The exact enantiomer is part of the product identity
S(-)-3-hydroxy-gamma-butyrolactone, S- and R-3-hydroxytetrahydrofuran, D-malic acid, D-tartaric acid and the D- and L-forms of diethyl tartrate occupy different positions in pharmaceutical and asymmetric-synthesis routes. Confirm structure, absolute configuration, salt or ester form and the route step before requesting a sample.
A catalogue name may not show all route-critical details. Optical rotation and enantiomeric excess should be connected to a defined method, solvent, concentration and temperature.
Impurities can carry forward
Agree assay, ee or chiral purity, water, related substances, residual solvents, color and selected process impurities. For liquids, density and refractive index may help confirm identity. For crystals, melting range and particle behavior may affect handling. The analytical method should be suitable for the buyer's downstream impurity strategy.
Qualification must represent commercial manufacture
Ask about synthetic route, starting-material control, batch size, campaign planning, change notification, packaging, moisture protection and retest period. A development sample should represent the proposed commercial route whenever possible. The referenced S-HGBL supplier lists 25, 50 and 200 kg packages, illustrating why qualification and scale planning should be discussed together.