Hach DR900 Multi-Parameter Portable Colorimeter

Overview

The Hach DR900 Multi-Parameter Portable Colorimeter is a field-deployable spectrophotometric analyzer engineered for precision quantitative analysis of water quality parameters in demanding environmental and industrial settings. It operates on the principle of Beer-Lambert law-based absorbance measurement, where analyte-specific reagents generate chromophores whose optical density at defined wavelengths correlates linearly with concentration. The instrument employs fixed-wavelength LED light sources (typically 420 nm, 520 nm, 580 nm, 610 nm, and 650 nm, depending on method configuration) and a silicon photodiode detector to deliver stable, repeatable photometric readings. Its ruggedized architecture—including shock-absorbing elastomer overmolding and sealed optical path—ensures metrological integrity under vibration, temperature fluctuation, and transient humidity exposure. Unlike benchtop spectrophotometers, the DR900 eliminates wavelength scanning complexity while maintaining traceable accuracy through NIST-traceable factory calibration and user-accessible zero/standard adjustment routines.

Key Features

• IP67-rated enclosure certified for full dust ingress protection and immersion resistance up to 1 m for 30 minutes—validated per IEC 60529.
• Dual-mode calibration support: blank correction (zero adjustment) and standard calibration (span adjustment) to compensate for batch-to-batch reagent variability and cuvette optical path differences.
• Three simultaneous readout modes: concentration (mg/L, ppm, µg/L), percent transmittance (%T), and absorbance (AU)—each selectable per method without recalibration.
• Ergonomic handheld form factor with textured grip and recessed keypad, optimized for single-handed operation wearing gloves in field conditions.
• Backlit monochrome LCD with high-contrast icons and contextual soft-keys, readable under direct sunlight (tested per ISO 9241-305 glare resistance criteria) and low-light environments.
• Onboard memory stores 500 measurement records with GLP-compliant metadata: timestamp (RTC), operator ID, selected method number, calibration status flag, and cuvette ID (if encoded).

Sample Compatibility & Compliance

The DR900 accommodates standard 13-mm round glass or plastic cuvettes (including Hach’s matched 13-mm square cuvettes for select methods) and supports both liquid-phase colorimetric assays and solid-phase test strip quantification (e.g., chlorine dip strips). It complies with ASTM D1253 (residual chlorine), ASTM D1292 (chloride), ASTM D5176 (COD by closed-reflux colorimetry), and ISO 7888 (turbidity by nephelometry—when used with optional turbidity adapter). All preprogrammed methods align with EPA-approved analytical techniques for drinking water (40 CFR Part 141), wastewater (40 CFR Part 136), and industrial effluent monitoring. Instrument firmware adheres to IEC 61000-4 electromagnetic compatibility standards and UL 61010-1 safety requirements for portable laboratory equipment.

Software & Data Management

Data export occurs via USB 2.0 interface to Windows-based Hach Lab Software (v5.0+), which provides audit-trail functionality compliant with FDA 21 CFR Part 11 requirements—including electronic signatures, change history logging, and role-based access control. Exported files (.csv or .hach format) retain full GLP metadata and are structured for direct import into LIMS platforms (e.g., Thermo Fisher SampleManager, LabVantage). Firmware updates are delivered via Hach’s secure portal and validated using SHA-256 checksums to ensure code integrity. No cloud connectivity or remote telemetry is embedded—data sovereignty remains fully under end-user control.

Applications

The DR900 serves as a primary field verification tool across regulated and non-regulated water matrices: routine chlorine residual monitoring in municipal distribution systems (per AWWA C651); COD and ammonia-nitrogen screening in activated sludge plants; TOC estimation in pharmaceutical purified water loops (USP ); nutrient profiling (phosphate, nitrate) in agricultural runoff; boiler feedwater hardness testing; and educational laboratory instruction in environmental chemistry curricula. Its method flexibility enables rapid transition between regulatory compliance checks (e.g., drinking water total coliform presence/absence confirmation via chlorine decay kinetics) and process optimization tasks (e.g., coagulant dosing validation via turbidity response curves).

FAQ

Does the DR900 require annual factory recalibration?
No—routine user-performed blank and standard adjustments satisfy traceability requirements. Hach recommends annual performance verification using NIST-traceable reference standards; full recalibration is only necessary if optical drift exceeds ±0.005 AU at 610 nm.
Can custom methods be transferred between DR900 units?
Yes—user-defined methods (up to 10) are stored in non-volatile memory and can be exported/imported via USB using Hach Lab Software.
Is the instrument suitable for seawater analysis?
Yes, provided salinity-corrected methods are applied (e.g., chloride determination using mercury-free thiocyanate chemistry); salt deposition on optics requires post-use rinsing with deionized water.
What cuvette types are supported?
13-mm round glass (Hach catalog #2377000) or polystyrene cuvettes (Hach #2377100); square 13-mm cuvettes (Hach #2439400) for turbidity-enabled configurations.
How is battery life managed during extended field deployment?
Four AA alkaline batteries provide ≥2,000 measurements per set; auto-power-off after 10 minutes of inactivity extends service life. Optional rechargeable NiMH battery pack (Hach #2851500) is available.