Metrohm 851 Titrando Coulometric Karl Fischer Titrator

Overview

The Metrohm 851 Titrando is a high-precision, fully automated coulometric Karl Fischer titrator engineered for trace moisture quantification in samples containing ≤100 µg of water. Operating on the electrochemical generation of iodine (I₂) at the anode via Faraday’s law, the system delivers stoichiometrically exact titrant without mechanical burette delivery—eliminating volumetric error and enabling sub-microgram water detection limits. Designed for regulated laboratory environments, the 851 Titrando integrates a patented dead-volume-free coulometric cell, real-time drift compensation, and dual-electrode architecture optimized for stability under low-water-content conditions. Its modular architecture supports seamless expansion into unattended batch analysis workflows, making it suitable for pharmaceutical QC labs, petrochemical R&D, polymer manufacturing, and fine chemical synthesis where compliance with pharmacopoeial methods (e.g., USP , EP 2.5.12) and ISO 760 is mandatory.

Key Features

• Zero-button titration initiation: Sample addition triggers immediate coulometric iodine generation—no manual start command required, preventing background water incorporation and invalid results due to operator delay.
• Intelligent reagent management: Connected via MSB interface to Dosino dispensing modules, enabling fully closed-system reagent replacement without opening the titration vessel. Replacement is triggered by configurable parameters—including cumulative coulombs consumed, elapsed time, drift threshold (>10 µg H₂O/min), or predefined usage count—ensuring consistent reagent activity and minimizing atmospheric moisture ingress.
• Dual control options: Standalone operation via optional high-resolution capacitive touchscreen (with intuitive graphical workflow navigation) or full method development, sequence programming, and audit-trail-enabled data handling via tiamo™ software on Windows-based PCs.
• Bromine number determination: Same coulometric cell and platinum electrodes used for moisture analysis; only solvent and titration parameters require adjustment—no hardware modification or accessory purchase needed. Compliant with ASTM D1159 and IP 127 methodologies.
• Modular automation readiness: Native compatibility with Metrohm 814 and 815 USB sample processors (for up to 100-position unattended analysis) and the 874 Oven Sampler (for thermally released moisture from solids, pastes, or hygroscopic matrices).

Sample Compatibility & Compliance

The 851 Titrando accommodates a broad range of sample types—including oils, solvents, pharmaceutical excipients, polymers, lithium battery electrolytes, and agrochemical formulations—via direct injection, oven coupling, or headspace sampling. All measurement protocols adhere to internationally recognized standards: ASTM D6304 (petroleum products), ISO 760 (general principle), USP (pharmaceutical water content), and EP 2.5.12 (European Pharmacopoeia). The system supports 21 CFR Part 11-compliant electronic signatures and full audit trail functionality when operated under tiamo™ with validated configuration, fulfilling GLP and GMP documentation requirements for regulated industries.

Software & Data Management

tiamo™ software provides comprehensive method development tools, including multi-step titration sequences, conditional logic (e.g., “if drift > X, pause and re-equilibrate”), automatic calculation of water content (ppm or % w/w), statistical reporting (RSD, confidence intervals), and customizable certificate of analysis (CoA) templates. Raw data—including current vs. time curves, drift profiles, and coulombic efficiency logs—are stored in encrypted, non-rewritable format. Export options include CSV, PDF, XML, and LIMS-compatible formats (ASTM E1384, HL7). System validation documentation (IQ/OQ/PQ templates) and change control logs are integrated into the software framework.

Applications

• Pharmaceuticals: Quantification of residual moisture in lyophilized APIs and final dosage forms per ICH Q5C guidelines.
• Petrochemicals: Water content in jet fuel, transformer oil, and biodiesel per ASTM D6304 and IP 386.
• Electronics: Moisture analysis in lithium-ion battery cathode materials and electrolyte solutions—critical for cell longevity and safety.
• Polymers: Determination of hydrolytic degradation extent in polyesters and polyamides via water uptake kinetics.
• Food & Feed: Validation of drying efficacy in milk powders and cereal-based products under ISO 8534.

FAQ

Does the 851 Titrando require calibration with certified water standards?
Yes—coulometric systems must be verified using certified standard solutions (e.g., 1.00 ± 0.01 mg H₂O/mL methanol) to confirm Faraday efficiency and cell response linearity prior to routine use.
Can the same electrode set be used for both moisture and bromine number analysis?
Yes—the dual-platinum generator and indicator electrodes are chemically inert under both KF and bromination reaction conditions; only solvent and titrant chemistry differ.
Is drift correction applied automatically during titration?
Yes—continuous real-time drift subtraction is performed throughout analysis, with user-definable drift stabilization criteria before result acceptance.
What safety provisions exist for handling toxic KF reagents?
The MSB-coupled Dosino module eliminates manual reagent transfer; all fluid paths remain sealed, and waste collection is integrated within the reagent bottle housing.
How is method transfer ensured between instruments?
tiamo™ supports export/import of complete method files—including parameters, sequences, and report templates—enabling identical analytical conditions across multiple 851 Titrando units in multi-site laboratories.