EM P OW E R 3 SO F T WA R E AU T OMAT E D C US T OM C A L C U L AT IONS
EmpowEr 3 automatEs Custom CalCulations
With Waters® Empower™ 3 Software, you can perform custom calculations, such as percent purity
without relying on external calculations or specialized software programs.
QuEstion:
The routine test for impurities in
our pharmaceutical manufacturing
plant involves calculating the
percent area of active versus
minor contaminants in a batch
of incoming raw material.
Unfortunately, a simple percent
area calculation is not possible.
We must first remove all peaks
with less than 0.05% of the total
area before the final calculation
is made. Must we rely on other
software packages, such as
Microsoft Excel, to perform these
series of calculations on
our collected data?
answEr:
“Custom calculations” have
traditionally been performed using
specialized software programs. Few
chromatography software programs
provide tools that assist you in
reducing raw data to the format you
need to make critical decisions,
such as whether to accept or reject
a particular lot of material.
purity calculations
Chromatographic purity determinations from incoming raw material are frequently performed by
industrial and pharmaceutical organizations before the material is released to production. The
purity calculation measures the percent area of the active component in the mixture.
Frequently, a batch of incoming raw material is accepted if the peak area of an active component
exceeds a certain percentage, typically 95%, from the total peak areas obtained. Difficulties arise
when deciding which peaks qualify for inclusion in the total peak area calculation.
Some measurement protocols require that only peaks with areas greater than 0.05% of the total peak
area be included in the final calculation. In this situation, peaks whose areas are less than 0.05%
of the total must be eliminated before the final percent purity calculation can be determined.
Empower 3 Software provides custom calculation tools that minimize the time, cost, and potential
errors associated with manual calculations, and it eliminates the need to use spreadsheet
calculations from exported chromatography data files.
Figure 2. With Empower 3 Software, you do not need to export
data to other programs for custom calculations.
Figure 1. The Empower 3 Software wizard assists you in creating
custom calculations.
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www.waters.com
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©2006-2010 Waters Corporation. Produced in the U.S.A.
October 2010 720000576EN LB-PDF
How can a chromatography data system eliminate from the final
purity calculation all “minor peaks” whose areas are less than
0.05% of the total peak area? Empower 3 custom calculations
contains various field types and formulae that can be used to
help you to get the right answer faster.
Using the various calculation features of Empower 3 Software, a
variety of fields are created to accomplish the objectives. The first
field tests the percent area for each peak against the 0.05% area
rejection threshold. When the calculated area for an individual
peak is greater than 0.05% of the total peak area, the formula
returns that component’s peak area. When the component’s peak
area is less than or equal to the 0.05% area threshold, the custom
field removes the component from further calculations. Next, the
peaks above the 0.05% threshold are summed so that an adjusted
percent area can be determined.
A final field uses Boolean logic to determine if the percent area
of the active component is greater than 95%; if so, the component
is indicated as ‘passed.’
Table 1 shows the results of these calculations as they appear in
an Empower 3 report. This table compares the original areas and
percent areas prior to the Empower 3 custom calculation (blue box)
with those after the 0.05% area rejection calculations (red box). The
field that determines if the active component passes; is greater than
95% of the total area, is also shown.
aCComplisH Your oBJECtiV Es FastEr witH EmpowEr soFt warE
Table 1. Empower 3 Software’s percent purity custom calculation report.
summary
Empower 3 Software provides the custom calculation tools
necessary for final result calculations, without the time, cost, or
potential errors associated with manual calculations, or the use of
spreadsheet calculations from exported chromatography data files.
Empower 3 Software’s wizard technology helps you generate user
definable calculation criteria to produce validated results without
the need to qualify and maintain specialized application software.
