74
2 Analytical Properties
Lowering costs usually entails sacrificing on some other analytical property
(whether capital, basic or accessory). The contradictory relationships that
emerge are exposed in the next section.
Overhead costs arise from laboratory set-up and maintenance, the purchase
and maintenance of equipment and the salaries of the staff (managers,
secretaries, cleaning crew). As a rule, they are considered fixed costs even though
they can certainly vary to some extent.
Specific costs are those to be paid by the laboratory's clients, i. e. by those who
demand the information delivered. The difference between what the client
actually pays and specific costs can be used as a criterion to establish the quality
of an analytical process. Specific costs can also be fixed or variable. In any case,
they should be balanced in relation to the number of analyses required, the
throughput and the desired level of accuracy (uncertainty) in the results. This
entails individual optimization in each case. Automation raises fixed costs (those
of equipment) but decreases variable costs (it reduces man-hours); this is only
acceptable when a large number of samples is to be processed or high expeditiousness is demanded.
Box 2.13
Choosing an analytical technique on the basis of two complementary analytical
properties: cost-effectiveness and throughput
The following example is intended to illustrate the influence of two accessory analytical
properties (expeditiousness and cost-effectiveness) on the choice of the analytical technique
to be used in an analytical process, which will obviously affect its performance.
The determination of inorganic nitrogen in a fertilizer can be carried out by using a large
variety of analytical techniques that use a wide range of equipment from a modest burette to
ig 10
u
/
euuon actIVation
/
/
/
/
/
/
,
/
/
lu.o
neuuon
L..- d_ isl _ ila_ llo_ n _--,r se _le_ Cli _ ve_el _ eC_ tlod _ e --r __ aU_IDa _na _"_ Ar ...,acllvatlon
10
100
1000
NUMBER OF ANALYSES PER DAY
2 Analytical Properties
Lowering costs usually entails sacrificing on some other analytical property
(whether capital, basic or accessory). The contradictory relationships that
emerge are exposed in the next section.
Overhead costs arise from laboratory set-up and maintenance, the purchase
and maintenance of equipment and the salaries of the staff (managers,
secretaries, cleaning crew). As a rule, they are considered fixed costs even though
they can certainly vary to some extent.
Specific costs are those to be paid by the laboratory's clients, i. e. by those who
demand the information delivered. The difference between what the client
actually pays and specific costs can be used as a criterion to establish the quality
of an analytical process. Specific costs can also be fixed or variable. In any case,
they should be balanced in relation to the number of analyses required, the
throughput and the desired level of accuracy (uncertainty) in the results. This
entails individual optimization in each case. Automation raises fixed costs (those
of equipment) but decreases variable costs (it reduces man-hours); this is only
acceptable when a large number of samples is to be processed or high expeditiousness is demanded.
Box 2.13
Choosing an analytical technique on the basis of two complementary analytical
properties: cost-effectiveness and throughput
The following example is intended to illustrate the influence of two accessory analytical
properties (expeditiousness and cost-effectiveness) on the choice of the analytical technique
to be used in an analytical process, which will obviously affect its performance.
The determination of inorganic nitrogen in a fertilizer can be carried out by using a large
variety of analytical techniques that use a wide range of equipment from a modest burette to
ig 10
u
/
euuon actIVation
/
/
/
/
/
/
,
/
/
lu.o
neuuon
L..- d_ isl _ ila_ llo_ n _--,r se _le_ Cli _ ve_el _ eC_ tlod _ e --r __ aU_IDa _na _"_ Ar ...,acllvatlon
10
100
1000
NUMBER OF ANALYSES PER DAY