Tip #78, Reader question: How do you quantitate impurities against the main component?

Welcome back to Get Empowered! In the last Empower tip-of-the-week post for Empower Software, we answered a submitted reader question and learned how to summarize specified and unspecified impurities in a sample and quantitate them against the main component. (Tip #77)  (See the link at the bottom of our post to ask your own question, or to provide a tip of your own!)

In this week’s tip, I will answer another question pertaining to calculating impurities.

Question: How do you quantitate impurities against the main component?

Another great question and there are two possible scenarios.

Let me show you how it is done.

Step 1

If the impurities are listed in the Components tab of the Processing Method, go to the Curve Reference field and select the API/main component for the impurity (or impurities) so that Empower Software quantitates the impurities against the calibration curve for the main component.  The Relative Response field is used to multiply the calculated amount by a factor, the default is 1 (Figure 1).

Figure 1

Step 2

If the impurities are not listed in the Components tab of the Processing Method, go to the Default Peak field and check the box for the API/main component.  Then set the Default Start and Default End fields to include the time frame in which the impurities elute.  Any peaks that elute in that region will be quantified against the calibration curve for the API (Figure 2).

Figure 2

Step 3

Go to the Impurity tab and set the Impurity Response to Amount. Select the API as the Main Component. You can then set the ICH Thresholds as per your SOP (Figure 3).

Figure 3

Step 4

Quantitate the sample. We see the Amount of impurities calculated in the sample (Figure 4).

Figure 4

It’s that easy!

Final Note:  This procedure can be followed using the QuickStart or Pro interface.

Please rate this Empower Tip of the Week

Previous questions we’ve answered:

• How can I calculate the ratio of peak height to valley height when I have a valley point between peaks?
• Why is the retention time of my peak slightly different than the retention time of the UV apex spectrum for the peak?
• How do you calculate impurity response when there are two APIs in the sample?
• How do you summarize specified and unspecified impurities in a sample and quantitate them against the main component?

Next week in Empower Tip #79 – More answers to questions from our readers

 More resources:

• Want to learn more? Check out our Empower training courses and eLearning.
• Build your technical skills and professional network. Share, ask, and interact with peers from around the globe in dynamic discussions by joining our Informatics Community Forum.
• Empower is the first cloud-deployable, compliance-ready, enterprise chromatography data software – Learn more about Empower Cloud
• Get the latest Empower projects, options, and more. Check out the New Waters Marketplace.
• See all of our tips for using Empower CDS Software.