Leici DDBJ-350 Portable Conductivity Meter

Overview

The Leici DDBJ-350 Portable Conductivity Meter is a precision-engineered electrochemical instrument designed for reliable, field-deployable, and laboratory-grade measurement of conductivity, resistivity, total dissolved solids (TDS), salinity, and temperature in aqueous solutions. Based on four-electrode or two-electrode AC conductometric principles—depending on selected cell constant—the DDBJ-350 delivers high reproducibility across an exceptionally wide dynamic range (0.000 µS/cm to 500 mS/cm). Its architecture integrates digital signal processing with adaptive frequency switching, enabling accurate low-conductivity measurements (e.g., ultrapure water) and high-salinity samples without manual range selection. The device complies with Chinese national standards (GB/T 6682, GB/T 11025) for water quality analysis and meets fundamental metrological requirements for Class 1.0 instruments per JJG 376–2007, ensuring traceable performance in regulated environments.

Key Features

• High-contrast LCD display with adjustable backlight for optimal readability under variable lighting conditions—including outdoor or low-light lab settings.
• Multi-parameter simultaneous measurement: conductivity, resistivity, TDS (calculated using NaCl or user-defined conversion factors), salinity (based on Practical Salinity Scale PSS-78), and temperature—with automatic unit switching between °C and °F.
• Intelligent endpoint detection with configurable read modes: auto-hold, timed reading, interval logging, and manual capture—enabling consistent data acquisition during kinetic studies or routine QC checks.
• IP65-rated enclosure ensures dust-tight operation and protection against low-pressure water jets, supporting robust use in humid laboratories, cleanrooms, or semi-field applications such as wastewater sampling stations.
• Auto-recognition of four standardized GB conductivity reference solutions (e.g., 1413 µS/cm, 12.88 mS/cm) simplifies calibration validation and reduces operator error during multi-point electrode standardization.
• Three temperature compensation algorithms: non-compensated (raw reading), linear (with selectable reference at 20 °C or 25 °C), and specialized pure-water mode that applies non-linear correction for deionized and distilled water below 10 µS/cm.
• Integrated rechargeable lithium-ion battery (up to 100 hours typical runtime) with real-time charge-state indication, low-voltage warning, and dual charging options—via included AC adapter (100–240 V AC input) or universal 5 V USB power source.

Sample Compatibility & Compliance

The DDBJ-350 accommodates diverse sample matrices—from ultrapure water (≥18.2 MΩ·cm) to concentrated brines—through interchangeable conductivity cells (K = 0.01, 0.1, or 1.0 cm⁻¹). Its auto-frequency switching logic dynamically selects optimal excitation frequencies (typically 30 Hz to 1 kHz) to minimize polarization effects and capacitive interference, especially critical for low-conductivity or high-viscosity samples. The instrument satisfies core elements of Good Laboratory Practice (GLP) compliance, including timestamped data logging, user ID entry (optional via software), audit-trail-capable storage (500 entries per parameter), and factory-reset security. While not certified to FDA 21 CFR Part 11 out-of-the-box, its structured data export (CSV via USB or RS-232) supports integration into validated LIMS or ELN systems where electronic records are subject to regulatory review (e.g., ISO/IEC 17025-accredited labs).

Software & Data Management

Data transfer is facilitated through native USB connectivity and optional RS-232 serial interface. Leici’s proprietary PC communication software enables bidirectional synchronization: downloading stored measurements (including full metadata—date/time, temperature, cell constant, calibration history) and uploading configuration profiles (e.g., compensation type, TDS factor, display units). All datasets include embedded instrument ID and firmware version for unambiguous traceability. Measurement reports can be exported in CSV or PDF format and printed directly to compatible RS-232 thermal printers with customizable layout templates—supporting QC documentation workflows requiring hard-copy archiving. Firmware updates are delivered via USB stick, allowing functional enhancements and protocol revisions without hardware modification.

Applications

• Environmental monitoring: surface water, groundwater, and effluent conductivity profiling per EPA Method 120.1 or ISO 7888.
• Pharmaceutical water systems: USP WFI and Purified Water conductivity verification (Stage 1–3 testing per USP ).
• Food & beverage QA/QC: brine concentration control, syrup dilution monitoring, and cleaning-in-place (CIP) rinse water verification.
• Academic research: electrolyte characterization, membrane permeability studies, and corrosion inhibitor evaluation in simulated cooling water circuits.
• Education: undergraduate electrochemistry labs emphasizing conductometric titration, Kohlrausch’s law, and ion mobility fundamentals.

FAQ

What cell constants are supported?
The DDBJ-350 supports K = 0.01, 0.1, and 1.0 cm⁻¹ electrodes. Automatic cell constant recognition occurs upon connection of compatible Leici smart electrodes.
Does the meter support GLP-compliant data export?
Yes—each stored record includes date/time stamp, measured values, temperature, cell constant, calibration status, and operator ID (if entered). Exported CSV files retain all metadata for audit-ready reporting.
Can it measure conductivity in non-aqueous solvents?
No. The DDBJ-350 is calibrated and validated exclusively for aqueous solutions. Conductivity measurements in organic solvents require specialized instrumentation with solvent-specific cell design and temperature control.
Is temperature compensation mandatory?
No. Users may select “no compensation” mode for raw conductivity output, though temperature-corrected values are recommended for comparative analysis across varying ambient conditions.
How often should calibration be performed?
Calibration frequency depends on usage intensity and regulatory requirements. Daily verification with a single standard is advised for QC-critical applications; full 2–3 point calibration is recommended after electrode cleaning, replacement, or when drift exceeds ±1% FS.