what does detection limit mean
Probably much to the chagrin of practitioners, the official definition of limit of detection is not really simple: Taking the detection decision at the critical level (LC) leads to a risk a of false detects. Given this critical level, the limit of detection (LD) is construed as the level that will lead to false non-detects with probability b. Common values for a and b are 1% and 5%. The proper values are of course problem-dependent. This definition may lead to surprises.