Solution injection

Electrokinetic injections are made by placing both the capillary and the anode into the sample vial and briefly applying an electric fleld. The moles of solute injected into the capillary, nj, are determined using... 

In addition to the normal problems of completely dissolving particles of water-thickening polymers, xanthan gum contains insoluble residues which decrease polymer injectivity. Various methods of reducing insolubles content and improving xanthan solution injectivity are available (80—87). None appears economically viable. Oxygen scavengers (88) and bactericides (77,89) are commonly used to stabili2e injected polyacrylamide and xanthan gum solutions (90—102). 

Small particle size resins provide higher resolution, as demonstrated in Fig. 4.41. Low molecular weight polystyrene standards are better separated on a GIOOOHxl column packed with 5 /u,m resin than a GlOOOHg column packed with 10 /Ltm resin when compared in the same analysis time. Therefore, smaller particle size resins generally attain a better required resolution in a shorter time. In this context, SuperH columns are best, and Hhr and Hxl columns are second best. Most analyses have been carried out on these three series of H type columns. However, the performance of columns packed with smaller particle size resins is susceptible to some experimental conditions such as the sample concentration of solution, injection volume, and detector cell volume. They must be kept as low as possible to obtain the maximum resolution. Chain scissions of polymer molecules are also easier to occur in columns packed with smaller particle size resins. The flow rate should be kept low in order to prevent this problem, particularly in the analyses of high molecular weight polymers. 

GFRP tolerandng glass fiber reinforced plastic IBM construction solutions injection blow molding... 

Injection 5 pi of petroleum ether solution Injection port temperature 250°C Detector temperature ... 

Figure 9 shows the result of injecting 10 gA of the total low molecular weight fraction from GPC 1 (Column Code A2) into GPC 2 (Column Code Bl). With this column code, GPC 2 is performing as a High Performance Liquid Chromatograph (HPLC). Separation is based upon solubility (i.e. composition differences) rather than upon molecular size. Methyl methacrylate monomer was used as a reference and added to the solution injected into GPC 1. Concentrations of n-butyl methacrylate, styrene and conversion are readily calculated from the peak areas and initial concentrations. 

In the extensive literature on polymer drag reduction, it has occasionally been reported that a continuous thread of a high-concentration polymer solution injected into the axis of a pipe produces a drag-reduction effect on the water flow in the pipe [856]. The thread seems to persist through the length of the pipe and little, if any, diffusion of polymer to the walls of the pipe is apparent. 

Quantitative analysis is performed by the calibration technique. A new calibration curve with a standard solution of each diphenyl ether herbicides is constructed, plotting the peak area against the amount of standard solution injected. Each diphenyl ether herbicide in the sample is measured by using the peak area for each standard. Before each set of measurements, the GC and HPLC system is checked by injecting more than one standard solution containing ca 0.01-2 mg L of each compound. 

Limit Concentration of Monomers in Solution In the calcic environment considered, the CMC values of surfactants are low. For example, sulfonate and Genapol solutions reach their CMC at 30 ppm (Table II). The surfactant solutions injected in practice at concentration of about one or several percent are thus generally used well above their CMC. Under such conditions, the predominant fraction of each surfactant is the micellar form whose composition (xj) is practically equal to the initial proportion of products (i.e. alpha 1 for sulfonate). At this concentration level of products, very small proportions of monomer species coexist, the limit concentrations of which are respectively ... 

The use of electrically-gated solute injection into the electrophoresis system simplifies the chip design as electrical connections are easy to implement as compared to the microfluidics part of the chip. Voltage waveform manipulation via hardware and software are relatively easy to control and implement. 

Figure 12 Separation of Irganox 1076 and Irganox PS802 by size exclusion chromatography (duplicate solution injections of each antioxidant showing the reproducibility of the technique).

