detectables

Detectables are the objects, signals, or substances that can be observed or measured by a detection system. Whether something is detectable depends on the target’s properties, the environment, and the capabilities and limitations of the detector, including sensitivity, dynamic range, resolution, and noise levels. In practice, detectability is a function of signal strength relative to background and interference.

In chemistry, a compound or marker is detectable if an assay or instrument such as mass spectrometry, chromatography, or fluorescence yields a measurable signal above background. In physics, particles, decays, or interactions are detectable if detectors register events with sufficient confidence. In medicine and environmental monitoring, biomarkers, contaminants, or pollutants are detectable when assays or sensors produce signals above the limit of detection.

Key concepts related to detectables include the limit of detection (LOD), limit of quantification (LOQ), sensor sensitivity, specificity, and detection efficiency. The probability of detection depends on signal-to-noise ratio, attenuation, and measurement duration. Equally important is the rate of false positives and false negatives, which influence the reported detectability.

Limitations and challenges include weak signals, high background, interference, and instrumental drift. Some targets may be inherently undetectable with current technology or require indirect methods or invasive sampling. Detectability can also vary with context, such as environmental conditions, sample matrix, or observer expertise.

Applications and design considerations focus on selecting appropriate detectors, calibrating instruments, and validating performance. Clear reporting of LOD/LOQ, calibration methods, and uncertainty helps ensure reliable interpretation of detectable signals.