Drybench Calc product page
Drybench Calc.
Salt form, hydrate and purity
Formula weights of a salt or hydrate and its parent, the shortfall of weighing the parent mass, and the purity correction.
Molarity and stocks
The mass to weigh for a concentration and volume, or the volume for the mass you actually weighed.
Convert units
This action changes the number and unit together, preserving the physical quantity. The unit menu above continues to assign a unit to the entered number.
Convert units
This action changes the number and unit together, preserving the physical quantity. The unit menu above continues to assign a unit to the entered number.
Compound on the sheet: imatinib mesylate
Answer
- Weigh
- 6.018mg
- Purity 98.0 percent applied.Stock mass with salt form, hydrate and purity
- Concentration
- 10 mM
- Final volume
- 1 mL
- Formula weightas typed
- 589.72 g/mol
- Purity
- 98.0 %
- Solvent
- DMSO
Open in the bench sheetThe bench sheet carries these inputs and offers the other calculators.
Worked example
- Imatinib (C29H31N7O) is 493.62 g/mol; imatinib mesylate (C30H35N7O4S) is 589.72 g/mol, both by CIAAW 2021.
- The parent is 83.7 percent of the mesylate's weight, so weighing the parent's mass for a mesylate stock falls short by 16.3 percent.
- A hydrate is the anhydrous formula plus n × 18.015 g/mol: CaCl2·2H2O is 147.01 g/mol against 110.98 anhydrous. A purity below 100 percent divides the mass to weigh.
Method
- Stock mass with salt form, hydrate and purity. src/lib/dilution/stock.ts 1.0.0Checked against Python's exact rational arithmetic (fractions.Fraction) to nine significant figures on 31 fixtures (6 October 2026).
- Formula weight from the molecular formula. Prohaska T et al. Standard atomic weights of the elements 2021 (IUPAC Technical Report). Pure Appl Chem 2022;94:573-600. doi:10.1515/pac-2019-0603; ciaaw.org, read 6 October 2026.Checked against a CIAAW 2021 sum in Python's decimal module, with the formula from RDKit 2026.03.6, exactly on 58 fixtures (6 October 2026).
Constants
- ciaaw-2021: IUPAC CIAAW 2021 standard atomic weights, conventional values for interval elements
Limits
- For research and education only, and not medical advice: the stock, dilution and buffer calculations here are not for dosing or clinical preparation.
- Formula weights use the IUPAC 2021 conventional atomic weights, so a vendor label may differ in the third decimal; a weight typed from the vial or a certificate of analysis overrides every computed value.
- The serial-dilution planner assumes each tube is made in one step from the tube before it and that the diluent carries no solvent of its own. Every tube, the last included, is made to the same volume with the same transfer, so the last keeps one transfer's volume over. Serial dilution 1.0.0: last point under-diluted by f/(f − 1); any plan printed from 1.0.0 is affected.