EMPOWER 3 SOFTWARE AUTOMATED CUSTOM CALCULATIONS

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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Milford, MA 01757 U.S.A. 
T: 1 508 478 2000 
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www.waters.com

Waters is a registered trademark of Waters Corporation. Empower and  
The Science of What’s Possible are trademarks of Waters Corporation.  
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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.