significant as the dynamic yield information obtained from measurement of elution profiles, it is valuable in preliminary development work and in monitoring the performance of a given unit through an extended use period. 

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