Preparation
Preparation: 5 articles from Peptides Info. Handling, storage and laboratory reference.
Weighing and Handling Hygroscopic Solids: Moisture, Static and the Case for Not Weighing
Lyophilised peptide gains water while it sits on the pan, carries charge, and is weighed in quantities where balance error is proportionally large. The control for each, and the route that removes the weighing entirely.
Filtration and Particulate Control: What a Membrane Removes, Including Peptide
Filtration removes particulate and aggregate above the pore rating, and removes peptide by binding it to the membrane. Membrane materials compared, with a procedure for re-measuring what survives the pass.
Stock Solutions and Dilution Series: Concentration Arithmetic
One weighing carried into a whole concentration range by volumetric transfer. Molar and mass concentration, serial versus direct dilution, solvent carry-over, and a worked series.
Solvent Selection and Dissolution: Choosing a Solvent and Getting Peptide Into Solution
Solvent choice is set by the sequence, not by the assay. Charge assessment, a solvent selection table, the dissolve-then-dilute order, and what to record against a batch.
Net Peptide Content and Gross Weight
The mass printed on a vial is total solid, not peptide. This is what makes up the difference, how the peptide fraction is determined, and how to carry it through a concentration calculation.