METTLER TOLEDO EasyPlus ET08 Coulometric Karl Fischer Moisture Titrator

Overview

The METTLER TOLEDO EasyPlus ET08 is a fully automated coulometric Karl Fischer titrator engineered for high-precision, trace-level moisture determination in laboratories requiring regulatory compliance and operational robustness. Based on the electrochemical generation of iodine via controlled current (Faraday’s law), the ET08 quantifies water content by measuring the total charge required to oxidize iodide to iodine in an anhydrous methanol-based electrolyte system. This principle ensures exceptional sensitivity—down to 1 ppm—and linear response across the full dynamic range from 1 ppm to 100% w/w water. Unlike volumetric KF systems, coulometric operation eliminates reagent standardization drift and pipetting variability, delivering superior reproducibility for low-moisture samples such as pharmaceutical excipients, lithium battery materials, polymers, and hygroscopic solvents. The instrument integrates seamlessly into quality control workflows governed by USP , EP 2.5.12, ASTM E203, and ISO 760, supporting routine validation and method transfer.

Key Features

• Coulometric titration mode with microcurrent-controlled iodine generation (0–200 mA), enabling sub-ppm detection limits and minimal reagent consumption.
• Smart iTitrate guidance system: context-aware, application-driven parameter setup that auto-suggests optimal current limits, endpoint thresholds, and stirring speeds based on sample type and expected moisture level.
• Dedicated liquid sampling interface featuring a sealed septum port and precision syringe adapter—minimizes atmospheric moisture ingress during injection and supports repeatable 10–100 µL dosing.
• Ergonomic weighing boat design with integrated lip and anti-spill geometry—optimized for accurate, spill-free handling of powders, granules, and hygroscopic solids on integrated analytical balances (e.g., METTLER TOLEDO XSR/XSE series).
• Automatic titrant concentration verification using certified water standards—performed without manual intervention or external calibration solutions.
• Modular hardware architecture with replaceable generator and indicator electrodes, enabling rapid maintenance and extended service life under continuous QC use.

Sample Compatibility & Compliance

The ET08 accommodates diverse sample matrices—including organic solvents (acetone, THF, chloroform), solid APIs, tablet coatings, catalysts, silica gels, and polymer pellets—via optional sample preparation kits (e.g., oven coulometric adapters, headspace vials, and hydrolysis cells). All wet chemistry modules comply with IEC 61000-4 electromagnetic immunity standards and feature PTFE/glass fluidic paths resistant to aggressive KF reagents. Data integrity is maintained per FDA 21 CFR Part 11 requirements through built-in electronic signatures, time-stamped audit trails, and password-protected method editing. Instrument qualification documentation (IQ/OQ/PQ protocols) and GxP-ready reports are exportable in PDF and CSV formats.

Software & Data Management

Controlled via METTLER TOLEDO’s titration-specific EasyDirect™ Titration software (v3.5+), the ET08 supports real-time titration curve visualization, multi-parameter method storage (up to 100 methods), and automatic calculation of water content (mg H₂O, % w/w, ppm) with uncertainty propagation. Data export options include direct USB printing to METTLER TOLEDO USB-P25 thermal printers and secure network transfer to LIMS or ELN systems via OPC UA or FTPS. All raw data—including current vs. time profiles, endpoint detection logic, and balance synchronization logs—are retained with immutable timestamps and user attribution.

Applications

• Pharmaceutical QC: Residual moisture in lyophilized products, active ingredients, and excipients per USP and ICH Q5C guidelines.
• Battery materials: Water quantification in LiCoO₂, NMC cathodes, and electrolyte salts where >20 ppm H₂O induces HF formation.
• Chemical manufacturing: Moisture monitoring in silicone fluids, epoxy resins, and isocyanate prepolymers to prevent gelation or side reactions.
• Food & feed analysis: Direct determination of water in spices, dairy powders, and pet food without solvent extraction artifacts.
• Research labs: Method development for novel KF-compatible solvents and non-aqueous sample dissolution protocols.

FAQ

What is the minimum detectable water mass using the ET08?
The coulometric cell achieves a theoretical detection limit of 0.1 µg H₂O (based on 1 µC = 0.125 µg H₂O), with practical repeatability confirmed at ≤1 µg under optimized conditions.
Can the ET08 be used with non-METTLER TOLEDO balances?
Yes—the instrument supports RS232 and USB-HID communication with most GLP-compliant analytical balances meeting ISO 17025 traceability requirements.
Is method validation support included?
Pre-validated IQ/OQ templates, linearity verification protocols (1–1000 µg water), and robustness testing checklists are provided in the installation qualification package.
How often must the generator electrode be cleaned or replaced?
Under typical usage (≤20 samples/day), the platinum generator electrode requires cleaning every 2–3 weeks with concentrated nitric acid; lifetime exceeds 12 months with proper maintenance.
Does the ET08 meet ASTM D6304 requirements for petroleum products?
While primarily designed for coulometric applications, optional oven coupling modules enable compliance with ASTM D6304 Annex A2 for volatile and viscous hydrocarbons.