Analytical Method
Definition
The written procedure a laboratory follows to produce a result: sample preparation, instrument conditions, how the signal is turned into a number and what counts as a valid run. Two laboratories reporting different purities for one lot are usually running different methods rather than disagreeing.
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
Acceptance Criterion
The limit a result is judged against, fixed before the sample is run. A purity specification of not less than 99% is an acceptance criterion; a result of 98.7% fails it whatever the laboratory thinks of the material.
Accuracy
How close a measured value sits to the true one. It is established against a reference standard, and it is independent of precision: a method can repeat the same wrong answer all day.
Precision
How close repeated measurements of the same sample fall to each other, reported as a relative standard deviation. Repeatability is precision within one run, intermediate precision across days and analysts in one laboratory.
Reproducibility
Agreement between results for the same material measured in different laboratories. It is the widest form of precision and the one that matters when a buyer sends a vial for independent testing.
Calibration
Relating an instrument's signal to known quantities of a reference standard, so a peak area can be read as a concentration. An uncalibrated instrument still produces numbers; they just do not mean anything outside that run.
Method Validation
The documented exercise proving a method does what it claims: specificity, linearity, accuracy, precision, range, and the limits at which it stops working. Validation is done once for the method, not once per sample.
Method Verification
Demonstrating that an already-validated method performs as expected in the laboratory now using it. A compendial method arrives validated; a laboratory still has to show its own instruments and analysts reproduce it.
System Suitability
Checks run immediately before samples to prove the instrument is fit to measure anything that day: peak shape, resolution between critical pairs, and repeatability of replicate injections. A failed system suitability invalidates the run rather than the material.