This plotting calculator was developed in order to help chromatographers compare HPLC columns based on their characterization using the Hydrophobic Subtraction Model(HSM). The graph compares the chosen columns to all other columns in the database. Additional filters can be added to narrow down the number of columns compared. On the graph, the black marker indicates the properties of the chosen column. All other columns compared are shown in colors according to their Fs value, with low Fs values in red or orange and high Fs values appearing in blue or purple.

Using the Comparison Plot

  1. Choose a Column to Compare

    This column will be compared to the other columns selected from the database. Clicking on the desired option should select the appropriate column

  2. Select Fs Weighting Factors (Optional)

    Although the values pre-selected by the website are chosen based on the original HSM values used when the equation parameters were characterised, the weights can be changed depending on the importance of each parameter to your experiment. The values can be changed by clicking on the box and typing in a new value.

  3. Filtering Columns for Comparison (Optional)

    Should you only want to compare the selected column to a small group of other columns, the options can be narrowed down according to the options shown in each box. Clicking on one option will filter the full dataset to include only columns with that particular property. Dragging the mouse will select more than one option and the data will be filtered to include columns that adhere to any one of those parameters. Disjointed filter options can be selected by holding CTRL and clicking on the desired filter parameters. At any time all selected options in one box can be removed by clicking the "remove filter" option and all filters will be removed by clicking the "remove all filters" button.

  4. Reading the Graph

    On the graph, the black point shows the properties of the column selected for the comparison. All other points on the graph are colored according to their Fs value, with red indicating a low Fs value and purple indicating a high value. For more information, a bar showing the correlation of Fs value to color is shown to the left of the graph. Additonally, the parameters used in the final calculation are shown at the bottom of the graph, in the form of labeled radio buttons. To view the graph according to a different set of parameters, just select one of the other radio buttons.

  5. Manipulating the Plotly Plot

    All manipulations to the graph can be made to the plot using the mouse and menu options in the top right corner of the plot itself.
    The camera button will download a snapshot of the graph as a png file.
    The floppy disc icon allows the plot to be saved with Plotly and edited using their website.
    Selecting the magnifying glass icon allows you to zoom in and out of the plot using the mouse. Once selected, clicking and dragging the mouse down will zoom into the middle of the image. Dragging up will zoom out.
    The four sided arrow icon allows you to pan within the plot. Click and drag in the direction that you would like to view.
    The twisted arrow icon allows you to rotate the graph with the center of the shot as the axis of rotation. Select, then click and drag in the direction you would like to rotate
    The Z and the home icon both reset the graph to its default settings, and the video recorder icon resets the graph to your last save of the image

Rendering the Plot

In order to plot the parameters of each column onto the plot, a number of steps had to be taken in order to reduce the number of variables from five to three.
First, all of the parameters were divided by H. Having reduced the number of parameters to four, the remaining extraneous parameter is simply removed from the equation. Because A generally has the least effect on the column in the HSM equation, this is the parameter removed by default. However, the option to remove any of the four parameters is given underneith the graph.
Having reduced the equation to three parameters, the data is then adjusted so that it can be graphed. Because each of the parameters will have a different significance chemically, both in general and depending on the experiment, each of the data points must be normalized according to weighted value. This weight value can be changed in the "Select Fs Weighting Factors" portion of the website. Each of the three parameters for a particular column are multiplied by its corresponding weight value and then the column is graphed according to these normalized parameters as a point on the graph. Any and all calculations used in the actual rendering of the plot are handled by

About Us

This website was created by Dr. Dwight Stoll with help from Dr. Paul Boswell. Continued maintenece of this site, in addition to the overhaul of the column comparison rendering is handled by Sarah Caldow and Ray Sajulga.
If you have any questions, please contact Dwight Stoll at