| Index |
Lab Tools: Solutions
| OUTLINE This module calculates how several stock solutions -- for example, enzymes, buffers, salts -- should be mixed together to produce desired concentrations in resulting buffer. Very uniquely to this program, stock solutions can be mixtures themselves. For example, the module can account for components carried in with one of the stocks, when calculating the final reaction mixture. For example, if enzyme contains 250 mM NaCl and desired final concentration of NaCl is 70 mM, the module can automatically adjust volume of 1M NaCl stock to be added at different final enzyme concentrations. Up to 8 components (solutes) can be calculated at the same time. Of those, up to 4 can be multi-component mixtures themselves. Note: to get the answers, the program has to solve up to 4x8 matrix, which equals to over a hundred arithmetic operations. This explains why it may seem so difficult to calculate solution mixtures of even moderate complexity. The resulting data can be printed using built-in printer interface or saved as PDF. See this example: PrintableDilution.pdf A SIMPLE CALCULATION For a simple calculation, one solute (S), its stock concentration (C), concentration desired (f/c) and total volume desired (Sigma volume) are entered. In the output, the program calculates volumes of solute S and water (or solvent) to add. If the stock concentrations are too dilute, the resulting volumes may become negative and will by highlighted red. VIEWING, PRINTING AND SAVING To view the results: values can be pasted raw by raw to the main text box using S, C, f/c or V buttons, or all at once using the Auto button. The ">" button will expand the data for browsing or editing. The data can also be viewed in color via the C button on the left side or via the print preview button. The print matrix check box prompts printing the cross-component matrix for components 4-7. All dilution entries can be saved as a *.dca file and opened later using the Open/Save buttons. CONCENTRATION SERIES AND AUTOMATION It is possible to calculate and print concentration series. One approach would be to select desired cells by double-clicking (this will highlight them yellow) and transforming them by pressing the T button to the left. Parameters for transform are located under the Settings menu. Another approach involves the Auto sample menu. There, one specifies a component to vary, its lowest and highest concentrations, and the scale to use for increments (linear or log). Pressing GO! button will vary concentrations of components 1-8 in the range specified and fill the output text box. The results can be printed or saved as a colored PDF file by printing to PDF.