Category B Method
Definition
An analytical method with intermediate discriminating power, measuring a characteristic but less structurally specific property. Includes UV-Vis spectroscopy, TLC, GC without MS, HPLC without MS, and capillary electrophoresis. Sufficient as the orthogonal second method in a SWGDRUG-compliant identification when combined with a Category A result.
- Standard
- SWGDRUG identification guidelines
- Power
- Intermediate discriminating power
- Examples
- UV-Vis, TLC, GC without MS, HPLC without MS, capillary electrophoresis
- Role
- Valid orthogonal second method alongside one Category A result
Common questions
Why can't two Category B methods substitute for one Category A method?+
SWGDRUG requires the combination to include at least one method with structurally specific discriminating power, and stacking multiple Category B methods still leaves gaps that closely related compounds could pass through undetected, so at least one Category A result is mandatory.
What is the practical advantage of using Category B methods in a workflow?+
They are typically faster and cheaper for screening large numbers of samples, letting a lab triage and narrow down likely substances before committing the more expensive Category A instrumentation to confirm identification.
Related terms
- Category a Method
- An analytical method that provides the highest level of discriminating power in drug identification, generating structural or molecular fingerprint information. Category A...
- ENFSI Drugs Working Group (DWG)
- European Network of Forensic Science Institutes Drugs Working Group. Publishes best-practice manuals for drug analysis aligned with SWGDRUG tiering principles, operates an...
- Internal Standard (IS)
- A compound chemically near-identical to the analyte, often a deuterated isotopologue (d3-morphine, d5-EDDP, d5-alprazolam, pyrene-d10), spiked into every sample at a known...
- ISO/IEC 17025:2017
- The international standard specifying general requirements for the competence of testing and calibration laboratories. Covers management (document control, non-conforming work, audits) and...
- Measurement Uncertainty (MU)
- A quantified parameter associated with a result that characterises the dispersion of values reasonably attributable to the measurand. Estimated by the GUM...
- Multiple Reaction Monitoring (MRM)
- An LC-MS/MS acquisition mode in which the first quadrupole (Q1) selects a precursor ion at a specific m/z, the second (Q2) fragments...
- NDPS Small Quantity / Commercial Quantity
- Quantity thresholds defined in the schedules to India's NDPS Act 1985 that determine the severity of criminal charge and applicable mandatory minimum...
- Orthogonality (Analytical)
- The requirement that two methods used in a drug identification measure genuinely different physical or chemical properties. Orthogonality ensures that the probability...
- SWGDRUG
- Scientific Working Group for the Analysis of Seized Drugs, established in 1997 by the US DEA and the Office of National Drug...