Peak concentration/levels definition

One definition of detection limit is the concentration of an element that gives a signal equal to two times the peak-to-peak noise level of the baseline (Figure 21-23). The baseline noise level should be measured for a blank sample.16... 

Quantification of the limits of detection (LOD), or minimum detectable levels (MDL statistically defined in Section 13.4), is an important part of any analysis. They are used to describe the smallest concentration of each element which can be determined, and will vary from element to element, from matrix to matrix, and from day to day. Any element in a sample which has a value below, or similar to, the limits of detection should be excluded from subsequent interpretation. A generally accepted definition of detection limit is the concentration equal to a signal of twice (95% confidence level) or three times (99% confidence) the standard deviation of the signal produced by the background noise at the position of the peak. In practice, detection limits in ICP-MS are usually based on ten runs of a matrix matched blank and a standard. In this case ... 

In the European community, the occupational exposure level is defined as the limit of the time-weighted average of a chemical agent in the air within the breathing zone of a worker in relation to a specified reference period, usually 8 h or a work shift. In addition, to avoid adverse health effects, there is a need to set limits for short-term exposure peaks. In the occupational safety legislation of most countries within the European Community the lists of occupational exposure levels include limits for short-term exposure for many substances, either in the form of definite concentration values or so-called short-term exposure factors. In case of factors, the allowed maximum short-term concentration is calculated by multipHca-tion of the OEL by the short-term exposure factor. Typically, many hazardous substances have factors within the range of 1-4. 

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