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This calculator supports laboratory preparation of research-material stock solutions and analytical aliquots. It calculates concentration and volumetric transfer only.
For laboratory and analytical research only. It does not provide dosing or administration information. Not for human or veterinary use.
Laboratory calculation
- Reference-material mass: the verified mass used to prepare the stock solution.
- Compatible solvent volume: the final liquid volume after preparation.
- Target analytical quantity: the mass required in an aliquot or assay sample.
Stock concentration = reference-material mass ÷ solvent volume. Required aliquot volume = target analytical quantity ÷ stock concentration.
- Stock concentration
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- Required aliquot/sample volume
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Use a calibrated micropipette or validated volumetric-transfer method appropriate to the required range and the laboratory’s standard operating procedure.
Worked laboratory example
5 mg reference material combined with compatible solvent to a final volume of 5 mL produces a 1 mg/mL stock concentration. An analytical quantity of 100 µg would require a 0.1 mL (100 µL) aliquot.
Good laboratory practice
- Confirm material identity, batch number and verified mass against the applicable Certificate of Analysis.
- Select a solvent that is compatible with the material and intended analytical method; do not assume one solvent is suitable for every sequence.
- Use calibrated volumetric equipment and record the actual final volume.
- Label stock solutions and aliquots with material identity, batch, concentration, solvent, preparation date and storage condition.
- Prepare single-use aliquots where appropriate to reduce repeated freeze/thaw exposure.
Frequently asked questions
Does changing solvent volume change the total material mass?
No. It changes the stock concentration, not the total mass initially transferred.
Can this calculation be used for multi-component reference materials?
Only when the verified mass or component ratio is known. Calculate each component from documented composition rather than assuming the combined nominal mass represents every component equally.
What if the calculated aliquot is outside the reliable range of available equipment?
Prepare an appropriate intermediate dilution using a documented laboratory method, then recalculate from the verified dilution factor. Do not report volumes below the validated range of the calibrated pipette.
