OHAUS AP30CD Portable Chlorine Dioxide Colorimeter

Overview

The OHAUS AP30CD Portable Chlorine Dioxide Colorimeter is a field-deployable photometric analyzer engineered for rapid, on-site quantification of chlorine dioxide (ClO₂) in aqueous matrices. It operates on fixed-wavelength absorption photometry—specifically optimized for the characteristic absorbance peak of ClO₂–indigo carmine or DPD-based reaction products—ensuring selectivity and minimal interferences from free chlorine, chloramines, or oxidized manganese. Unlike broad-spectrum spectrophotometers, the AP30CD employs discrete, temperature-stabilized LEDs at pre-calibrated wavelengths (e.g., 530 nm or 580 nm, depending on reagent chemistry), eliminating spectral drift and reducing calibration dependency. Its compact form factor (142 × 78 × 42 mm), low power draw (2,000 tests per set of AAA cells) make it suitable for unattended operation in remote distribution networks, cooling towers, or emergency response scenarios where grid power is unavailable.

Key Features

• Optimized optical path with precision-aligned LED source, high-transmittance cuvette holder, and silicon photodiode detector—designed to minimize stray light and deliver repeatability ≤±2% RSD across 0.01–5.00 mg/L ClO₂ range.
• Touch-sensitive control interface with haptic feedback—enabling glove-compatible operation in industrial or outdoor environments without compromising tactile accuracy.
• Low reagent consumption: ≤0.5 mL sample volume and ≤1.0 mL reagent per test, compatible with standardized EPA Method 334.0 and ISO 7393-2 derivatized protocols.
• Integrated data management: 5,000 timestamped records stored with operator ID, location tag (manual entry), and measurement units; no internal clock drift due to RTC (real-time clock) with battery backup.
• IP67-rated enclosure—validated per IEC 60529—protecting against immersion up to 1 m for 30 minutes and total dust ingress, including sealed micro-USB port and silicone-sealed keypad.

Sample Compatibility & Compliance

The AP30CD is validated for use with clarified, low-turbidity water samples (NTU < 5) across municipal drinking water, secondary effluent, recirculating cooling systems, and treated swimming pool water. It complies with functional requirements outlined in ASTM D1253 (Standard Test Method for Residual Chlorine in Water) when adapted for ClO₂-specific reagents. While not a GLP-certified instrument, its audit-ready data export supports 21 CFR Part 11–aligned workflows when paired with OHAUS AquaLog™ desktop software (v2.1+), enabling electronic signature capture, user access controls, and immutable record archiving. All ClO₂ test kits supplied meet ISO 17025-accredited manufacturing standards and include lot-specific calibration certificates traceable to NIST SRM 2801.

Software & Data Management

Data transfer occurs via micro-USB connection to Windows/macOS systems using OHAUS AquaLog™ PC Suite—a validated application supporting CSV/Excel export, trend graphing (time-series ClO₂ decay curves), and customizable report templates compliant with ISO/IEC 17025 documentation clauses. The software enforces role-based permissions (Admin, Technician, Viewer), maintains full audit trails (including parameter changes, calibration events, and data deletion logs), and generates PDF reports with embedded digital signatures. No cloud upload or telemetry is enabled by default; all data remains under end-user control unless explicitly configured.

Applications

• Real-time verification of ClO₂ dosing efficacy in municipal disinfection contact tanks and point-of-use treatment units.
• Monitoring residual oxidant stability in closed-loop cooling water systems to prevent biofilm regrowth and microbiologically influenced corrosion (MIC).
• Validation of ClO₂ generation efficiency in electrochemical or sodium chlorite–acid activation systems.
• Regulatory compliance sampling for NSF/ANSI Standard 60-certified treatment chemicals in potable water applications.
• Rapid assessment of ClO₂ decay kinetics during UV exposure or in presence of organic precursors (e.g., humic substances) in pilot-scale studies.

FAQ

Is the AP30CD compliant with EPA or WHO chlorine dioxide testing guidelines?
Yes—the instrument’s optical configuration and recommended reagent protocols align with EPA Method 334.0 (for DPD-based ClO₂ determination) and WHO Guidelines for Drinking-water Quality (4th ed., Annex 2), provided users follow specified sample handling, pH adjustment, and interference mitigation steps.
Can the AP30CD measure other disinfectants such as free chlorine or chloramines?
No—the AP30CD is factory-configured exclusively for chlorine dioxide. It does not support multi-parameter firmware upgrades or wavelength reconfiguration. For broader disinfectant profiling, OHAUS recommends the AQ4000 series benchtop photometer.
What is the calibration frequency requirement under routine field use?
OHAUS recommends daily verification using a fresh NIST-traceable standard (0.50 mg/L ClO₂) prior to first measurement; full two-point calibration (zero + span) every 72 hours or after reagent lot change.
Does the device support external GPS tagging of measurements?
No—GPS functionality is not integrated. Location metadata must be manually entered during sample logging or appended externally via spreadsheet linkage post-export.
Are replacement cuvettes and reagent kits supplied with NIST-traceable certificates?
Yes—all consumables sold under OHAUS part numbers AP30-CLD-KIT (reagents) and AP30-CUV-SET (quartz cuvettes) include individual CoA documents with uncertainty budgets and traceability statements to NIST SRM 2801 or equivalent national metrology institute references.