Nachweisempfindlichkeit

Nachweisempfindlichkeit, often translated as detection sensitivity, denotes the smallest amount of an analyte or the weakest signal that a measurement method can reliably detect under defined conditions. It is a key performance characteristic of analytical instruments, sensors and radiometric devices and complements factors such as accuracy, precision and dynamic range. Detection sensitivity is influenced by instrument noise, background signals, sample matrix complexity, measurement time and environmental conditions.

Two related concepts are the limit of detection (LOD) and the limit of quantification (LOQ). The LOD is typically defined as the lowest concentration that can be distinguished from the blank with a specified confidence, often corresponding to a signal-to-noise ratio near 3:1. The LOQ is the lowest concentration that can be quantified with acceptable precision, commonly at S/N around 10:1. Both are estimated from calibration data or repeated blank measurements.

Measurement approaches vary across domains: spectroscopy, chromatography, electrochemical sensing and radiometry each have characteristic sensitivity determinants such as detector efficiency, integration time, electrode surface and background interference. The sample matrix and preparation can enhance or degrade sensitivity, while noise reduction techniques and signal processing can improve detectability.

Trade-offs exist: increasing sensitivity can shrink the dynamic range, increase measurement time, or raise vulnerability to interferences. Nachweisempfindlichkeit is crucial in environmental monitoring, clinical diagnostics, food safety and other areas where trace-level detection is necessary, but it must be balanced with reliability, cost and practicality.