HOGON CT-1Plus Automatic Potentiometric Titrator for Transformer Oil Acid Number Determination

Overview

The HOGON CT-1Plus Automatic Potentiometric Titrator is an integrated, modular analytical platform engineered for high-reproducibility potentiometric titrations in regulated and routine laboratory environments. Designed specifically to meet the stringent requirements of transformer oil acid number (AN) determination per ASTM D974 and IEC 62021-1, the instrument operates on the principle of potentiometric endpoint detection—measuring the inflection point in electrode potential (mV) versus titrant volume during controlled addition of standardized alcoholic KOH solution. Its architecture combines a precision stepper-motor-driven burette system, a low-drift Ag/AgCl reference electrode interface, and real-time electrochemical signal acquisition at 10 Hz sampling frequency. Unlike manual or semi-automated methods, the CT-1Plus eliminates subjective visual endpoint interpretation by applying second-derivative (d²E/dV²) algorithmic analysis to identify stoichiometric equivalence points with sub-microliter volumetric resolution. This ensures compliance with ISO/IEC 17025 method validation criteria for repeatability (RSD < 0.5% for AN ≤ 0.1 mg KOH/g) and intermediate precision across operator shifts.

Key Features

• Modular hardware design supporting dual-mode operation: potentiometric titration (pH, redox, precipitation, complexometric) and photometric (colorimetric) titration via optional LED-based color sensor module
• High-precision burette system: standard 20 mL glass syringe-type burette with 0.001 mL dispensing increment; optional 10 mL burette offering 0.0005 mL resolution for trace-level applications
• Electrochemical measurement unit calibrated to NIST-traceable standards: ±0.2 mV absolute accuracy over ±2000 mV range, 0.1 mV display resolution, stable baseline drift < 0.3 mV/h
• Intelligent endpoint recognition using dynamic slope-threshold and curvature-based algorithms—eliminates reliance on fixed pH thresholds or user-defined windows
• 7-inch capacitive touchscreen interface with physical keypad backup; supports multilingual UI (English, Chinese, Spanish) and customizable method templates
• GLP/GMP-compliant data integrity framework: electronic signatures, full audit trail (user actions, method changes, calibration logs), and tamper-evident PDF report generation with embedded digital signatures and UVC-compatible QR codes

Sample Compatibility & Compliance

The CT-1Plus accommodates sample volumes from 10–50 g (typical for transformer oil AN testing per ASTM D664 and D974), compatible with non-aqueous solvents including 1-propanol/toluene mixtures and chlorobenzene-based media. Electrode compatibility includes standard double-junction pH electrodes, platinum redox electrodes, silver/silver chloride titration electrodes, and ion-selective membranes for halide or sulfide analysis. The system conforms to regulatory data governance requirements under FDA 21 CFR Part 11 (electronic records and signatures), EU Annex 11 (computerized systems), and ISO 17025:2017 clause 7.7 (result reporting). All firmware and software revisions undergo formal change control and version-locking to ensure method consistency across instrument deployments.

Software & Data Management

Equipped with HOGON TitrSoft v3.2 analytical software, the CT-1Plus enables method development, sequence programming, real-time curve overlay (E-V, dE/dV, d²E/dV²), and automated report compilation. Data export supports CSV, XML, and PDF formats with embedded metadata (sample ID, operator, timestamp, environmental conditions, calibration history). Local storage retains ≥10,000 titration records with automatic daily backup to encrypted USB drives. Network-enabled models support secure LAN integration with LIMS via ASTM E1384-compliant messaging protocols. Audit trails are immutable and time-stamped to UTC, meeting ISO/IEC 17025 clause 7.9 requirements for result traceability.

Applications

Beyond transformer oil acid number quantification, the CT-1Plus delivers validated performance in multiple regulated workflows: acid value and base number determination in lubricants (ASTM D664, D2896); peroxide value and free fatty acid analysis in edible oils (AOCS Cd 8b-90, ISO 3960); chloride content in pharmaceutical excipients (USP ); water content via Karl Fischer titration (ASTM D6304); and redox titrations for iron, copper, or manganese in metallurgical samples. Its flexibility extends to academic research in corrosion inhibitor evaluation, biodiesel quality assessment (EN 14104), and environmental monitoring of organic acid leachates in soil extracts.

FAQ

What standards does the CT-1Plus support for transformer oil acid number testing?
It fully complies with ASTM D974 (color-indicator method), ASTM D664 (potentiometric method), and IEC 62021-1 for insulating oil testing.
Can the instrument perform Karl Fischer titration without hardware modification?
Yes—KF functionality is enabled via software license activation and requires only a dedicated KF reagent dispenser module and oven-controlled sample stage (optional accessories).
Is method validation documentation available for regulatory submissions?
HOGON provides IQ/OQ/PQ protocols, uncertainty budgets per EURACHEM/CITAC Guide, and GxP-aligned validation templates upon request.
How is data integrity maintained during power interruption?
The system features non-volatile memory with auto-save every 0.1 mL dispensed; all active titrations resume from last saved state after reboot.
Does the CT-1Plus support remote diagnostics and firmware updates?
Yes—secure SSH-enabled remote access allows authorized service engineers to diagnose hardware status, calibrate sensors, and deploy verified firmware patches without onsite visits.