Zhuochi AOX-WK-S Microcoulometric Halogen Analyzer for Water Quality Analysis
| Brand | Zhuochi |
|---|---|
| Model | AOX-WK-S |
| Application | Adsorbable Organic Halogens (AOX) in Water |
| Measurement Principle | Combustion-Microcoulometric Titration |
| Temperature Range | 500–1000 °C (±1% ±5 °C) |
| Accuracy | <5% |
| Repeatability | <5% |
| Detection Limit | 0.1 µg/L |
| Compliance | HJ 1214–2021 (China EPA Standard) |
| Origin | Zhejiang, China |
| Supplier Type | Authorized Distributor |
Overview
The Zhuochi AOX-WK-S Microcoulometric Halogen Analyzer is a dedicated analytical system engineered for the precise quantification of adsorbable organic halogens (AOX) in aqueous environmental samples, in full accordance with the Chinese national standard HJ 1214–2021, “Determination of Adsorbable Organic Halogens (AOX) in Water—Microcoulometric Method.” The instrument operates on the combustion-microcoulometric titration principle: water samples are first pre-concentrated via activated carbon adsorption, followed by thermal desorption and high-temperature catalytic combustion (500–1000 °C) to convert all organically bound chlorine, bromine, and iodine into hydrogen halides (HX). These gaseous halides are swept through an electrolytic cell where quantitative electrochemical titration occurs—measuring the charge required to regenerate silver ions at the working electrode. The resulting coulombic signal is directly proportional to total halogen mass, enabling trace-level AOX determination with metrological traceability.
Key Features
- Integrated dual-zone programmable combustion furnace with independent gas-flow temperature control—ensuring stable thermal decomposition across the full 500–1000 °C range (±1% ±5 °C tolerance)
- Dedicated quartz combustion tube optimized for complete mineralization of refractory organic halogen compounds without memory effect or carryover
- Automated sample introduction and ash removal mechanism minimizing operator intervention and cross-contamination risk
- High-sensitivity microcoulometric detection cell with Ag/AgNO3 electrolyte system, calibrated per ASTM D5808 and ISO 9562 guidelines
- Onboard column adsorption module compliant with HJ 1214–2021 requirements for activated carbon pre-concentration (including flow rate control, breakthrough validation, and desorption efficiency verification)
- Rugged industrial-grade architecture designed for continuous operation in municipal wastewater labs, environmental monitoring stations, and third-party testing facilities
Sample Compatibility & Compliance
The AOX-WK-S supports analysis of surface water, groundwater, drinking water, wastewater effluents, and leachates—with matrix-specific validation protocols included. All components meet material compatibility requirements for halogen-rich samples (e.g., PTFE-lined gas pathways, quartz and high-purity alumina furnace linings). System performance is validated against certified reference materials (CRMs) traceable to NIM (National Institute of Metrology, China) and verified per HJ 1214–2021 precision and recovery criteria. While primarily aligned with Chinese regulatory frameworks, the underlying combustion-coulometric methodology is consistent with internationally recognized approaches including ISO 9562 and EPA Method 1650 (withdrawn but technically referenced).
Software & Data Management
The analyzer is controlled via embedded firmware with USB interface and compatible Windows-based acquisition software. Software functions include real-time coulombic current monitoring, automatic baseline correction, peak integration with configurable retention windows, calibration curve generation (linear or quadratic), and audit-trail-enabled data logging. All measurement records—including method parameters, raw signals, calibration history, and user annotations—are timestamped and stored in encrypted binary format. Data export supports CSV and PDF report generation suitable for internal QA review or regulatory submission. The system supports GLP-compliant workflows through electronic signature prompts, user access levels (admin/operator), and immutable log files meeting basic 21 CFR Part 11 readiness (though not formally validated for FDA-regulated environments).
Applications
- Regulatory compliance monitoring for municipal and industrial wastewater discharge permits under China’s “Water Pollution Prevention and Control Action Plan”
- Source water quality assessment for drinking water treatment plants evaluating halogenated DBP precursors
- Environmental impact assessment (EIA) studies requiring AOX screening prior to chemical manufacturing or pulp/paper facility permitting
- Research on halogenated persistent organic pollutants (POPs), including chlorinated phenols, dioxin precursors, and brominated flame retardant metabolites
- Method validation and interlaboratory comparison studies coordinated by provincial EPB laboratories
FAQ
What standards does the AOX-WK-S comply with?
It is fully configured and validated for HJ 1214–2021. Its core combustion-coulometric methodology aligns with ISO 9562 and historical EPA Method 1650.
Can it measure individual halogens (Cl, Br, I) separately?
No—the system reports total adsorbable organic halogens (AOX) as Cl-equivalents. Speciation requires complementary techniques such as IC-MS or GC-ECD.
Is activated carbon adsorption performed automatically?
Yes—the integrated column adsorption module includes programmable flow control, pressure monitoring, and timed desorption, all synchronized with the combustion sequence.
What maintenance is required for long-term stability?
Routine replacement of quartz combustion tubes every 200–300 analyses, periodic electrolyte refresh in the microcoulometric cell (every 4–6 weeks under daily use), and annual calibration verification using KBr standard solutions.
