Comprehensive water analysis with TitrIC Vario pro III

Significance of the Topic

Comprehensive water analysis is essential for ensuring public health, meeting regulatory standards, and protecting natural resources. Integrating titration with ion chromatography streamlines multi-parameter assessment, reducing analysis time and enhancing data consistency.

Objectives and Study Overview

This application note presents an automated method using the TitrIC Vario pro III platform to determine pH, conductivity, hardness, major anions and cations, and ion balance in drinking water within a single sequence. The approach aims to deliver accurate, high-throughput results for routine water quality monitoring.

Methodology and Instrumentation

• Sample protocol
  • Matrix: Untreated drinking water
  • Preparation: Direct injection, no pretreatment required
• Ion Chromatography
  • Anions: Metrosep A Supp 5-150/4.0 column, eluent 3.6 mmol/L Na2CO3 + 1.0 mmol/L NaHCO3, suppressed conductivity detection, flow 0.7 mL/min, injection volume 20 μL, runtime 17 min, column temp. 30 °C
  • Cations: Metrosep C 4-150/4.0 column, eluent 1.7 mmol/L HNO3 + 0.7 mmol/L dipicolinic acid, non-suppressed conductivity detection, flow 0.9 mL/min, injection volume 10 μL, runtime 20 min, column temp. 30 °C
• Titration
  • Technique: Potentiometric titration in SET mode
  • Titrant: 0.1 mol/L HCl
  • Endpoints: m-value (total hardness), p-value (acid capacity), temperature tracking
  • Sensors: pH electrode iAquatrode plus, flow-through conductivity cell
• Automation and Control
  • 940 Professional IC Vario TWO with MagIC Net software
  • 815 Robotic UBS Sampler XL with Swing Head arms for sample handling
  • 800 Dosino dosing units, 802 Stirrer, 905 Titrando, 856 Conductivity Module

Key Results and Discussion

Analyzed drinking water sample yielded the following:

• Anions and cations determined by IC: fluoride 0.05 mg/L, chloride 10.02 mg/L, nitrate 9.52 mg/L, sulfate 5.40 mg/L, sodium 5.90 mg/L, potassium 1.48 mg/L, calcium 92.84 mg/L, magnesium 20.92 mg/L
• Calculated parameters by titration: total hardness 3.2 mmol/L, acid capacity (m value) 6.1 mmol/L, pH 7.7, conductivity 523.2 μS/cm
• Sum of anions 0.55 mEq/L (IC) and 6.10 mEq/L (titration), sum of cations 6.65 mEq/L, ion balance 0.00 mEq/L

Results demonstrate high agreement between chromatographic and titrimetric data, with ion balance close to zero indicating reliable quantification.

Benefits and Practical Applications

• Unified workflow reduces the need for multiple instruments and sample transfers
• Fully automated operation increases throughput and reproducibility
• Comprehensive data set supports regulatory compliance and quality assurance in water treatment and distribution
• Flexible configuration allows customization for specific analyte panels

Future Trends and Opportunities

Advancements may include expanded analyte libraries, integration of inline sensors for continuous monitoring, microfluidic enhancements to reduce reagent consumption, and implementation of AI-driven data analysis for predictive maintenance and decision support in water management systems.

Conclusion

The TitrIC Vario pro III platform offers a robust and efficient solution for all-in-one water quality analysis. By coupling ion chromatography with potentiometric titration in a single automated workflow, laboratories can achieve accurate, reproducible results with minimal operator intervention.

Reference

• Metrohm Application Note S-300: Comprehensive Water Analysis with TitrIC Vario pro III, Version 2.