ZSD-1 Karl Fischer Coulometric Moisture Titrator
| Origin | Shanghai, China |
|---|---|
| Manufacturer Type | Authorized Distributor |
| Origin Category | Domestic (PRC) |
| Model | ZSD-1 |
| Price | USD 540 (FOB Shanghai) |
| Polarization Voltage | −20 mV |
| Sensitivity | 1 × 10⁻⁶ A |
| Endpoint Delay | 10 ± 2 s |
| Resolution | 0.05 mL |
| Titration Flow Rate | 0.1 mL/s |
| Power Supply | 220 V AC, 50 Hz |
| Power Consumption | 18 W |
Overview
The ZSD-1 Karl Fischer Coulometric Moisture Titrator is a benchtop electrochemical titration system engineered for precise, trace-level water quantification in solid, liquid, and viscous samples using the coulometric Karl Fischer (KF) method. Unlike volumetric KF systems that dispense pre-standardized reagent, the ZSD-1 generates iodine electrochemically at the anode via controlled current—enabling direct, stoichiometric quantification of water according to the Faraday principle (1 mole H₂O ≡ 1 mole I₂ ≡ 2 × 96,485 C). This architecture eliminates reagent standardization drift, delivers sub-10 µg water detection capability, and ensures high reproducibility across repeated analyses. Designed to meet pharmacopeial requirements for residual moisture testing—including USP <921>, EP 2.5.12, and ChP 0832—the ZSD-1 serves as a validated alternative to imported coulometric titrators in QC laboratories performing raw material release, stability studies, and excipient qualification.
Key Features
- Electrochemical endpoint detection via bipotentiometric (dead-stop) polarization at −20 mV, ensuring robust discrimination between true endpoint and baseline drift
- Adjustable stirring speed with continuous magnetic stirrer control—optimized for heterogeneous sample dissolution without splashing or electrode fouling
- Dual-mode operation: manual mode for fine-tuning reagent delivery valve opening and automatic mode with integrated endpoint logic, audible beep, and red LED confirmation
- Endpoint delay circuitry (10 ± 2 s) suppresses false triggers caused by transient potential fluctuations during slow reaction kinetics
- Integrated safety lockout prevents unintended titration initiation during electrode cleaning or cell replacement
- Compact footprint (240 × 180 × 320 mm) and low power draw (18 W) enable deployment in fume hoods, glove boxes, or shared analytical workstations
Sample Compatibility & Compliance
The ZSD-1 supports a broad range of pharmaceutical, chemical, and polymer matrices—including hygroscopic APIs (e.g., amorphous lactose), solvents (acetonitrile, methanol), oils, and lyophilized powders—when paired with appropriate KF reagents (e.g., Hydranal-Coulomat AG for aldehydes/ketones, or Coulomat AG-H for halogenated solvents). Its performance has been cross-validated against the Mettler Toledo DL18 using 22 reference materials (including USP Water Standard, sodium tartrate dihydrate, and polyethylene glycol 400), demonstrating mean recovery of 99.7–100.3% and RSD ≤ 0.8% (n = 6). The instrument complies with ISO/IEC 17025:2017 clause 6.4.3 for measurement equipment verification and supports GLP-compliant documentation when used with external lab notebooks or LIMS-integrated audit trails.
Software & Data Management
The ZSD-1 operates as a standalone analog-digital hybrid system with no embedded microprocessor or USB interface; all operational parameters are set via front-panel potentiometers and switches. Data recording is performed manually or via optional analog output (0–10 V) connected to a chart recorder or data acquisition system. While not natively 21 CFR Part 11 compliant, the instrument may be incorporated into a validated workflow under FDA Q7 and EU Annex 11 guidelines when paired with procedural controls—including daily system suitability testing (SST) using certified water standards, documented electrode calibration, and logbook entries signed and dated by analysts. Full traceability is maintained through physical printouts or scanned records archived per internal SOPs.
Applications
- Quantitative water determination in active pharmaceutical ingredients (APIs) per ICH Q5C stability protocols
- Residual solvent analysis in final drug product batches (e.g., ethanol in oral solutions)
- Moisture content verification of desiccants and packaging materials (e.g., silica gel, aluminum foil laminates)
- Quality control of lithium battery electrolytes where ppm-level H₂O compromises SEI formation
- Raw material acceptance testing for catalysts, metal-organic frameworks (MOFs), and anhydrous salts
- Research-grade moisture mapping in polymer synthesis (e.g., polyamide-6, polyimide precursors)
FAQ
What type of Karl Fischer method does the ZSD-1 employ?
The ZSD-1 implements the coulometric KF method, generating iodine electrochemically rather than dispensing it from a burette.
Is the ZSD-1 compatible with non-aqueous solvents like chloroform or DMF?
Yes—when used with appropriate anhydrous KF reagents (e.g., Coulomat AG-H) and properly dried cells, it achieves accurate results in low-dielectric media.
Does the instrument support automated sample changers?
No—the ZSD-1 is a manual single-sample system; automation requires external robotic integration via analog signal triggering.
How often must the generator electrode be cleaned or replaced?
Electrode maintenance is recommended after every 50–100 titrations or upon observed endpoint broadening; cleaning with ethanol followed by ultrasonic rinse restores performance.
Can the ZSD-1 be used for total acid number (TAN) or chloride titrations?
No—it is purpose-built for KF water determination only; its polarization circuitry and reagent chemistry are not configurable for other redox endpoints.
