Overview
Chemical Solutions™ HSQ™, PQ™, and UV-Vis Qualification Kits are designed to provide reliable and reproducible qualification testing. In some situations, laboratories may have qualification solutions from multiple manufacturing lots and need to determine whether they can be used together.
The answer depends on which solutions are being combined.
Acceptable Use of Different Lot Numbers
Qualification solutions from different lots may be used together when the solutions serve different qualification functions.
For example:
- L1-L6 linearity solutions from one lot
- Holmium Oxide (HOX) solution from a different lot
- Other qualification standards from different lots
This approach is acceptable provided each individual solution remains within its expiration period and is suitable for use. Many laboratories use this strategy to maximize solution utilization when certain components have longer expiration dates than others.
Requirements for L1-L6 Linearity Standards
The L1-L6 linearity standards are treated differently.
These solutions are manufactured, tested, and certified as a matched set.
Because detector linearity testing depends on the precise concentration relationships among the standards, the L1-L6 solutions should always originate from the same lot.
Do not combine:
- L1 from one lot with L2-L6 from another lot
- Partial linearity sets from different lots
- Mixed linearity standards from multiple qualification kits
Maintaining a single-lot linearity set helps ensure valid qualification results.
Why Lot Consistency Matters
The L1-L6 solutions are used to evaluate detector linearity across a defined concentration range.
The relationship between these solutions is critical when generating:
- Calibration curves
- Linearity assessments
- Detector performance evaluations
- Qualification documentation
Using standards from different lots within the same linearity series may compromise the intended concentration relationships and affect the reliability of the qualification data.
Best Practice Recommendations
For the most straightforward qualification process:
- Use complete qualification kits whenever possible.
- Keep L1-L6 solutions together as a matched set.
- Verify expiration dates before use.
- Document all lot numbers used during qualification.
- Replace incomplete linearity sets with a matching replacement set when necessary.
These practices help support consistent qualification performance and simplify documentation.
Key Takeaways
- Different qualification solution lots may be used together when the solutions serve different functions.
- Holmium Oxide and other qualification standards may originate from different lots.
- L1-L6 linearity standards must remain from the same lot.
- Mixed-lot linearity sets should not be used.
- Maintaining matched linearity standards helps preserve qualification accuracy and data integrity.
- Using complete qualification kits helps simplify compliance and documentation.