Leici DDS-307A Benchtop Conductivity Meter

Overview

The Leici DDS-307A Benchtop Conductivity Meter is a precision-engineered electrochemical analyzer designed for routine and quality-critical conductivity, total dissolved solids (TDS), and temperature measurements in regulated laboratory environments. Based on the principle of two-electrode AC conductometric measurement at selectable frequencies (typically 1 kHz or 10 kHz), the instrument determines solution conductivity by applying a low-amplitude alternating current across a standardized cell and measuring the resulting voltage drop. Conductivity values are automatically converted to TDS using user-selectable conversion factors (default: 0.50–0.70, configurable), and all readings are referenced to 25 °C via built-in temperature compensation algorithms compliant with ISO 7888 and ASTM D1125. Its Class 1.0 accuracy rating—defined under GB/T 11018–2021—ensures traceable performance suitable for QC/QA workflows in water treatment, pharmaceutical excipient testing, academic research, and food & beverage process validation.

Key Features

• Benchtop form factor with compact footprint (242 × 195 × 68 mm) and lightweight design (0.9 kg) for space-constrained lab benches
• High-contrast LCD display with backlight and intuitive membrane keypad navigation
• IP54-rated enclosure providing protection against dust ingress and water splashes during daily operation
• Auto-endpoint detection algorithm that identifies measurement stability per IUPAC-recommended criteria, reducing operator dependency
• Intelligent electrode recognition and auto-frequency switching to maintain optimal signal-to-noise ratio across the full 0.00 µS/cm–200.0 mS/cm range when used with a standard 1.0 cm⁻¹ cell
• Dual-compensation support: automatic temperature compensation (ATC) using integrated Pt1000 sensor, plus manual temperature override (MTT) for method-specific protocols
• Factory-programmed recognition of four Chinese national conductivity standards (GB solutions), enabling rapid single-point calibration without manual entry
• Configurable data logging: stores up to 50 complete measurement sets—including conductivity, TDS, temperature, date/time stamp, and calibration status—for audit-ready traceability

Sample Compatibility & Compliance

The DDS-307A is validated for aqueous samples within pH 2–12 and non-corrosive ionic matrices. It accommodates standard DIN/ISO-compatible 1.0 cm⁻¹ two-electrode conductivity cells (e.g., Leici DJS-1C) and supports optional temperature probes with 3-wire Pt1000 configuration. The instrument meets metrological requirements outlined in JJG 376–2007 (Verification Regulation for Conductivity Meters) and conforms to general-purpose laboratory instrument provisions under Good Laboratory Practice (GLP). While not certified for FDA 21 CFR Part 11 compliance out-of-the-box, its immutable timestamped data storage, absence of editable fields, and factory-resettable calibration history support retrospective audit readiness in regulated settings where electronic records are retained as printed reports or exported CSV files.

Software & Data Management

Data management is implemented via onboard memory only—no proprietary software or USB connectivity is included. Each stored record contains conductivity (µS/cm or mS/cm), calculated TDS (mg/L or g/L), measured temperature (°C), and system timestamp (YYYY-MM-DD HH:MM). Records can be reviewed, navigated, and selectively deleted using front-panel controls. Export functionality is not embedded; however, users may manually transcribe data or integrate the meter into custom LIMS workflows via RS-232 (optional accessory interface, not standard). All calibration events—including date, standard used, slope, and offset—are logged and retrievable alongside measurement data.

Applications

• Drinking water and wastewater effluent monitoring per GB 5749–2022 and HJ/T 342–2007
• Pharmaceutical water system qualification (Purified Water, Water for Injection) per ChP and USP
• Electrolyte concentration verification in battery electrolyte R&D and quality control
• TDS estimation in hydroponic nutrient solutions and aquaculture systems
• Raw material screening for salts, acids, and bases in fine chemical synthesis
• Academic teaching labs for fundamental electrochemistry experiments including Kohlrausch’s law verification and ion mobility studies

FAQ

What conductivity cell constant is required for full-range coverage?
A 1.0 cm⁻¹ two-electrode cell (e.g., Leici DJS-1C) is recommended and fully supported with auto-frequency switching.
Does the instrument support multi-point calibration?
No—it implements single-point calibration with auto-recognition of four GB-standard solutions; multi-point calibration is not available in firmware.
Can measurement data be exported electronically?
Not natively; data must be manually recorded or captured via optional RS-232 interface with third-party terminal software.
Is the temperature sensor integrated or external?
The Pt1000 temperature sensor is integrated into the standard conductivity electrode assembly; no separate probe is needed.
What is the warm-up time before first measurement?
Less than 60 seconds after power-on; stable readings are achieved within 2–3 minutes under ambient conditions (23 ± 2 °C).