Metrohm 746 VA Trace Analyzer - Manual (Page 215)

5.4 Storages
746 VA Trace Analyzer / 747 VA Stand
5-64
Parameter Range; Default value / Meaning
• Diluted sample, entry as volume or weight
The volume fraction
V.fraction entered in the SMPL instruction
is used as addition volume for the SMPL instructions irrespective
of
S0 . To obtain the substance content in g/L or g/g for the origi-
nal sample size S0 , the calculated mass concentration ρ
s
( Mass.
conc. , see section 5.5.2) is multiplied by the factor V.total/S0
(see section 5.6.4).
The following is an overview of the various possibilities for the entry of
S0 and the parameters of the SMPL instructions:
S0 S2 V.fraction V.total Vol. for SMPL
instruction
Formula for
final result
Result
unit
L – – – S0 MC: g/L
g d – – S0/S2 MC:/
(S2*1000)
g/g
L – V.fraction V.total V.fraction MC:*
(V.total/S0)
g/L
g – V.fraction V.total V.fraction MC:*
(V.total/S0)
g/g
The following should be noted in connection with the sample quantity
S0 :
• The terms "undiluted sample" and "diluted sample" in the pre-
ceding section refer only to dilutions during the sample prepara-
tion which have not been defined on the "OP.SEQUENCE" or
"SEGMENT" page.
• Dilutions initiated during the program by DOS or transfer instruc-
tions (e.g. addition of auxiliary solutions or pipetting operations
on the Autosampler) are automatically taken into consideration in
the volume bookkeeping (see section 6.9.2). Irrespective of these
dilutions, the calculated mass concentration
ρ
s
of the investigated
substance always refers to the addition volume defined for the
SMPL instruction (that is, depending on the entry, to
S0 ,
S0/(S2*1000) or V.fraction ).
• The effective mass concentration ρ
eff,s
of the investigated sub-
stance in the measuring vessel, referred to the total solution vol-
ume V
eff
which it contains at the start of the first measurement, is
reported only in the graphical representation of the calibration
curve.
• The amount of the original addition volume of the SMPL instruc-
tion which is actually present in the measuring vessel at the start
of the measurement is shown in the parameter
V0.sample on the
"RESULTS" dialog page (see section 5.5.2). This page also
shows the
Mass of the investigated substance found in the
measuring vessel as well as its mass concentration Mass conc. .
The following relation holds:
Mass conc. = Mass / V0.sample