Percent peak area

Once an appropriate, MS-friendly, LC method is developed, information such as the UV spectrum and percent peak area can be used to establish peak correlation between LC/UV and LC/MS methods. 

Hydrodynamic injection was compared with electrokinetic injection (data not shown). The two injection modes gave comparable percent peak areas. Electrokinetic injection gave slightly higher resolution compared to hydrodynamic injection. For the CE-SDS method, electrokinetic injection is generally recommended. 

Tijp 3/2 binding energies (eV) and percent peak area of the two component peaks for TS-2 cat ysts before and after acid leaching. 

Average (n=2) percent peak area from GCMS data. 

Substrate Percent peak area of comonent peaks Temp. ( C) 1 2 3 4 5... 

Source FromMervat, M.,Soliman, A.,Osman,F.,andEl-Sawy,A.,Agnc. BioL Chem.,45,2123,1981. Percent peak area. 

HPLC assay The purity of the final combinatorial products is determined by the aforementioned gradient HPLC method. The library samples before and after extraction are injected onto the HPLC system. The product and impurity peak areas are then compared to assess the product purity and recovery. The product purity is determined by the percent peak area of the product of interest in the post-extraction sample solution. The product recovery and the removal of the excess reagents, by-products, or impurities are evaluated by the ratio of the peak areas of the respective component before and after extraction. 

Where SA R is the specific area of the reference peak, and SA is the specific area of component x. AR is the GC peak area of the reference, Ax is the GC peak area of component x, WR is the weight of the reference, and Wx is the weight of component x. The weight percent of component x can be obtained from the sample chromatogram by using the relative response factors in the following equation ... 

A rough estimate of the concentrations of components in a mixture can be obtained using peak areas. This method assumes that the area percent is approximately the weight percent. The area of each peak is divided by the sum of the areas of all peaks,... 

Treatment Sample Percent label claim by peak area (w/v) Percent label claim by peak height (w/v) Mw (1 x 104) Hi (1 x 104) P... 

As with any analytical instrumentation that incorporates an autosampler, it is essential to evaluate the percent carryover obtained for a particular analyte under particular rinsing conditions. For these evaluations, a cartridge packed with a C18 stationary phase (80 x 0.5 mm/column) was employed. Gradient and detection conditions were the same as those described for the evaluation of retention time and peak area reproducibility (see Section 6.3.2). 

A data processor plots the chromatogram, automatically integrates the peak areas and prints retention times, percent areas, baseline drift and attenuation for each run. It also computes blank values, constant factors and relative average elemental contents. 

The precision of the assay for nonreduced samples was demonstrated by the evaluation of six independent sample preparations on a single day (repeatability) and the analysis of independent sample preparations on three separate days by two different analysts (intermediate precision). The RSD values for the migration time were 0.9%. The RSD values for peak area percent of the main peak and the minor peaks in the profile were 0.6 and 12.6%, respectively. The higher variability observed with the minor peaks was determined to be primarily related to the sample heating during preparation for the analysis. These results demonstrate that the use of uncoated fused-silica capillaries in combination with a sieving matrix can provide adequate precision and analyte recovery. 

FIGURE 18 A challenging case in which peak correlation between two LC methods cannot be achieved based on the percent of peak area and the UV spectra of the peaks (courtesy ofWaters Corp.). 

Integration of the electropherogram for an antibody to quantify main protein species percent light chain and heavy chain (%LC and %HC) and minor species such as percent non-main and percent high molecular weight species (%non-main species and %HMW) is shown in Figure 5. Corrected peak areas were used for quantification. The % corrected peak area is defined as ... 

To further confirm the ability of the reduced CE-SDS method to be used for determination of purity, percent corrected peak area (%HC, %LC, and %non-main) was calculated for each component with respect to the total corrected peak area. Eigure 8 presents the relationship between %HC, %LC, %non-main species, and injection time. 

The % corrected peak area values are shown in Table 2. When an injection time of 20 to 40 sec is used, the assay generated reasonable precision. The overall percent relative standard deviation (%RSD) are 0.7, 1.6, and 7.6 for the HC, LC, and non-main species, respectively. The %RSD of HMW species is relatively high due to poor resolution between the HMW and HC peaks. In this case, we recommend that the HMW species not be integrated separately from the HC component unless there is a clear graphic valley point for integration. 

System suitability errors often include profiles that are not consistent with historical data such as (1) excessive peak tailing, poor resolution of critical components or noisy baseline (2) peak spikes due to micro bubbles or electric shock and (3) integration parameters such as percent main peak area out of range for the assay reference control sample. 

In DSC measurements, the weight percent of a phase was calculated using the peak area of the DSC curve and its reported heat of formation. For example, weight percent of the p-MgHj in a reactively milled powder can be estimated using the peak area of the DSC curves and the reported P-MgHj heat of formation (-74 kJ mol [175], which equals to -2,811 J g ). The DSC curve was analyzed by the NETZSCH thermal analysis software. First, the onset and end temperature of the peak were determined. Then, the peak area was calculated using the linear approach from the onset temperature to tlie end temperature (Fig. 1.37) by the DSC software. 

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