Kyoto Kyoritsu WAK-NH4(C)-4 Ammonia Nitrogen (Wastewater) Rapid Test Kit, 0–20 mg/L

Overview

The Kyoto Kyoritsu WAK-NH4(C)-4 Ammonia Nitrogen Rapid Test Kit is a field-deployable, chemically stabilized colorimetric system engineered for the quantitative determination of ammonium nitrogen (NH₄⁺-N) in wastewater effluents and treated discharge streams. It operates on the indophenol blue reaction principle—where ammonia reacts with hypochlorite and phenol under alkaline conditions in the presence of a catalyst (typically sodium nitroprusside) to yield a stable blue chromophore measurable at 630–650 nm. This method is widely recognized for its selectivity toward ionic ammonia in low-turbidity aqueous matrices and is referenced in ISO 7150-1:1984 (Water quality — Determination of ammonium — Spectrophotometric method) and U.S. EPA Method 350.1 (Ammonia — Automated Segmented Flow Analysis). The WAK-NH4(C)-4 variant is specifically calibrated for higher-range wastewater applications (0–20 mg/L), distinguishing it from lower-range variants (e.g., WAK-NH4-4, 0–10 mg/L) by optimized reagent concentrations and pre-configured calibration points.

Key Features

• Pre-measured, lyophilized reagent tablets housed in moisture-resistant aluminum pouches—ensuring shelf stability up to 24 months when stored at 2–8 °C
• Integrated color comparator card with seven fixed reference shades (0, 0.5, 1, 2, 5, 10, 20 mg/L NH₄⁺-N), traceable to NIST-traceable secondary standards
• No external power, spectrophotometer, or pipetting required—measurement relies solely on visual color matching under standardized D65 daylight illumination
• Minimal operator training required; validated for use by plant operators, environmental technicians, and regulatory field inspectors
• Robust interference mitigation: Formulated to suppress common matrix effects from residual chlorine (<2 mg/L), moderate nitrite (<1 mg/L), and turbidity (<50 NTU)
• Each kit contains 50 complete test sequences—including sample vials, reagent tablets, comparator card, and detailed multilingual instructions (English, Japanese, Spanish)

Sample Compatibility & Compliance

The WAK-NH4(C)-4 kit is validated for use with clarified or filtered wastewater samples exhibiting pH 6.5–8.5 and temperature 15–30 °C. Samples with high suspended solids (>100 mg/L), strong oxidants (e.g., >5 mg/L free chlorine), or extreme alkalinity (pH >9.5) require pretreatment—either filtration through 0.45 µm membrane or acidification followed by neutralization. While not intended for primary compliance reporting under GLP or ISO/IEC 17025, the kit meets the performance criteria for screening-level monitoring as defined in ISO 8466-1 (Calibration of analytical instruments) and supports data integrity requirements under EPA’s NPDES permit self-monitoring protocols. Results are suitable for trend analysis, process control feedback, and trigger-based sampling decisions.

Software & Data Management

As a non-instrumented, visual-readout system, the WAK-NH4(C)-4 does not interface with digital software or LIMS platforms. However, Kyoritsu provides a downloadable PDF-based Field Log Template (Rev. 2023), compatible with electronic lab notebooks (ELNs) such as LabArchives and Benchling. Each test record includes fields for sample ID, date/time, analyst initials, ambient conditions, observed color match, and deviation notes—supporting audit-ready documentation. For laboratories requiring digital capture, optional integration with Kyoritsu’s K-Scan mobile app (v4.2+) enables photo-based color matching via calibrated smartphone imaging (requires iOS 15+/Android 12+ and validation per ASTM E3087-21).

Applications

• Effluent monitoring at municipal and industrial wastewater treatment plants (WWTPs) prior to discharge
• Routine checks of nitrification/denitrification basin performance in activated sludge systems
• Verification of ammonia removal efficiency across ion exchange, breakpoint chlorination, or air stripping units
• Field verification of online ammonia analyzers (e.g., Hach NA8000, Endress+Hauser Liquiline CM44P) during commissioning or troubleshooting
• Educational use in environmental technology programs for teaching fundamental nutrient chemistry and method validation principles
• Emergency response screening following spills involving nitrogen-rich compounds (e.g., urea fertilizer, animal waste lagoons)

FAQ

What is the shelf life of an unopened WAK-NH4(C)-4 kit?
Unopened kits retain full performance for 24 months when stored refrigerated (2–8 °C) in original packaging. Do not freeze.
Can this kit measure total ammonia (NH₃ + NH₄⁺) or only ammonium ion?
It measures total ammonia-nitrogen (NH₃-N + NH₄⁺-N) as specified in ISO 7150-1. At typical wastewater pH (6.5–8.5), >90% exists as NH₄⁺; the assay detects both forms equivalently.
Is the comparator card NIST-traceable?
The color standards are manufactured against Kyoritsu’s internal reference set, which is calibrated using NIST SRM 2170a (Ammonium Nitrogen Standard Solution); full traceability documentation is available upon request.
How should I handle samples with high chloride concentration?
Chloride up to 2,000 mg/L does not interfere. Above that, add 1 drop of 10% sodium thiosulfate solution to quench residual oxidants before adding reagents.
Does this kit comply with ISO/IEC 17025 for accredited testing?
No—it is designed for screening and process control, not definitive compliance testing. Accredited labs must validate the method per ISO/IEC 17025 clause 7.2.2 before using it for reported results.