Version 1.3.4
The graphics functionality lost when using the Big Sur or higher operating system has been restored
Version 1.3.3
Minor update with a new support website and privacy statement.
Version 1.3.2
Minor update.
Version 1.3.1
The program has been updated to a 64 bit application
Version 1.3.0
The program can now read csv files. Select "Open csv file" in the File menu to open csv files.
In this version the ability to remove individual data rows from the input data has been added.
Version 1.1.0
The application has been sandboxed.Description
This program fits data to the equations:-Alkaline sigmoid
kobs = k/(1+[H]/Ka)
Acid sigmoid
kobs = k/(1+Ka/[H]
When "Fit" is selected a linear reciprocal plot is used to make the initial estimates of kobs and the pKa. These values of kobs and pKa are then used as the initial estimates to fit the experimental data using an iterative, non linear least-squares regression program.
When "Fit with estimates" is selected you must input the initial estimates of kobs and the pKa. The experimental data is then fitted using an iterative, non linear least-squares regression program.
Results can be printed, saved as a text document or copied and pasted into other applications such as Word.
Specific instructions:-
FIRST INPUT DATA OR OPEN SAVED DATA
Buttons will be enabled as you need them.
Test data
Alkaline sigmoid
pH----kobs
5-----0.1
7-------7
8-------45
9-------86
11------96
Acid sigmoid
pH----kobs
3----100
5----91
6----50
7----9
9----0.1
Enter data into the boxes "pH" and "kobs"
Press button "Add Data"
Enter data into the boxes "pH" and "kobs"
Select button "Add Data"
Repeat until all data is entered.
A minimum of 3 different data pairs are required but preferably more points should be added.
Then you can save the data as a text file by selecting the "Save Data" button.
You can then reload the data at any time by selecting "Open Saved Data".
Selecting the "output data" button outputs data to the output window.
TO ANALYSE DATA
Select the required fit. In most cases the option "Fit" will be suitable. Occasionally the initial linear fit will not give suitable initial estimates. In this case you should enter your own estimates and select the "Fit with estimates" option which will be available after you have used the "fit" option.
Answers for test data
Alkaline sigmoid
pKa=8.033712---SE=0.0525495
k=94.8389------SE=3.242214
Acid sigmoid
pKA=5.997642---SE=0.002291
k=100.1306-----SE=0.1481339
After selecting the required fit the analyzed data, fitted data and the fitted parameters will be outputted to the Output window. This output can be selected, printed or copied and pasted into other applications such as word. These options will be found under the File and Edit menus.
Then select the type of scale you require.
Select "Change scales etc" and carefully enter the changes you require.
After changing the graph scales, press redraw to implement the changes.
To give the graph a title and label the axes, select "Graph labels" and make the appropriate changes.
AFTER CHANGING THE GRAPH SCALES, AXES OR LABELS PRESS "REDRAW" TO IMPLEMENT THE CHANGES.
Select "Print graph" to output the graph to your printer.
Select "Copy graph" to copy the graph to the clipboard. You may then paste it into other applications such as Word.
If you want to calculate theoretical data you can select " Set parameters for calculating kobs values" enter values, then select "Calculate kobs values for alkaline sigmoid" or "Calculate kobs values for acid sigmoid" to output the data to the output window.
