Mass concentration and molar concentration for peptides
Understand the difference between mass per volume and amount of substance per volume, with a worked conversion and its assumptions.
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Daltons and kilodaltons explained
Read Da and kDa as molecular mass units, convert between them and avoid confusing molecular size with the amount in a vial.
Read the article →Nanomolar, micromolar and millimolar notation
Convert nM, µM and mM accurately and catch prefix, case and transcription errors when reading laboratory concentrations.
Read the article →Percentage units on laboratory documents
Identify the numerator and denominator behind percentages, and distinguish percentage points from relative percentage changes.
Read the article →Parts per million and parts per billion in impurity reports
Decode ppm and ppb, preserve their composition basis and avoid treating mass fractions as liquid concentrations without density information.
Read the article →Molar ratios in multicomponent materials
Distinguish a ratio of amounts in moles from a mass ratio, a fraction of the total and evidence of chemical association.
Read the article →Significant figures in peptide specifications
Read the precision implied by a written number without mistaking extra digits for a smaller measurement uncertainty.
Read the article →Rounding analytical results without changing their meaning
Apply a stated rounding convention, avoid repeated rounding and preserve the information needed for comparisons near a specification limit.
Read the article →Dimensional analysis for checking peptide calculations
Use units to detect missing factors and incorrect algebra, while recognising that matching dimensions does not prove a calculation's scientific basis.
Read the article →When a unit conversion is impossible without more information
Recognise when a requested conversion needs molecular identity, composition, density or a measurement relationship that the source has not supplied.
Read the article →How peptide ligands interact with receptors
Read a peptide–receptor interaction claim by separating molecular recognition, binding evidence and the response measured in the experiment.
Read the article →Agonists, antagonists and partial agonists
Understand functional receptor labels, why partial agonism depends on the experimental system, and how to avoid turning the labels into a ranking.
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