Yoke ZD-3A Automatic Potentiometric Titrator
| Brand | Yoke |
|---|---|
| Origin | Shanghai, China |
| Manufacturer Type | Direct Manufacturer |
| Model | ZD-3A |
| Instrument Category | General-purpose Potentiometric Titrator |
| Application Scope | Universal |
| pH Range | −2.00 to 20.00 pH |
| mV Range | −1999 to +1999 mV |
| Temperature Measurement Range | −5.0 to 105.0 °C |
| pH Resolution | 0.01 pH |
| mV Resolution | 0.1 mV |
| Temperature Resolution | 0.1 °C |
| pH Accuracy | ±0.03 pH |
| mV Accuracy | ±0.03% FS |
| Temperature Accuracy | ±0.3 °C |
| Input Current | ≤2 × 10⁻¹² A |
| Input Impedance | ≥3 × 10¹² Ω |
| Stability (Electronic Unit) | (±0.3 mV ±1 digit)/3 h |
| Endpoint Setting Range | −2.00–20.00 pH or −1999–+1999 mV |
| Titration Control Sensitivity | ±0.1 pH or ±5 mV |
| Repeatability (Volumetric Analysis) | 0.2% |
| Data Storage Capacity | 2000 records |
| Storage Content | Sample name, endpoint value, concentration, date & time |
| Operating Environment | 5–40 °C, ≤85% RH |
| Power Supply | AC 220 V ±10%, 50 Hz ±0.5 Hz |
Overview
The Yoke ZD-3A Automatic Potentiometric Titrator is a benchtop electrochemical analyzer engineered for precision volumetric analysis based on potentiometric endpoint detection. It operates on the fundamental principle of monitoring potential change (in mV) or pH shift across a redox, acid–base, precipitation, or complexometric titration reaction—enabling accurate determination of equivalence points without reliance on visual indicators. Designed for routine and research-grade applications in academic laboratories, environmental monitoring centers, petrochemical QA/QC departments, and municipal water testing facilities, the ZD-3A delivers reproducible results under GLP-aligned workflows. Its integrated architecture combines a high-impedance potentiometric amplifier, microprocessor-controlled dosing system with solenoid valve actuation, and built-in magnetic stirring—eliminating external controller dependencies and minimizing inter-unit variability.
Key Features
- 7-inch capacitive touchscreen (1024 × 600 resolution) with adjustable brightness and intuitive icon-driven navigation—optimized for glove-compatible operation and multi-user environments.
- Integrated magnetic stirrer and titration module in a single chassis—reducing footprint, cable clutter, and mechanical misalignment risks during long-duration titrations.
- Automatic electrode calibration (1–3 point) with NIST-traceable buffer recognition; real-time temperature compensation using integrated Pt1000 sensor (−5.0 to 105.0 °C).
- Three operational modes: manual titration (stepwise addition), automatic titration (predefined volume increments), and controlled titration (endpoint held at user-defined pH or mV threshold with delay timing).
- Endpoint detection algorithms support both fixed-potential termination and dynamic slope-based equivalence point calculation—adaptable to slow-reacting or multi-step titrations.
- Comprehensive self-diagnostic suite including electrode impedance check, liquid path blockage alert, and voltage drift logging—facilitating preventive maintenance and audit readiness.
Sample Compatibility & Compliance
The ZD-3A accommodates standard combination pH electrodes, redox (Pt or Ag/AgCl) electrodes, ion-selective electrodes (e.g., fluoride, chloride), and custom reference systems via BNC and mini-DIN connectors. Its high-input-impedance circuitry (≥3 × 10¹² Ω) ensures minimal loading error with high-resistance glass membranes, while ultra-low input current (≤2 × 10⁻¹² A) preserves signal integrity during trace-level analyses. The instrument meets general requirements for electrochemical instrumentation per IEC 61010-1 (Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use). Though not certified to ISO/IEC 17025 or FDA 21 CFR Part 11 out-of-the-box, its data export protocols (CSV via USB), timestamped audit trail (date/time-stamped endpoint logs), and non-volatile storage support validation efforts under GLP and internal QA frameworks. All stored data—including sample ID, endpoint value, calculated concentration, and operator timestamp—are exportable to Excel-compatible CSV files without proprietary software dependency.
Software & Data Management
Data acquisition and reporting are managed entirely through the onboard embedded OS—no PC connection required for routine operation. Each measurement record stores up to 2000 entries locally in non-volatile memory, retaining full metadata: sample identifier, titrant concentration, endpoint pH/mV, calculated result, ambient temperature, and execution timestamp. Export is performed via standard USB-A port to FAT32-formatted USB drives; no drivers or vendor-specific utilities needed. Optional wireless thermal printing (via Bluetooth 4.2) enables on-demand hardcopy generation compliant with lab notebook retention policies. Cloud synchronization is available through optional Yoke CloudLink firmware (v2.1+), enabling remote configuration backup, centralized instrument fleet monitoring, and encrypted data upload to customer-hosted SFTP servers—supporting distributed lab networks operating under ISO 9001 or CAP-accredited quality systems.
Applications
- Determination of total acidity and alkalinity in wastewater and drinking water per APHA Standard Methods 2320B and EPA Method 310.1.
- Quantification of chloride in crude oil and refined fuels following ASTM D4294 and IP 287 protocols using potentiometric silver nitrate titration.
- Acid number (AN) and base number (BN) analysis in lubricants and transformer oils per ASTM D664 and D2896.
- Calcium and magnesium hardness titration in industrial cooling water using EDTA and Calcon indicator-free methodology.
- pH-stat titrations for enzyme kinetics studies and buffer capacity characterization in biochemical research.
- Quality control of pharmaceutical excipients (e.g., citric acid, sodium bicarbonate) per USP and EP 2.2.3.
FAQ
Does the ZD-3A support GLP-compliant data integrity requirements?
Yes—when used with enabled timestamping, non-erasable local storage, and CSV export, it supports ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate). Full 21 CFR Part 11 compliance requires supplemental access controls and electronic signature modules, available via Yoke’s validated LabSuite Pro add-on.
Can I connect third-party electrodes or burettes?
The ZD-3A accepts any BNC-terminated pH or redox electrode and supports standard 10 mL or 25 mL glass burettes with compatible solenoid valve adapters. Custom electrode configurations require verification of output impedance and signal range compatibility.
What maintenance intervals are recommended for long-term accuracy?
Electrode calibration is advised before each analytical session; solenoid valve performance should be verified monthly using gravimetric dispensing checks. Annual verification of mV linearity and temperature sensor drift against NIST-traceable references is recommended for regulated environments.
Is method transfer possible between ZD-3A units?
Yes—method parameters (endpoint thresholds, increment volumes, delay times, temperature compensation coefficients) are fully exportable/importable via USB, ensuring consistent operation across multiple instruments in multi-site laboratories.
Does the instrument support kinetic titration or derivative endpoint detection?
No—the ZD-3A implements fixed-endpoint and slope-threshold detection only. For first-derivative (dE/dV) or second-derivative (d²E/dV²) equivalence point calculation, consider the Yoke ZD-4A or ZD-5A series with enhanced algorithm firmware.
