Guance GCSTD-F Liquid Dielectric Constant Meter
| Brand | Guance Instruments |
|---|---|
| Origin | Beijing, China |
| Manufacturer Type | Authorized Distributor |
| Product Origin | Domestic (China) |
| Model | GCSTD-F |
| Price | USD 1,280 (FOB Beijing) |
Overview
The Guance GCSTD-F Liquid Dielectric Constant Meter is a precision benchtop instrument engineered for the quantitative determination of relative permittivity (εr) and conductivity (σ) of homogeneous liquid samples across a fixed-frequency AC excitation regime. It operates on the principle of guarded coaxial cylindrical capacitance measurement—leveraging a well-defined electrode geometry to establish a stable, reproducible electric field within the sample volume. The system applies a low-voltage sinusoidal signal (typically 1 kHz or user-selectable single frequency per configuration) and measures the resulting complex impedance (Z* = Z′ + jZ″), from which εr and loss tangent (tan δ) are derived using calibrated geometric constants and standard dielectric mixing models. This method conforms to fundamental electrostatic theory described in IEC 60250 and ASTM D150-21, making it suitable for quality control, formulation development, and academic research where repeatable, geometry-referenced permittivity data are required.
Key Features
- Precision-machined coaxial cylindrical electrode assembly fabricated entirely from 316 stainless steel—ensuring long-term dimensional stability, corrosion resistance, and minimal surface charge retention.
- Fixed-gap geometry maintained by six non-conductive nylon spacers; gap tolerance ≤ ±2 µm, enabling traceable calibration against NIST-traceable reference liquids (e.g., deionized water, methanol, cyclohexane).
- Open-structure electrode design allows full visual access and rapid, residue-free cleaning—critical for sequential testing of solvents, hydrocarbons, polar organics, and ionic solutions.
- No disassembly required during routine maintenance; cleaning validated via ultrasonic immersion in ethanol, acetone, or solvent-matched media—compatible with PTFE, nylon, and stainless-steel components.
- Integrated temperature stabilization port (optional external circulator interface) supports controlled measurements at 20–40 °C, aligning with ISO 27327-1 for liquid dielectric characterization under thermal equilibrium conditions.
Sample Compatibility & Compliance
The GCSTD-F accommodates transparent, low-viscosity ( 10 mS/cm), or viscous polymers that cannot fully wet the electrode surface. All measurements comply with the geometric constraints defined in IEC 60250 Annex B for coaxial cylindrical cells. While the instrument itself does not carry CE or UKCA marking, its measurement methodology and documentation support GLP-compliant lab workflows, including audit-ready calibration logs, operator ID tagging, and raw impedance export for third-party validation.
Software & Data Management
Data acquisition is performed via RS-232 or USB-to-serial interface using Guance’s GCSTD Control Suite (v3.2+), a Windows-based application supporting real-time impedance plotting, εr/σ dual-parameter calculation, and CSV/TXT export. The software enforces user-defined pass/fail thresholds, stores measurement metadata (date/time, operator, ambient T/RH, sample ID), and generates PDF reports compliant with internal QA templates. Though not 21 CFR Part 11 certified out-of-the-box, the system architecture permits integration with LIMS platforms via standardized ASCII output and supports electronic signature add-ons for regulated environments upon site-specific validation.
Applications
- Quality assurance of industrial solvents and petrochemical feedstocks (e.g., monitoring moisture ingress in transformer oil via εr drift).
- R&D of battery electrolytes—correlating permittivity trends with Li-salt dissociation efficiency and SEI formation propensity.
- Pharmaceutical excipient screening—differentiating polarity profiles of co-solvents used in parenteral formulations.
- Academic studies of molecular dipole alignment under static fields, including temperature-dependent Debye relaxation analysis.
- Environmental labs assessing dielectric fingerprints of contaminated groundwater plumes containing chlorinated hydrocarbons or PAHs.
FAQ
Can the electrode be disassembled for cleaning?
No. Disassembly compromises the calibrated inter-electrode gap and invalidates all factory calibration. Only ultrasonic immersion in appropriate solvents is permitted.
What is the minimum sample volume required?
25 mL is recommended to ensure full immersion of the active electrode length (50 mm) while maintaining meniscus stability.
Is temperature control built-in?
No. The unit includes a threaded port for connection to an external recirculating chiller or thermostat bath (not supplied).
Does the instrument support multi-frequency measurement?
No. The GCSTD-F operates at a single factory-set frequency (1 kHz standard); variable-frequency capability requires the GCSTD-VF series.
How often must calibration be verified?
We recommend verification with certified reference liquids every 30 days or before each critical batch test, following ASTM D150 Section 8.3 procedures.
