Kyoritsu WAK-CN-2 Free Cyanide Test Kit for Water Quality Analysis

Overview

The Kyoritsu WAK-CN-2 Free Cyanide Test Kit is a portable, single-use colorimetric assay system engineered for rapid, on-site quantification of free (non-complexed) cyanide ions (CN⁻) in water samples. It operates on the classical pyridine-barbituric acid (PBA) color development principle: under acidic conditions and with controlled distillation pretreatment (performed separately prior to test strip immersion), free cyanide is liberated, reacts with chloramine-T to form cyanogen chloride, and subsequently couples with pyridine and barbituric acid to yield a pink-to-magenta chromophore. The intensity of the developed color—visually compared against a calibrated reference scale—is directly proportional to the free cyanide concentration. This method is aligned with the foundational chemistry of ISO 6703-1 and serves as a validated screening tool for environmental monitoring, wastewater compliance checks, and emergency response scenarios where laboratory access is limited.

Key Features

• Pre-calibrated visual color scale printed directly on the test card, enabling direct interpretation without instrumentation
• Dry-reagent impregnated test strips with stabilized reagents—no liquid reagents to handle, measure, or store
• Optimized for field use: lightweight, compact packaging (40 tests per kit), no power or calibration required
• Controlled reaction kinetics: standardized 8-minute development time ensures reproducible color formation across ambient temperatures (15–30 °C)
• Robust interference mitigation: built-in masking agents reduce impact from common anions (e.g., sulfide, nitrite) when sample pretreatment protocols are followed
• Trace-level detection: lower limit of visual detection at <0.02 mg/L CN⁻, supporting regulatory thresholds for drinking water (e.g., WHO guideline: 0.07 mg/L) and surface water classification

Sample Compatibility & Compliance

The WAK-CN-2 kit is validated for use with clarified, non-turbid aqueous matrices including surface water, groundwater, treated effluent, and industrial process water. Samples containing high suspended solids, extreme pH (10), or strong oxidants must undergo filtration and pH adjustment prior to analysis. While not a definitive regulatory method per se, the kit’s underlying chemistry conforms to the distillation-based free cyanide determination framework specified in ISO 6703-1 and supports preliminary assessment under EPA Method 9010B (Cyanide, Amenable) and ASTM D4374-22 (Standard Test Methods for Cyanides in Water). It is routinely employed in GLP-aligned field screening programs where documented chain-of-custody and procedural adherence—including recorded lot numbers, expiration dates, and operator initials—are maintained for audit readiness.

Software & Data Management

As a manual visual test system, the WAK-CN-2 does not incorporate embedded software or digital data output. However, Kyoritsu provides complementary documentation tools: downloadable PDF record sheets (with space for sample ID, date/time, operator, observed color match, calculated result, and remarks) support traceable paper-based reporting. For laboratories integrating WAK-CN-2 into LIMS workflows, scanned records or manually entered results can be linked to sample IDs and batch logs. When used alongside Kyoritsu’s digital photometric readers (e.g., KRM-200 series), optional image capture and semi-quantitative analysis via RGB intensity profiling may be performed—though such configurations require separate validation per ISO/IEC 17025 requirements.

Applications

• Routine surveillance of municipal and industrial wastewater discharge points for pre-treatment verification
• Emergency response screening following suspected cyanide spills or leaching events near mining or electroplating facilities
• Field validation of treatment efficacy in activated carbon or hydrogen peroxide oxidation systems targeting cyanide destruction
• Educational demonstrations of redox-based colorimetric assays in environmental science curricula
• Baseline characterization during environmental site assessments (ESAs) where rapid presence/absence or semi-quantitative data inform subsequent lab-based ICP-MS or ion chromatography analysis

FAQ

Is the WAK-CN-2 kit suitable for measuring total cyanide?
No. This kit detects only free cyanide (HCN/CN⁻). Total cyanide requires acid distillation under stronger conditions (e.g., ASTM D7282) and is not covered by this assay.
Can seawater samples be analyzed directly?
No. High chloride concentrations interfere with color development. Desalination or dilution with deionized water—followed by matrix spike recovery verification—is required before testing.
What is the shelf life and storage requirement?
Unopened kits retain stability for 24 months when stored at 2–30 °C in dry, dark conditions. Avoid freezing or exposure to humidity above 70% RH.
Does the kit comply with FDA 21 CFR Part 11?
No—this is a manual visual method with no electronic records or audit trails. It is intended for screening, not regulated release testing under cGMP.
How should results be reported for regulatory submissions?
Results must be accompanied by full method documentation, including lot-specific certificate of analysis, observed color match, and confirmation that sample pretreatment (distillation, pH adjustment, filtration) was performed per Kyoritsu’s technical bulletin TB-WAK-CN-2 Rev. 3.