Sterility Testing
Definition
Incubation of a sample in growth media to confirm no viable microorganism is present. Sterility is a property of a validated process and its container and is independent of chemical purity: a very pure material can be non-sterile and often is.
What this means for research sourcing
Purity and identity verification are central to research reproducibility. Every Volta compound ships with >99% HPLC-verified purity and a certificate of analysis.
Related Terms in Quality
Sterility
The absence of viable microorganisms in a preparation. It is conferred by a process and preserved by a closure, so it is lost the moment either is compromised and nothing about the appearance of a vial reports that.
Assay
Any procedure that measures whether something is present, how much of it there is, or how active it is. Analytical assays report composition; functional assays report activity, and a material can pass one and fail the other.
Quality Control (QC)
The testing a batch passes through before release, typically identity by mass spectrometry, purity by HPLC, content and, where relevant, water, sterility and endotoxin. QC is the set of tests; the certificate is the report of their results.
Degradation Product
A compound formed as a peptide breaks down, through oxidation, deamidation, hydrolysis or aggregation. Certificates report these as impurity peaks, and their pattern says more about how a batch was handled than the headline purity figure does.
Reference Standard
A well-characterised sample run alongside an unknown so that retention time and response can be compared against something known. Without one, a chromatogram shows separation but supports no identification.
Batch Number
The identifier tying a quantity of material to the records of its manufacture and testing. It is the only thing linking a vial in hand to a certificate on a screen, which is why a certificate whose batch number does not appear on the label proves nothing about that vial.
Third-Party Testing
Analysis by a laboratory with no commercial interest in the result, as against in-house testing by the manufacturer or seller. The independence is the whole value, and it is only real if the laboratory is named and its report is reproducible.
X-Ray Crystallography
Determination of a molecule's three-dimensional atomic structure from the diffraction pattern of a crystal of it. It is a structural method rather than a release test, and it is how most receptor and ligand geometry in the literature was established.
