Thermo Scientific Multidrop Combi nL, User Manual

Page: 63 / 106

Routine Operation
Instrument options
Thermo Fisher Scientific Thermo Scientific Multidrop Combi nL User Manual 63
ACCURACY CALCULATION:
Convert the obtained mass to volume (nl) and calculate the accuracy as
follows:
ACCURACY% = 100*Measured volume-Set volume/Set volume
l
Measured volume (in nanoliters) = 1000000*Dispensed liquid mass
(in grams)/Density of the liquid (g/cm
3
)
l
Set volume (in nanoliters) = Expected total volume in the dispensed
strip at the selected volume setting and calibration (
Main
menu).
Note
Calibration curves are calculated from gravimetric results and
volume calculations are always carried out by using density correction,
so real volumes are obtained. The difference between liquid mass and
volume in water is around 0.3% at normal room temperatures and may
be omitted in the accuracy check; but with liquids having a different
density to water, the mass conversion to real volumes should also be
carried out in the accuracy check step.
s
Example:
Accuracy check with water at 200 nl volume set.
1. Measured liquid mass = 0.1815 g
2. Conversion to volume (nanoliters): 1000000*0.1815/0.9969
(water density at 22
°
C) = 182064 nl
3. ACCURACY% = 100*182064 nl-179200 (Expected
volume)/179200 = 1.6%
For more information, refer to the FILLit Software for Multidrop Combi
nL User Manual (Cat. no. N17562).
To perform a factor calculation:
1. Calculate the correction factor by dividing the expected dispensing
volume (in the factor formula) by the measured volume as follows:
Factor = Expected volume (nl)/Measured dispensed volume (nl)
Factor in the previous example would be 179200 nl/182064 nl =
0.984 ,
which means that the instrument dispenses 0.984 times liquid
compared to the value in the calibration curve. Refer to “Accuracy
check” on page 61.
Factor calculation