5.2 The Binary Response
205
Box 5.3
Below are some examples of possible binary responses (Fig. 5.2) to a demand of qualitative
chemical information.
First-level information demands
• Is this beef of pork?
• Is there any cadmium in the paint coating of this toy?
• Are there any aflatoxins in this imported dried fruit batch?
• Has this meat product been adulterated with vegetable protein?
Second-level information demands
• Is this water contaminated with hydrocarbons as per the threshold globa l index set by the
European Union?
• Is the aluminium concentration in this hemodialysis fluid acceptable?
• Is this soft drink fit for consumption as per the legally established limit for the concentration of the preservative it contains?
Third -level information demands
• Is this water, wh ich may contain various mercury species (organic, organometallic), fit for
drinking even if its total mercury content is near the tolerated limit?
• Is the price of this pharmaceutical preparation, where one enantiomer is the active principle and the other is therapeutically useless, acceptable?
Fourth-level information demands
• In what part of the surface of this object is the composition such that breakage or
deterioration is most likely?
• At what point in this ore slag stack is the proportion of gold highest?
• At what time of year is the overa ll pollution index (e.g. chemical oxygen demand) highest
at this point of the river?
Some analytical problems require expanding the most simple binary response with
temporal (e. g. answering the question «when?" for dynamic objects from which the
samples are withdrawn) or spatial discrimination (i. e. answering the question
«where?" for heterogeneous objects such as those involved in surface analysis).
Consequently, even in its most simple possible form, the YES/NO binary
response can differ chemically, spatially and temporally from case to case.
I 5.2.2 Quantitative Connotations of the Binary Response
As can be seen from Fig. 5.1, qualitative information invariably possesses some
quantitative connotations; essentially, to obtain the former one compares data
(signals) produced in response to given concentrations or amounts of analyte. To
this end, one must use the references schematically depicted in Fig. 5.3, placed on
an imaginary concentration scale. Such references are as follows:
(a) The limit of detection, ClOD' which is the concentration yielding a signal
XWD that can be statistically discriminated from a blank signal, is, and
205
Box 5.3
Below are some examples of possible binary responses (Fig. 5.2) to a demand of qualitative
chemical information.
First-level information demands
• Is this beef of pork?
• Is there any cadmium in the paint coating of this toy?
• Are there any aflatoxins in this imported dried fruit batch?
• Has this meat product been adulterated with vegetable protein?
Second-level information demands
• Is this water contaminated with hydrocarbons as per the threshold globa l index set by the
European Union?
• Is the aluminium concentration in this hemodialysis fluid acceptable?
• Is this soft drink fit for consumption as per the legally established limit for the concentration of the preservative it contains?
Third -level information demands
• Is this water, wh ich may contain various mercury species (organic, organometallic), fit for
drinking even if its total mercury content is near the tolerated limit?
• Is the price of this pharmaceutical preparation, where one enantiomer is the active principle and the other is therapeutically useless, acceptable?
Fourth-level information demands
• In what part of the surface of this object is the composition such that breakage or
deterioration is most likely?
• At what point in this ore slag stack is the proportion of gold highest?
• At what time of year is the overa ll pollution index (e.g. chemical oxygen demand) highest
at this point of the river?
Some analytical problems require expanding the most simple binary response with
temporal (e. g. answering the question «when?" for dynamic objects from which the
samples are withdrawn) or spatial discrimination (i. e. answering the question
«where?" for heterogeneous objects such as those involved in surface analysis).
Consequently, even in its most simple possible form, the YES/NO binary
response can differ chemically, spatially and temporally from case to case.
I 5.2.2 Quantitative Connotations of the Binary Response
As can be seen from Fig. 5.1, qualitative information invariably possesses some
quantitative connotations; essentially, to obtain the former one compares data
(signals) produced in response to given concentrations or amounts of analyte. To
this end, one must use the references schematically depicted in Fig. 5.3, placed on
an imaginary concentration scale. Such references are as follows:
(a) The limit of detection, ClOD' which is the concentration yielding a signal
XWD that can be statistically discriminated from a blank signal, is, and