Method Dilution in Waters Arc HPLC System

Svetlana Chechik, QC, Teva, Kfar Saba, Israel (Svetlana.Chechik@teva.co.il)
Jasmin Nasser, Qc, Teva, Kfar Saba, Israel
Ronit Sherman, Qc, Teva, Kfar Saba, Israel

• Automated sample dilution in the Waters Arc HPLC system is compared to the traditional manual dilution method.
• The system enables accurate, reproducible dilution directly on the instrument, minimizing manual handling and potential errors.

Due to the elimination of the dilution step, for tests like Uniformity of Content or Assay, several savings are expected: 

Time Savings: At least 1 working hour saved per test (~12.5% of analyst time)

Reduced Reagent & Solvet Use: Less consumption of chemicals and materials

Lover Glassware Usage: Fewer tubes, vials, and cleaning steps required

Improved Accuracy: Fewer manual steps reduce the risk of human error, increasing Right First Time (RFT) rates

Key Parameters in Automated Sample Dilution (Waters Arc HPLC System)

Automated dilution uses precise control of parameters: mix stroke volume, mix cycle and syringe draw rate.

Mix Stroke Volume

Defines the volume of liquid moved by the syringe in a single mixing stroke.

Ensures thorough mixing and homogeneity of the diluted solution before injection.

Mix Cycles

Number of times the system mixes the sample and diluent during dilution.

Each cycle involves drawing and dispensing liquid to achieve uniform mixing.

Syringe Draw Rate

Controls the speed at which the syringe draws liquid (sample or diluent).

Optimized to ensure accuracy, consistency, and to prevent bubble formation.

CONCLUSION

Efficiency: Automated dilution simplifies workflow and saves time.

Accuracy: Comparable to manual dilution, with consistent and reproducible results.

Reliability: Reduced operator-dependent variability and risk of error.