Creating Custom Calculations in Clarity Chromatography Software

Custom calculations in Clarity Chromatography Software enable users to extend the functionality of the results table by creating user-defined columns. These columns can perform mathematical or logical expressions based on measured data, user variables, or constants. This feature is essential for laboratories that require automated post-processing of analytical results—such as calculating recovery, purity, correction factors, or other derived parameters.

This guide provides a step-by-step explanation of how to create, edit, and manage custom calculations within the Clarity environment.

Tools and Prerequisites

Before creating user-defined calculations, ensure that the following conditions are met:

• You have access to Clarity Chromatography Software (any edition supporting results table editing).
• A measured dataset or result table is available in the current workspace.
• The user account has permission to edit or create desktop configurations.
• Optionally, user variables are already defined within the analysis or method (e.g., known standards, spiked amounts).

Step-by-Step Procedure

1. Accessing the Results Table

1. Open the chromatogram or sequence results in Clarity.
2. Navigate to the Results Table section in the lower portion of the workspace.
3. Right-click anywhere within the table to display the context menu.

2. Adding a User Column

1. From the context menu, choose User Columns → Add.
2. The Add User Column dialog window appears.
3. In this dialog:
   • Enter a Title for the new column (e.g., Recovery [%]).
   • Optionally specify the Units (e.g., %, mg/L, ng, etc.).
   • Decide whether the Total Value should be automatically calculated for the column (useful for summed data such as total peak areas or concentrations).

3. Defining the Calculation Expression

The central part of the process is defining the mathematical expression used for the calculation.

You can combine:

• Variables – such as Amount, Area, or Retention Time.
• User-defined variables – created earlier via the User Variables feature.
• Functions – such as AVG(), SUM(), ABS(), etc.
• Operators – e.g., +, -, *, /, ^.
• Numeric constants.

Example: Calculation of Recovery

To calculate recovery, where each compound was spiked with a known concentration before analysis:

Amount / RealAmountAdded * 100

In this example:

• Amount represents the detected or measured concentration.
• RealAmountAdded is a user variable defined in the method to represent the spiked amount.
• The result is multiplied by 100 to express recovery as a percentage.

Once entered, click OK or Save to confirm the expression.

4. Viewing and Managing User Columns

After saving, the new user column appears immediately in the Results Table, displaying the calculated value for each compound or row.

To modify or remove an existing user column:

1. Right-click the column header.
2. Select User Column → Edit to revise the formula or settings.
3. Choose User Column → Delete to remove it from the table.

Data Storage and User Settings

The configuration of user columns is stored in the desktop file associated with the user profile.
Key points include:

• Each user account in Clarity has its own desktop configuration by default.
• Desktop files contain layout information, including user columns, report templates, and table customization.
• It is possible to share one desktop file among multiple users, enabling consistent calculations and table views across a team.
• Shared desktops can be configured in the User Account Settings.

This setup ensures reproducibility and uniformity in reporting and data processing within multi-user environments.

Discussion and Best Practices

Implementing user-defined calculations streamlines repetitive post-processing tasks. Instead of manually computing derived values in external software (e.g., Excel), Clarity performs the calculations directly, reducing errors and increasing efficiency.

Recommendations:

• Name user columns descriptively to maintain clarity (e.g., “RelativeArea [%]”, “NormalizedConc [mg/L]”).
• Validate expressions using test datasets before routine application.
• Document all user-defined calculations in method notes for traceability.
• When sharing desktops, establish version control to avoid inconsistencies.

Conclusion

The ability to create custom calculations in Clarity adds flexibility and power to chromatographic data evaluation. By using user columns, laboratories can tailor the data output to specific analytical workflows—whether for recovery calculations, normalization, correction factors, or other custom parameters.

This functionality enhances the interpretability of chromatographic data, simplifies reporting, and ensures consistent data handling across different users and projects.