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4.5.2.2 Formulae for the Preparation of Solutions
A selection of special calculation formulae is available for the Prepare Solutions mode.
The appropriate calculation formula is selected on the «Formula Selection» submenu (Fig. 68).
Fig. 68
A selection of 3 different calculation formulae is available:
W*(100-Fa-Fb)*Fc/Fd - W*(100-Fb)/(100*Fe) +Ff
W*(100-Fa-Fb)*(Fd/Fg) - W*(100-Fb)/(100*Fg) +Ff
W*(100-Fa-Fb)*Fc/(100*Fd)
Meaning of the individual factors:
W: Weight of the sample in g
Fa: Soluble foreign-matters portion in %
Fb: insoluble foreign-matter portion in %
Fc: Conversion factor for it unit
g/l = 10
mg/l und ppm = 10000
g/100 ml = 1
% = 1
Fd: Target concentration of the solution to be prepared in g/l, mg/l (ppm), g/100 ml, or %
Fe: Specific weight of the weighed-in sample in g/cm³
Ff: Volume correction in ml. this volume correction is the required surplus dosage for compensating the volume
contraction and the specific-weight difference between the sample weight and the solvent (please observe the note
on volume correction)
Fg: Specific weight of the solvent used in g/cm³
Note on volume correction:
The user has to decide on a case-by-case basis whether a volume correction is necessary and according to
which procedure this correction is to be performed. As a rule, this volume correction may be omitted in the case
of solutions with very low percentages of diluted substance.
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