Chain of Custody
Definition
The documented record of who held a sample, when, and in what condition, from collection to analysis. Without it a result describes a sample whose history cannot be shown, which matters most when the result is disputed.
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
Audit Trail
The instrument's own tamper-evident log of acquisitions, reprocessing and deletions, with the user and timestamp attached. It is what distinguishes a reported result from the only result obtained.
Decision Rule
The stated convention for how measurement uncertainty is taken into account when calling a result a pass or a fail. Simple acceptance ignores it; a guarded rule requires the result to clear the limit by a margin.
Guard Band
The margin a decision rule holds back from a specification limit to absorb measurement uncertainty. It makes a false pass less likely at the cost of failing material that may in fact conform.
Standard Operating Procedure (SOP)
A controlled document setting out how a task is performed, version-numbered and approved. Analytical results are defensible because an SOP existed and was followed, not because the analyst remembered the steps.
ISO/IEC 17025
The international standard for the competence of testing and calibration laboratories. Accreditation to it is granted by a named body for a defined scope, so a laboratory can be accredited for one test and not another.
Accreditation
Formal recognition by an authorised body that a laboratory is competent for specified activities, with a published scope. It is awarded against a standard and is distinct from certification of a management system, which says nothing about technical competence.
Testing Laboratory
The facility that performed the analysis, named on the certificate. Independence matters to what the certificate is worth: a result from a laboratory with no commercial interest in the material carries weight a supplier's internal figure does not.
Reagent Blank
Everything in the analysis except the sample, carried through the whole procedure. It shows what the solvents, glassware and column contribute, so that signal is not read as something in the material.