multi N/C 2100S (duo, pharma)
Function and design
35
Diluent blank value
If the sample is diluted, the blank value for the diluent is of interest. This value can be
determined separately or entered manually in the software. The software takes the dilu-
ent blank value into account when calculating the concentration of diluted samples.
The diluent blank value can change over time and must therefore be determined again
before beginning a measurement series. Otherwise, the software will use the last value.
The diluent blank value is always indicated in the software normalized to a volume of
1 ml.
Diluent blank value use
The software calculates the actual diluent integral (I
DiBV
) for each measurement based on
the diluent blank value, the sample volume used and the dilution ratio. The software
then subtracts the diluent integral (I
DiBV
) from the experimentally determined raw inte-
gral (I
Raw
).
I
DiBV
= V
DiBV
x (V
Sample
– N
P
/N
D
x V
Sample
)
I
eff
= I
Raw
– I
DiBV
V
DiBV
: Diluent blank value
V
Sample
Sample volume
I
eff
: Effective integral
N
P
: Number of units of the primary sample
N
D
: Number of units of the diluent
I
Raw
: Raw integral
I
DiBV
: Diluent integral
Diluent indication
Proportions of the primary probe: in total proportions (e.g., 10 parts in 100 parts)
This means that 10 ml of the primary sample is filled to a total volume of 100 ml with
dilution water.
A 1:1 dilution ratio equals I
DiBV
= 0.
Calculation of the sample con-
centration
To calculate the sample concentration c, the sample volume and the dilution ratio are
used:
c = m/V
Sample
x N
D
/N
P
The following equation applies for the linear calibration function:
c = (k
1
x I
eff
+ k
0
)/V
Sample
x N
D
/N
P
If the user dilutes a sample and enters the dilution ratio in the software, the software
automatically calculates the concentration of the undiluted primary sample and outputs
it to the analysis report.
3.7.2
Eluate blank value
The eluate blank value is a special blank value for samples from cleaning validation or
eluate preparation. It corresponds to the TOC content of the ultrapure water used which
has been used, e.g., to extract/eluate swabs.
The eluate blank value is a fixed method parameter. The user can activate or deactivate
the eluate blank value in the method. The user can optionally determine the eluate
blank value separately and enter it in the software manually.
The blank value can change over time and must therefore be determined again before
beginning a measurement series. Otherwise, the software uses the last value.
The eluate blank value is always indicated normalized to 1 ml.
