Peak Profile Explained = iChemExplorer creates Peak Profiles from chromatographic data in the window under the iGraph tab. A Peak Profile sets points along a line by the area percent of that peak in the sample. Each line corresponds to a different peak. Consider that a reactant starts near 100 % with the first sample and that with each successive peak the area percent declines as the reactant is consumed. In this way a line is defined as that starts in the upper left hand corner and declines to the lower right hand corner. In this way data from a large number of chromatographs may be displayed on a single graph. The profiles for each peak are color coded according to the legend in the window with the peak time.
How to visualize data - Open iChemExplorer. Select Load HPLC Data button. A Windows Explorer window opens. Open the subdirectory with the data folders that contain the sample data. Open a folder in the subdirectory and highlight a *.csv file. Select open. iChemExplorer automatically opens all the other data folders in the subdirectory and loads the matching file name. iChemExplorer automatically assigns an identify to the sample according the auto-prefix created by the HPLC Control application such as Agilent ChemStation. The peak profile appears in the window.
How to select a vial to view - Look at the tray grid on the left side of the screen. The locations in white indicate that the associated data may be displayed. Move the cursor to the location to view point profile in iGraph window.
How to exclude sample data - Move the cursor to the iGraph window. Right-click to disclude data points for sample from peak profile. An alternate is to select the sample number from the Exclude box in the lower left hand corner. To return the data to the profile either right click at the sample point on the iGraph window or deselect from the Exclude box.
How to view chromatographs - Move the cursor to the iGraph window. Left-click to open a window to view the chromatographs. Use the Scroll Through button to view a movie of the successive chromatographs. Select Next or Previous to view each chromatograph individually. Select Copy to Clipboard to paste to any Windows compatible application.
How to set threshold and tolerance - Threshold sets the minimum area percent to display in the iGraph window. Tolerance sets the separation required to differentiate one peak next to another. Higher values show fewer lines in the peak profile. While the defaults area good rule of thumb, please play with these values to best view your data. The choices do not affect the underlying chromatographs.
How to name, color and hide peaks - From the top bar select Edit and then Peak Names. A window opens that lists each of the peaks displayed. Enter a name and select a color to reset the peak profile. Select Hide to remove the line for that peak from the iGraph window. Select the buttons at the bottom to recalculate the profile with only the peaks displayed. Select Apply and leave the window open or select Close to apply the setting and close the window.
How to rescale peak profile - Enter values in the minimum and maximum boxes for the x-axis and y-axis as desired. Select Time in minutes or hours to scale. The x-axis scales in multiples of 9 - 900 minutes for example. Deselect auto scale. The x-axis is rescaled by time.
How to overlay peak profiles - Select Enable Overlay Mode. Select vial locations. The peak profile for each vial selected is overlaid one on another. The colors are the same for matching peak times. This overlay may be copied to clipboard to paste in any Windows compatible application. To eliminate overlay deselect Enable Overlay Mode. Select a vial location. The overlay is removed.
How to export to Excel - With the peak profile in the iGraph window will all changes desired select the Save Collated Report button. A Windows Explorer window opens to name and locate the *.xls file. Select Save. The Excel file is automatically created. Open the file. The first tab holds the peak profiles for each vial. The second tab holds the first, mid and last chromatograph for each vial. The succeeding tabs hold the peak profile for each vial separately per tab. The last tab holds the collated data for all the chromatographs as numerical values for storage and further analysis.