Fukishi and Hiiro [222] determined sulfide in seawater by this technique. The method is based on the generation of hydrogen sulfide by the addition of sulfuric acid to the water sample. The gas permeated through a microporous polytetrafluoroethylene (PTFE) tube, and was collected in a sodium hydroxide solution. The carbon dioxide in the permeate was removed by adding a barium cation-exchange resin to the sodium hydroxide solution. Injection into the... 

Halliday et al. [396] have described a simple rapid graphite furnace method for the determination of lead in amounts down to 1 xg/l in polluted seawater. The filtered seawater is diluted with an equal volume of deionised water, ammonium nitrate added as a matrix modifier, and aliquots of the solution injected into a tantalum-coated graphite tube in an HGA-2200 furnace atomiser. The method eliminates the interference normally attributable to the ions commonly present in seawater. The results obtained on samples from the Firth of Forth (Scotland, UK) were in good agreement with values determined by anodic stripping voltammetry. 

Flow rate The limitations associated with the volume of flow cell can be overcome by accurately controlling the flow rate of each stream entering into the manifold. This experimental parameter controls the residence time of the chemiluminescent solution within the cell and can be easily optimized by the operator. How rates are directly proportional to the rate of the CL reaction. As the rate of the reaction increases, the flow rate should be increased but, at the same time, consumption of reagents increases. The flow rate also affects the shape and the height of the peak as well as the measurement rate (number of sample or standard solutions injected per hour). 

Volume of analyte injected As the volume of sample and standard solution injected increases, the peak height and duration increase. Nevertheless, if the volume increases too much, dispersion of the carrier into the analyte is limited and the concentration gradient within the flow is distorted resulting in very high dispersion values at the edges and very low values in the center. As a result, double peaks are recorded that are not appropriate for analytical measurement. 

Viscose Also known as the Cross-Bevan-Beadle process. A process for making regenerated cellulose fibers. The product has been known by the generic name rayon since 1924. Cellulose, from cotton or wood, is first reacted with sodium hydroxide ( mercerization), yielding alkali cellulose. This is dissolved in carbon disulfide, yielding cellulose xanthate, which is dissolved in sodium hydroxide solution. Injection of this solution (known as viscose... 

The physical size of a peak, or area under the peak, traced on the chromatogram is directly proportional to the amount of that particular component passing through the detector. This, in turn, is proportional to the concentration of that mixture component in the sample solution. It is also proportional to the amount of solution injected, since this too dictates how much passes through the detector. The more material being detected, the larger the peak. Thus, for quantitative analysis, it is important that we have an accurate method for determining the areas of the peaks. 

Cosolvent flooding is accomplished by the introduction of a cosolvent solution, with subsequent extraction of contaminated groundwater and NAPL. In one reported field test study that focused on enhanced dissolution, the use of about nine pore volumes of a 70% ethanol, 12% pentanol solution injected into a test cell resulted in about 81% bulk NAPL removal, with a higher removal efficiency for several other individual compounds. In another field test study, where mobilization removal was emphasized, injection of about four pore volumes of a mixture of tert-butanol and w-hcxanol into a test cell resulted in the removal of about 80% of the bulk NAPL, and higher removal efficiency of the more-soluble NAPL compounds. 

Sample solution injections at 100% w/w level for purity determinations... 

Sample solutions injections at 10% w/w level for assay determinations... 

The sequence is started and ended with the injection of a selectivity batch solution. After each 10-sample solution injection the selectivity batch solution is re-injected. The result is qualitatively evaluated. In order to demonstrate the run-to-run variability, the selectivity is checked on at least three different capillaries by at least triplicate injections of a selectivity batch solution on each capillary. The result is qualitatively evaluated. As can be observed in Figure 11, the separation is nicely reproducible on three different capillary columns for the same intermediate of nebivolol. 

The volume of solution injected, up to 2 ml, appeared in itself to be unimportant in producing lethality in mice although most of the subjects had obvious discomfort for 30 minutes or so. Normal saline in doses of 1.0-2.0 ml produced a comatose condition in all animals at the highest dose, 2 of 6 subjects did not survive the experimental procedure. 

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