Detection limits must reflect the method, matrix, and decision
A detection limit is not simply the smallest peak that can be seen in one pattern. For solid-mixture analysis, the result depends on instrument noise, phase response, sample preparation, matrix behavior, concentration, and the probability of reliable detection across replicate measurements.
What the resource covers
- Visual evaluation, signal-to-noise, and calibration-based approaches described in analytical validation guidance.
- How Poisson and Gaussian behavior can be used to characterize XRPD background and peak-count variation.
- The use of validation mixtures and replicate measurements to demonstrate a practical detection limit for a solid-phase limit test.
Key scientific takeaways
Visibility alone is not validation
A peak observed once does not establish a reliable detection limit. Repeatability and the probability of detection must be demonstrated.
The matrix controls real performance
Particle size, preferred orientation, absorption, mixing, and phase response can make a matrix-specific detection limit different from an instrument-only estimate.
Confirm the proposed limit
A defensible limit test uses samples near the proposed threshold and documents that the target phase is detected consistently under the intended method conditions.
Document details
| Document type | Whitepaper |
|---|---|
| Title | Establishment and Calculation of Detection Limits for Solid Mixture Analysis |
| Author | G. Patrick Stahly, Ph.D. |
| Publication date | March 2019 |
Download this Whitepaper
Complete the short request form and the document link will be sent by email.