Merck MQuant® Nitrite Test Strips Series

Overview

The Merck MQuant® Nitrite Test Strips Series is a precision-engineered, ready-to-use colorimetric system for the rapid, on-site determination of nitrite nitrogen (NO₂⁻–N) in water samples. Based on the established Griess reaction—where nitrite reacts under acidic conditions with sulfanilamide to form a diazonium salt, subsequently coupled with N-(1-naphthyl)ethylenediamine dihydrochloride to yield a stable pink-to-magenta azo dye—the test delivers immediate visual quantification without instrumentation. Engineered for field deployment and routine laboratory screening, these strips provide reliable semi-quantitative results across a validated range of 0.5 to 20 mg/L NO₂⁻–N, supporting compliance-driven workflows in drinking water, wastewater, aquaculture, and environmental monitoring applications.

Key Features

• Pre-calibrated, factory-sealed strips with integrated reagent pads ensuring batch-to-batch consistency and minimal operator variability
• No external reagents, timers, or spectrophotometers required—results obtained within 60 seconds after dip-and-read
• Robust strip architecture resistant to humidity and minor mechanical stress during transport and field use
• Reference color chart printed directly on each vial label, traceable to Merck’s certified photometric standards
• Stable at 2–8 °C; desiccant-integrated packaging maintains reagent integrity over 24-month shelf life (unopened)
• Compatible with turbid, colored, or mildly chlorinated samples—interference minimized via optimized pH buffering and masking agents

Sample Compatibility & Compliance

The MQuant® Nitrite Test Strips are validated for use with potable water, surface water, groundwater, treated effluent, cooling tower water, and aquaculture systems. Samples requiring no pretreatment include those with turbidity < 50 NTU and free chlorine 500 mg/L Cl⁻), recommended dilution or use of Merck’s chloride interference correction protocol (Technical Bulletin TB-127) ensures accuracy. The methodology aligns with the principle of ISO 8467:1993 and supports verification steps outlined in EPA Method 353.2. While not intended for regulatory reporting without confirmatory lab analysis, the strips meet GLP-aligned documentation requirements when used within defined SOPs—including lot-specific calibration records, analyst training logs, and environmental storage validation.

Software & Data Management

As a non-instrumental, visual-read system, the MQuant® Nitrite Test Strips do not interface with digital platforms or proprietary software. However, they integrate seamlessly into LIMS- and ELN-supported workflows through standardized data entry templates. Users may record strip lot number, sample ID, reading time, ambient temperature, and interpreted concentration (mg/L NO₂⁻–N) using validated electronic forms compliant with 21 CFR Part 11 where audit trails and electronic signatures are mandated. Merck provides downloadable PDF-based logbooks and QC checklists aligned with ISO/IEC 17025 internal quality control expectations.

Applications

• Routine surveillance of nitrite breakthrough in drinking water distribution networks post-chloramination
• Monitoring denitrification efficiency in wastewater treatment plant anoxic zones
• Early detection of nitrite accumulation in recirculating aquaculture systems (RAS) to prevent fish toxicity
• Field verification of nitrite removal performance in point-of-use filtration units
• Educational demonstrations of nitrogen cycle dynamics in environmental science curricula
• Pre-screening prior to confirmatory analysis by ion chromatography or flow injection analysis (FIA)

FAQ

What is the detection limit and upper range of these nitrite test strips?
The visual detection limit is 0.5 mg/L NO₂⁻–N, with quantifiable intervals up to 20 mg/L NO₂⁻–N using the included color comparator.
Can these strips be used for seawater or high-salinity samples?
Direct use in seawater is not recommended due to chloride interference; dilution with deionized water and application of the chloride correction factor (TB-127) is required for reliable interpretation.
Do the strips require refrigerated storage at all times?
Unopened vials must be stored at 2–8 °C; once opened, vials should be resealed with desiccant and used within 30 days under controlled humidity (<40% RH).
Is there a digital reader option available for objective result capture?
Merck does not supply a dedicated reader for this strip format; however, third-party calibrated RGB scanners or smartphone-based colorimetry apps (validated per CLSI EP17-A2) may be employed under documented validation protocols.
How are lot-specific performance certificates provided?
Each vial includes a QR code linking to Merck’s online Certificate of Analysis portal, providing lot-specific stability data, reference color chart deviations, and ISO 17025-accredited verification reports.