Leici DGB-421F Portable Platinum-Cobalt Colorimeter

Overview

The Leici DGB-421F Portable Platinum-Cobalt Colorimeter is a field-deployable, laboratory-grade instrument engineered for precise, traceable quantification of apparent color in water and wastewater samples according to the platinum-cobalt (Pt-Co) scale. It operates on the principle of single-wavelength photometric absorbance measurement at 365 nm—a spectral region where Pt-Co standard solutions exhibit maximal and stable absorption—ensuring high selectivity and minimal interference from turbidity or organic chromophores outside this band. Designed for compliance with national and international drinking water standards—including GB/T 5750.4–2023, ISO 7887:2011, ASTM D1209, and USP —the DGB-421F delivers metrologically sound results across two dynamic ranges: 0.0–99.9 PCU (Hazen units) for low-color potable waters and 100–500 PCU for moderately colored industrial effluents or surface waters. Its optical architecture features a temperature-stabilized 365 nm LED light source with >10,000-hour operational lifetime, eliminating lamp drift and reducing recalibration frequency.

Key Features

• High-contrast 3.5-inch color TFT-LCD display with adjustable backlight and auto-dimming function for indoor and outdoor readability
• Dual-range measurement capability (0.0–99.9 and 100–500 PCU) with automatic range switching and linear response across full span
• Integrated unit conversion: simultaneous display and storage in PCU, Hazen, and mg Pt·L⁻¹—fully aligned with Pt-Co reference standards
• 25 mm pathlength cuvette geometry compliant with GB/T 5750.4 and ASTM D1209 specifications
• GLP-compliant data management: each stored record includes user ID, sample ID, date/time stamp, calibration ID, and battery level at time of measurement
• IP65-rated enclosure for dust-tight operation and resistance to low-pressure water jets—suitable for field use in humid or splash-prone environments
• Rechargeable lithium-ion battery (≥12 hours continuous operation) with real-time charge-level indicator and charging-status LED
• Auto-power-off after 10 minutes of inactivity; manual override available via keypress

Sample Compatibility & Compliance

The DGB-421F accepts clear to slightly turbid aqueous samples without filtration when turbidity remains below 5 NTU—consistent with GB/T 5750.4 guidance for color measurement. For samples exceeding this threshold, optional pre-filtration through 0.45 µm membrane filters is recommended prior to analysis. The instrument is validated for use with certified Pt-Co standard solutions (e.g., NIST-traceable 500 PCU stock) prepared per GB/T 5750.4 Annex A. Calibration supports 1–5 point non-linear curve fitting, enabling accurate quantification across extended ranges or for matrix-matched standards. All calibration events—including factory defaults, user-defined curves, and dilution-factor corrections—are retained in non-volatile memory with immutable timestamps. Instrument performance verification meets ISO/IEC 17025 internal quality control requirements for environmental testing laboratories.

Software & Data Management

Data export is facilitated via USB 2.0 interface using Leici’s proprietary DGB-Link communication software (Windows 10/11 compatible), supporting CSV and XLSX formats with embedded metadata fields. RS-232 serial output enables direct printing to industry-standard thermal or dot-matrix printers (e.g., Epson TM-T20II). The device maintains an audit trail of all critical operations—including power-on cycles, calibration changes, and data deletions—satisfying FDA 21 CFR Part 11 electronic record requirements when used within validated workflows. Stored datasets include full traceability: operator credentials, sample identifiers, instrument serial number, firmware version, and environmental conditions (battery voltage at measurement time).

Applications

• Drinking water treatment plants: routine monitoring of finished water color against WHO and GB 5749 limits (≤15 PCU)
• Environmental field surveys: rapid assessment of surface water color anomalies indicating algal blooms, tannin leaching, or industrial discharge
• Pharmaceutical water systems: USP compliance verification for Purified Water and Water for Injection
• Food & beverage QC labs: color consistency checks in process water, syrup diluents, and rinse solutions
• Educational laboratories: hands-on instruction in photometric principles, standard curve development, and regulatory method implementation

FAQ

What standards does the DGB-421F comply with for color measurement?
It conforms to GB/T 5750.4–2023, ISO 7887:2011, ASTM D1209, and USP , with optical design optimized for Pt-Co reference methodology.
Can the instrument measure samples with high turbidity?
Turbidity should be ≤5 NTU per GB/T 5750.4; samples exceeding this require 0.45 µm filtration prior to analysis to avoid scattering artifacts.
How is calibration traceability maintained?
Calibration uses NIST-traceable Pt-Co standards; all curve parameters, dates, and operator IDs are stored with cryptographic integrity in onboard flash memory.
Is the USB data export compliant with 21 CFR Part 11?
Yes—when deployed with validated DGB-Link software and documented access controls, it satisfies electronic signature and audit trail requirements for regulated environments.
What is the expected service life of the 365 nm LED source?
Rated for ≥10,000 hours of continuous operation under nominal conditions, with negligible spectral shift over its lifetime.