Linearity injection

Blends of sodium hypochlorite with 15% HC1 and with 12% HCl/3% HF have been used to stimulate aqueous fluid injection wells(143). Waterflood injection wells have also been stimulated by injecting linear alcohol propoxyethoxysulfate salts in the absence of any acid (144). The oil near the well bore is mobilized thus increasing the relative permeability of the rock to water (145). Temperature effects on interfacial tension and on surfactant solubility can be a critical factor in surfactant selection for this application (146). 

The Groton Biosystems protein analyzer tests injection reproducibility at three pressures (e.g., 25mbar at 0.2min, 50mbar at 0.1 min, and lOOmbar at 0.05min). Each injection pressure is injected five times and the complete injection linearity relative standard deviation (RSD) needs to be less than 5%. In addition, the carryover from successive injections is investigated. 

To ensure quantitative results it is essential that the instrument is capable of performing reproducible injections. Also, an evaluation of the injection linearity would be necessary to ensure that injections of different sample volumes can be related in a quantitative manner. 

FIGURE 6 Injection time linearity of an antibody molecule. Panel A e-gram for injection linearity. Panel B reduced SDS-PAGE Novex (8 I6% Tris-Glycine gel, Invitrogen, Carlsbad, CA). (See color plate 2.)... 

Figure 7 shows the results for the corrected peak area plotted against injection time for the HC, LC, and non-HC and LC species called non-main species. The corrected peak area values are used because they compensate for velocity differences between species of different molecular size as they pass through the detector. These results demonstrate that the reduced CE-SDS method has a wide injection linearity range (5—40 s at —5kV) for the HC, LC, and non-main species. 

Further analysis of linearity data typically involves inspection of residuals for fit in the linear regression form and to verify that the distribution of data points around the line is random. Random distribution of residuals is ideal however, non-random patterns may exist. Depending on the distribution of the pattern seen in a plot of residuals, the results may uncover non-ideal conditions within the separation that may then help define the range of the method or indicate areas in which further development is required. An example of residual plot is shown in Figure 36. There was no apparent trend across injection linearity range. 

Bacteriophage lambda (X) is a good example for considering phage infection. In lytic infection, the injected linear double-stranded X DNA first circularizes. It is then transcribed to produce viral proteins needed for viral DNA replication and packaging as well as many molecules of viral capsid proteins. The viral DNA is replicated and the DNA copies are packaged into new phage... 

The reproducibility of injection was demonstrated by repetitive injections (n=6) of a standard solution of corticosteroids at two different days. R.S.D. for retention times on day 1 and day 2 were 0.51 and 0.93, and for peak areas 2.49 and 1.78, respectively. The injection linearity in terms of analyte concentration and injection volume was also good (r > 0.998) [40]. Retention time and peak area reproducibility for corticosteroids extracted from urine was characterized by R.S.D. 2 and 7 % respectively [41]. Due to differences in UV transmission of the mobile phase, the baseline drifted with increasing acetonitrile concentration. 

An alkylamide arginine surfactant (where alkyl = Cio, C12, C14, C,g) was studied on a cyanoporpyl column (A = 210 nm) using a 42/58 water (0.075% TFA)/(80/20 acetonitrile/water with 0.1% TFA) mobile phase [1007]. All four components were baseline resolved in <13 min. Excellent peak shape resulted for a 1 pg injection. The colunm was severely overloaded at 25 pg injected. Linear ranges of 0.05-6 mM and detection limits of 0.007 mM (S/N = 3) were reported. 

LOD 75 pg injected Linear response over 4 orders of magnitude... 

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