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To Query or Not to Query – That Is the Question

Team TFS
Team TFS
chromeleon“Half of science is putting forth the right questions.” -- Francis Bacon

Laboratory operators ask and are asked questions every day:

  • Does this material meet the specification? Is it fit for its intended use?

  • Is our product safe for the end-user?

  • How many injections has this instrument done this month?

  • Which column was used for analysis?

  • How much manual integration has the lab done this month?

  • Have all sequences been reviewed and signed this month?

  • Is the data collected reliable, accurate, scientifically sound?

  • Are all reported records complete and accurate?

Remember Chromatography Data System (CDS) users come in a lot of different guises, for example, technician, analyst, reviewer, QA, administrator, internal and external auditor to name but a few. Each has their own questions and requirements for CDS data.

As I’m sure many of you know, enables users to form questions as a logical argument or Query and use that to search the data for answers and insights. But don’t forget, regulatory auditors also know about Queries, what they can be used for, and can request you use them during an audit.

The Basics

A Chromeleon Query is a logical argument that can be used to search through data. The example below uses the ‘Quick Search Criteria’ to retrieve all injections in a selected time range.

First, choose the category either ‘Injection’ or ‘Sequence.’

The variable is then selected, in this case, ‘Inject Time,’ followed by the comparison operator ‘is between’ which in this case then gives two date and time boxes to enter the start and end dates/times.

The values presented depend upon the category, variable and comparison operator as shown in the table below:


First, choose the category either ‘Injection’ or ‘Sequence.’

The variable is then selected, in this case ‘Inject Time,’ followed by the comparison operator ‘is between’ which in this case then gives two date and time boxes to enter the start and end dates/times.

The values presented depend upon the category, variable and comparison operator as shown in the table below:


A comprehensive list of the variables and operators can be found in the help section of Chromeleon CDS, but once you start to create Queries, they are pretty much self-explanatory as you can only select relevant variables and operators.

Finally hit ‘Search’ and the Query will run and return the results in a virtual sequence below the Query pane.

But Chromeleon CDS Queries are smarter than that!

You can set multiple criteria to narrow your search results.

First, you should decide whether to match ‘All’ or ‘Any’ of the criteria, where:

  • ‘All’ is the equivalent of the AND logical operation

  • ‘Any’ is the equivalent of the OR logical operation


This Query looks for any sequences where the instrument used is QC_LC55 but only during the last 12 months.  More arguments can be added to the Query, for example, if we only wanted to see the injections of calibration standards made on this instrument in the same period we can just add another criteria that the injection type must equal ‘Calibration Standard’:


Tip: The ‘Sequence Directory’ parameter is useful to restrict the search to a specific folder (or folders) in the Data Vault rather than searching the entire Data Vault, which can be quite time consuming if there is a large amount of data there!

One Step Further

So far, we have only used the ‘Quick search Criteria.’ Another category called ‘Computed Criteria’ can also be added to the query. These criteria are especially useful for finding injections based on calculated results, for example, peak areas or component amount.

The Query below looks for calibration standard injections made in the last 12 months that contain a peak named ‘compound1’ with an area of 500 to 1000 area units.


You can start to see how a Query can be tailored to find specific data.

Queries: What Are They Good For?

Queries can be very useful for searching for many things, for example, we use them to find (among other things):

  • Analytical column numbers (this information is entered in a custom variable)

  • Ambiguous sample injection names

  • Repeat injections (authorized or otherwise)

  • Numbers of deviations and investigations

  • Number of manual integrations

  • Injection status – signed, reviewed, approved


Use of Chromeleon Queries in manual integration monitoring was discussed in my previous blog post ‘What's Wrong With Manual Integration,’ so I will take a different example from the list above as an area for regulatory concern: ‘Ambiguous sample injection names.’

What if an auditor asked you the question, “Can you show me any injections called ‘Trial’ or ‘Settle’ or ‘Test’?” How many hits do you think you would you get? As we all know trial injections of samples are forbidden under GxP regulation so this is one example of where we can use Chromeleon Queries to demonstrate or be asked to demonstrate compliance.

David Churchward wrote an interesting article on this on the MHRA blog.

The Future

Sterling is striving to use Chromeleon CDS to its fullest, and we are part way through a project to implement the use of electronic signatures and electronic reports across all our laboratories. So far, we currently electronically sign all final product and release analysis (submit and review), and Queries are a key component of this initiative. They are used to check all sequences have been signed and we are then able to generate a key performance indicator for the project.


As you can see, we achieved our first target in December 2019. Our lab-wide target is 100% signoff for all sequences generated with a target of January 2021.

We are also looking at the latest innovations in Chromeleon 7.3 CDS – Audit Trail Queries and Audit Trail Events.

The Audit Trail Events are designed to capture and highlight compliance-related events in the Data Audit Trail (the history of the data) such as sequence interruptions, manual integrations or in-run instrument parameter changes, bringing together the Instrument Daily Audit Trail and the Data Audit Trail, enabling reviewers to identify possible compliance issues much more quickly during their normal sequence review procedure.

The new Query tool allows you to very quickly search audit trails for any existing information plus the Audit Trail Events giving administrators and QA a powerful new tool to monitor and demonstrate compliance - especially useful when you’re in front of an auditor!

Questions, Question, Questions

Queries are an often overlooked element of Chromeleon CDS but hopefully, you can see how they can be of value to any user, from an analyst checking what an analytical column or instrument was last used for, to regulatory auditors searching for data integrity issues.

Remember, even if you don’t use them, auditors can and will!

Find out more about Sterling Pharma Solutions and the services they offer here.
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