HPLC chromatograms evaluation

FIGURE 8 HPLC chromatograms used for the evaluation of the autosampler. Upper 80 injection of ethylparaben. Lower 80 jiL injection of the mobile phase. 

Two different chiral HPLC systems have been developed in this laboratory to evaluate the enantiomeric purity of brinzolamide. The operating conditions for these methods are also summarized in Table 9. Figure 15 shows a chiral HPLC chromatogram using the second set of conditions listed. 

The manual investigation and interpretation of such complicated chromatograms is a very time-consuming enterprise. To facilitate the evaluation of HPLC-chromatograms there are several software-aided methods available, the two main methods being the extract-ion -function and the landscape -plot. 

In a HPLC chromatogram under an incompletely resolved peak, polycyclic aromatic hydrocarbons (PAHs) are expected. Since detection was based on a diode array detector, the observed peak can be evaluated at several wavelengths. The spectrochromatogram for five wavelengths and seven retention times is shown in Figure 5.8. The corresponding data are given in Table 5.3. 

Reference has already been made to the broader spectrum of resin components extracted under supercritical conditions. A comparison of HPLC chromatograms (Figure 4.6) shows only minor differences. It has not been determined which of the hard resins contribute to the lead conductance valve, enhancing the apparent efficiency of supercritical CO2 compared with liquid CO2 if this method of analysis is used for evaluation. If both hops and extract are analysed by HPLC, there is no difference in efficiency of extraction between the two media. 

Figure 8 shows the 259 nm UV record from the gradient elution of the mixture of three samples containing 46.6, 57.3, or 77.9 wt % methyl-acrylate units. This was the first report on copolymer separation by HPLC 38). The chromatogram was obtained on a silica column (600 x 7.5 mm, d0 = 5 nm dP = 15 pm) with a CCU/methyl acetate gradient (7-35 % in 35 min). In spite of the decaying activity of the column the composition distribution of the 57.3% sample could be evaluated. 

Since the work of Manley and Shubiak (182), who were the first to apply HPLC to anthocyanin analysis, numerous HPLC techniques have been developed for the separation and quantification of anthocyanins and anthocyanidins. Nowadays HPLC has become the method of choice, because it offers the advantage that it is a rapid, sensitive, and quantitative method. For the peak identification and quantitative evaluation of chromatograms, the use of pure anthocyanin standards is recommended however, only a limited, but constantly increasing, number of substances is avail-... 

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