Automated Sample Handling and Analysis With NOVA: Standard addition with the Metrohm 800 Dosino

Importance of the Topic

Automated liquid handling is a cornerstone of modern analytical chemistry workflows, ensuring high throughput, reproducibility, and minimal human error. The integration of dosing systems with electrochemical analyzers expands the range of possible experiments by enabling precise standard additions and sample manipulations in a fully automated sequence.

Objectives and Study Overview

This application note demonstrates how to combine the Metrohm 800 Dosino with the NOVA software and Autolab potentiostat systems for standard addition experiments. The goal is to illustrate a practical procedure for determining trace metal concentrations, using zinc in tap water as a model analyte.

Methodology and Instrumentation

A differential pulse voltammetry experiment is embedded in a NOVA procedure with a three-cycle repeat loop. After each voltammetric measurement, the Dosino dispenses 100 microliters of zinc standard into the electrochemical cell. The generated voltammograms are processed to extract peak currents, which are plotted against added standard concentration for regression analysis.

Instrumentation

• Metrohm 800 Dosino (Drive Unit with exchangeable Dosing Units, volumes from 2 to 50 mL)
• Metrohm 814, 815 or 858 Sample Processor or Metrohm 846 Dosing Interface
• Autolab PGSTAT302N potentiostat connected via IME663 to Metrohm 663 VA Stand
• Mercury drop working electrode
• NOVA software for instrument control and data analysis

Key Results and Discussion

The standard addition experiment for zinc in tap water produced clear differential pulse voltammograms. Plotting peak height versus added zinc concentration yielded a linear regression described by y=6.30E-8+3.33E-4x. Extrapolation to zero signal provided a zinc content of 189.2 micrograms per liter in the sample.

Benefits and Practical Applications

• Fully automated dosing reduces manual pipetting errors and saves operator time.
• Software integration allows seamless control of dosing, measurement, and data processing in one environment.
• Standard addition workflows benefit QA/QC protocols by correcting for matrix effects in complex samples.

Future Trends and Opportunities

Advances in automation will likely incorporate adaptive dosing routines driven by real-time data analysis and machine learning. Integration with microfluidic platforms and multiplexed detection methods can further enhance throughput. Expansion to other electroanalytical techniques, such as impedance spectroscopy or flow injection analysis, is anticipated.

Conclusion

The coupling of the Metrohm 800 Dosino with NOVA and Autolab instruments enables robust and reproducible standard addition workflows. This approach streamlines trace analysis, improves data quality, and simplifies method implementation for routine laboratory operations.

References

1. Application Note AN-AUT-002, Automated Sample Handling and Analysis With NOVA: Standard addition with the Metrohm 800 Dosino, Metrohm, April 2019