Kaiser-Ehrlich limits

A detailed derivation can be found in Bauer et al. [1991b]. The limit of detection according to Eq. (6.116a) corresponds to Kaiser s so-called 3a criterion see Sect. 7.5., Lorber and Kowalski [1988] as well as Faber and Kowalski [1997b] take into account errors of the first and second kind. The multivariate detection limits are estimated then in analogy to the univariate limits being twice the 3a-limit (with ua = up) see Sect. 7.5 and Ehrlich and Danzer [2006]). 

For this reason, a number of analysts uses a further limit quantity, namely the limit of quantification, xLq, (limit of determination), from which on the analyte can be determined quantitatively with a certain given precision (Kaiser [1965, 1966] Long and Winefordner [1983] Currie [1992, 1995, 1997] IUPAC [1995] Ehrlich and Danzer [2006]). This limit is not a general one like the critical value and the detection limit which are defined on an objective basis. In contrast, the limit of quantification is a subjective measure depending on the precision, expressed by the reciprocal uncertainty xLq/AxLq = k, which is needed and set in advance. The limit of quantification can be estimated from blank measurements according to... 

The situation with detection limit has been discussed in Sect. 7.5. According to Kaiser and Specker [1956]), Kaiser [1965, 1966], Long and Wineford-ner [1983], Currie [1992, 1995, 1997], and Ehrlich and Danzer [2006] etc., the following decisions and reports are recommended ... 

Historically, the simple ka criteria used in Figure 2 are based on numerous simplifications. They are usually based on the standard deviation a of blank value measurements The limit of decision is defined with A = 3. the limit of detection with A = 6, and as one possibility, the limit of quantitation with k= 10 [16). (The k values take into consideration the probability ot of erroneous statistical and, therefore, erroneous analytical decisions. Thus, by fixing k or a, the purpose of the particular trace-analytical procedure can be taken into account.) The basic considerations in such definitions of method limits extend back to H. Kaiser (I4J and G. Ehrlich [17], Kaiser also tried to define characteristic quantities of methods for multicomponent analysis. For reasons of space, simultaneous multicomponent analysis cannot be discussed here [ 18]. [ 19]. The previous discussion reveals how delicate results of trace analyses are in general. To achieve a re.sponsible discussion in public it should be at least reported together with... 

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See also in sourсe #XX -- [ ]

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