Metrohm 61574210 Dosing Unit for Automatic Potentiometric Titrators

Overview

The Metrohm 61574210 Dosing Unit is a precision-engineered fluidic component designed exclusively for integration into Metrohm’s modular automatic potentiometric titration systems—particularly those utilizing 10 mL exchange units. It functions as a critical interface between reagent reservoirs and the titration burette or between the burette and the titration head, enabling controlled, contamination-free reagent delivery under automated sequence control. Built upon the principles of volumetric precision and chemical inertness, this dosing unit operates within the framework of coulometric and potentiometric titration methodologies compliant with ISO 8655-3 (piston burettes), ASTM E202–22 (standard test methods for analysis by titration), and pharmacopeial requirements including USP and EP 2.2.20. Its role is not measurement per se, but rather the faithful, reproducible transfer of titrant—thereby directly supporting the accuracy, repeatability, and traceability of endpoint determination in quantitative chemical analysis.

Key Features

• Chemically inert fluid path constructed from high-purity FEP (fluorinated ethylene propylene) and ETFE (ethylene tetrafluoroethylene), ensuring zero leaching, minimal adsorption, and compatibility with aggressive reagents—including concentrated hydrochloric acid, perchloric acid, sodium hydroxide, and acetonitrile-based titrants.
• Optically transparent tubing enables direct visual inspection of the entire fluid path, facilitating rapid identification and removal of air bubbles—a primary source of volumetric error in automated titration.
• Precision-length design calibrated specifically for seamless integration with Metrohm’s 10 mL exchange modules; prevents excessive dead volume (which compromises rinse efficiency and cross-contamination control) and eliminates mechanical strain on actuation components.
• M6 metric thread interface conforms to Metrohm’s proprietary mechanical standard, guaranteeing repeatable sealing performance and interchangeability across generations of 800/900/910 series titrators and OMNIS platforms.
• Low surface energy and smooth inner bore minimize residual carryover and support efficient rinsing protocols required under GLP and GMP environments.

Sample Compatibility & Compliance

This dosing unit supports universal application across aqueous, non-aqueous, and mixed-solvent titration matrices. It is routinely deployed in applications involving acid-base, redox, complexometric, and precipitation titrations—fully compatible with Metrohm’s wide range of standardized titrants (e.g., 0.1 mol/L HCl, 0.1 mol/L NaOH, 0.05 mol/L AgNO₃). Its material certification meets FDA 21 CFR 177.1550 (fluoropolymer indirect food additives) and EU Regulation (EC) No 1935/2004 for food contact materials. When used within validated Metrohm titration workflows, it contributes to full compliance with ISO/IEC 17025:2017 (clause 6.4.3 on equipment suitability) and supports audit-ready documentation under 21 CFR Part 11 when paired with tiamo™ or OMNIS software.

Software & Data Management

The 61574210 unit requires no standalone firmware or calibration—it is fully transparent to Metrohm’s tiamo™ and OMNIS software suites. Its operational parameters are managed implicitly through method-defined dosing sequences, syringe positioning, and purge cycles. Software-controlled “Prep” routines automatically prime the line, detect flow continuity, and log status events (e.g., “Line primed”, “Bubble detected”) with timestamps and operator ID—enabling full electronic record retention per ALCOA+ principles. Audit trails include configuration changes, maintenance alerts (e.g., “M6 seal wear suspected”), and system diagnostics—all exportable in CSV or PDF for regulatory submission.

Applications

• Quality control of raw materials and finished pharmaceutical products (e.g., assay of active ingredients via acid-base titration per USP monographs).
• Water and wastewater analysis: chloride determination (Mohr method), alkalinity profiling, and hardness testing (EDTA complexometry).
• Food & beverage testing: titratable acidity in wines and dairy, sulfite quantification in juices, and free fatty acid analysis in edible oils.
• Electrolyte formulation in battery R&D: precise acid/base addition during electrolyte synthesis and impurity titration (e.g., HF scavenging verification).
• Academic research requiring high-fidelity reagent delivery in kinetic or multi-step titration protocols.

FAQ

Is the 61574210 dosing unit compatible with non-Metrohm titrators?
No—it is mechanically and functionally optimized for Metrohm’s proprietary exchange unit architecture and M6 interface; third-party integration is not supported.
What maintenance intervals are recommended for the FEP/ETFE tubing?
Inspect visually before each use; replace after 6 months of continuous operation or immediately following exposure to crystallizing reagents (e.g., >0.5 mol/L NaOH) without post-run rinsing.
How does this unit contribute to measurement uncertainty budgets?
By minimizing dead volume, eliminating adsorption artifacts, and enabling reliable bubble detection, it reduces Type B uncertainty contributions associated with volumetric delivery—typically improving overall titration repeatability (RSD) by ≤0.15% under controlled conditions.
Can it be autoclaved?
No—FEP/ETFE is not rated for steam sterilization; cleaning must be performed using solvent flushes or ultrasonic baths with compatible media.
Does Metrohm provide a certificate of conformance?
Yes—each unit ships with a manufacturer’s CoC referencing material traceability (ASTM D4894), dimensional verification, and chemical resistance validation per ISO 17025-accredited internal testing.