| Raman spectroscopy | Can identify many drugs by comparing a sample spectrum with a reference library. Mixtures, fluorescence, packaging, and low-concentration ingredients can reduce confidence. | Best suited to bulk or relatively concentrated samples; generally not a reliable method for trace-residue detection. | About 10–60 seconds for a measurement; sample handling and repeat scans can add time. | Useful for rapid, non-destructive screening of powders and some packaged materials. Confirm ambiguous results and mixtures with another method. |
| Portable FTIR spectroscopy | Provides a molecular fingerprint that can support identification of many bulk substances. Performance is affected by mixtures and sample contact or preparation. | Primarily suited to bulk samples; typically not intended to detect tiny trace residues on surfaces. | About 30 seconds–2 minutes per sample, depending on preparation and repeat analysis. | Useful for on-site analysis of powders, solids, and some liquids. A clean, representative sample improves results. |
| Ion mobility spectrometry (IMS) | Provides rapid screening for substances included in the instrument’s method library. A screening alarm may require confirmatory testing. | Can detect trace residues collected on a swab; sensitivity is often in the nanogram range, but varies substantially by substance and sampling method. | Often seconds to under a minute after sampling; swabbing and instrument readiness add time. | Well suited to trace screening of surfaces, hands, or objects. Sampling quality and potential interferents affect results. |
| Colorimetric field test | Produces a presumptive color reaction for selected substance groups; it usually cannot uniquely identify a compound or reliably distinguish mixtures. | Designed for a visible sample portion, not dependable trace-residue measurement. No single detection limit applies across test kits and substances. | About 1–5 minutes, including the reaction and visual interpretation. | Low-cost, simple preliminary screening. Results should not be treated as definitive identification, particularly when consequences are significant. |
| Portable mass spectrometry | Can provide highly specific chemical identification when the method, reference data, and sample introduction are suitable; performance remains analyte- and method-dependent. | Ranges from trace-level to larger sample quantities depending on the instrument and sampling approach; request validated, substance-specific limits. | Typically a few minutes per sample; preparation, tuning, and confirmatory runs may extend the process. | Useful when stronger chemical identification is needed in the field. Often requires more training, maintenance, and sample preparation than simple screening tools. |