Metrohm 746 VA Trace Analyzer - Manual (Page 307)

5.6 Method Specifications
746 VA Trace Analyzer / 747 VA Stand
5-156
Parameter Range; Default value / Meaning
Ref.subst. 8 characters;
Name of reference substance
Here the name of the substance used as the reference substance
(internal standard) must be specified.
Temperature 0.0...99.9 °C; 25.0 °C
Measurement temperature
Measurement temperature for calibration and measurement.
Owing to the large temperature dependence of the measured values
(
≥ 2%/°C), it is advisable to work with the 6.1418.220 thermostatted
measuring vessel and to enter the set temperature here.
Range min 0.001...999.99 ng...kg/L;
Lower limit of working range
Here, a lower limit can be optionally defined for the working range in
the evaluation with an internal standard. If a mass concentration
Mass
conc. less than the value entered here is found for the substance, an
error message is put out and the remark conc. out of range dis-
played on the "RESULTS" page.
The lower limit of the working range (in terms of the ratio of the effec-
tive mass concentrations
ρ
eff,a
/ ρ
eff,r
) is marked by a vertical line in the
display and on the plot of the calibration curve.
Range max 0.001...999.99 ng...kg/L;
Upper limit of working range
Here, an upper limit can be optionally defined for the working range in
the evaluation with an internal standard. If a mass concentration
Mass
conc. greater than the value entered here is found for the substance,
an error message is put out and the remark conc. out of range
displayed on the "RESULTS" page.
The upper limit of the working range (in terms of the ratio of the
effective mass concentrations
ρ
eff,a
/ ρ
eff,r
) is marked by a vertical line
in the display and on the plot of the calibration curve.
M.conc./cm 0.001...999.99 ng...kg/L;
Axis scaling for plot of calibration curve
The dimensionless ratio of the effective mass concentrations
ρ
eff,a
/ ρ
eff,r
is plotted on the x axis of the calibration curve. As a meas-
ure for the scaling of the x axis, the mass concentration ρ
a
can be
entered here in g/L per cm. To obtain the actual scale of ρ
eff,a
/ ρ
eff,r
,
ρ
a
must thus be divided by ρ
r
and also any dilution taken into account.
In the absence of an entry, the entire curve is plotted within 10 cm.
M.conc.begin auto, zero; auto
Begin of x axis for plot of calibration curve
Selection of the begin of the x axis (mass concentration) for the plot of
the calibration curve:
auto Automatic selection of the begin
zero Begin fixed to zero on x axis