HACH Nitrate Pre-Mixed Reagent Series for Water Quality Analysis

Overview

HACH Nitrate Pre-Mixed Reagent Series delivers standardized, traceable, and method-validated chemistry for accurate nitrate (NO₃⁻) quantification in drinking water, wastewater, surface water, and groundwater samples. Engineered for compliance with EPA Method 353.2 (cadmium reduction), Standard Methods 4500-NO₃⁻ F (chromotropic acid), and USP (for purified water monitoring), each reagent formulation undergoes rigorous lot-to-lot performance verification against NIST-traceable nitrate standards. The series eliminates manual reagent preparation—reducing analyst error, minimizing exposure to hazardous chemicals (e.g., cadmium granules, strong acids), and ensuring consistent reaction kinetics and color development across laboratories. All reagents are manufactured under ISO 9001-certified processes at HACH’s facility in Loveland, Colorado, USA, and shipped with full Certificate of Analysis (CoA) including batch-specific calibration curves and stability data.

Key Features

• Method-Specific Optimization: Three distinct chemistries address diverse regulatory and sensitivity requirements—cadmium reduction for low-range environmental monitoring (0.01–0.50 mg/L), chromotropic acid for mid-range industrial effluent (0.2–30.0 mg/L), and xylenol orange (TNTplus) for high-salinity or turbid matrices with enhanced interference rejection.
• Pre-Calibrated & Ready-to-Use: Each vial or tube contains precisely dosed reagents, buffers, and catalysts—no weighing, dilution, or pH adjustment required. Eliminates variability from technician technique and ambient humidity effects on solid reagents.
• Extended Shelf Stability: Refrigerated (2–8°C) shelf life up to 24 months for cadmium-based kits; 36 months for TNTplus formulations. Individually sealed packaging prevents moisture ingress and cross-contamination.
• Instrument Interoperability: Fully validated for use with HACH’s full portfolio of spectrophotometers—including DR6000 (with built-in nitrate methods), DR3900, DR1900, and portable platforms such as DR900 and Pocket Colorimeter II—ensuring seamless method recall, auto-wavelength selection, and integrated calibration verification.
• GLP/GMP-Ready Documentation: Each lot includes a CoA with lot number, expiry date, certified reference material (CRM) traceability, and documented uncertainty (k=2). Supports audit readiness for ISO/IEC 17025, EPA NPDES, and pharmaceutical water system validation (USP ).

Sample Compatibility & Compliance

The Nitrate Pre-Mixed Reagent Series is validated for use with clarified, filtered, or centrifuged aqueous samples containing ≤500 mg/L total suspended solids (TSS) and ≤2000 µS/cm conductivity. Interference testing confirms robustness against common matrix components: chloride (≤1000 mg/L), sulfate (≤500 mg/L), phosphate (≤5 mg/L), and dissolved organic carbon (≤10 mg/L DOC). For wastewater or seawater applications, the TNT835-CN and TNT836-CN kits incorporate proprietary masking agents that suppress color quenching from iron(III), manganese(II), and residual chlorine. All methods comply with ASTM D3867–22 (Standard Test Method for Nitrate in Water by Cadmium Reduction), ISO 7890-3:2022 (Water quality — Determination of nitrate — Part 3: Cadmium reduction method), and EU Directive 2020/2184 (Drinking Water Directive Annex II parameters).

Software & Data Management

When used with HACH’s AquaTrack™ software or the instrument’s native firmware (v6.1+), reagent lot data auto-populates method metadata fields—including expiration tracking, calibration curve version, and CRM batch linkage. Spectrophotometric measurements generate audit-trail logs compliant with FDA 21 CFR Part 11 (electronic records/signatures) when paired with user authentication and instrument-level access controls. Raw absorbance values, corrected for blank drift, and calculated concentrations are exportable in CSV or LIMS-compatible XML formats. Method templates for all six catalog numbers (e.g., 2106169-CN, TNT836-CN) are pre-loaded in DR6000 firmware and synchronized via HACH Connect cloud platform.

Applications

• Regulatory compliance monitoring for municipal drinking water utilities (EPA UCMR, SDWA)
• Wastewater treatment plant effluent reporting (NPDES permits)
• Agricultural runoff and watershed nutrient loading studies
• Pharmaceutical purified water and water-for-injection (WFI) system qualification
• Environmental site assessment (ESA) and brownfield remediation verification
• Educational laboratory instruction for analytical chemistry and environmental science curricula

FAQ

Are these reagents compatible with non-HACH spectrophotometers?
Yes—provided the instrument supports user-defined wavelength selection (e.g., 500 nm for cadmium reduction, 540 nm for chromotropic, 570 nm for TNTplus) and has sufficient photometric accuracy (±0.005 AU at 1.0 AU). However, method validation and calibration must be performed independently per ISO/IEC 17025 Clause 5.4.
What is the recommended sample filtration protocol prior to analysis?
Filter samples through a 0.45 µm membrane (cellulose acetate or polyethersulfone) using vacuum or syringe filtration. Avoid nitrocellulose filters due to potential nitrate leaching. Rinse filter and apparatus with deionized water before sample passage.
Do TNTplus reagents require digestion or heating steps?
No—TNT835-CN and TNT836-CN are room-temperature, single-step reactions with 3-minute color development. No boiling, autoclaving, or catalyst addition is required.
How is cadmium waste managed after using cadmium reduction reagents?
Spent cadmium-reduction cartridges (e.g., from 2106169-CN) must be disposed of as hazardous waste per local RCRA/EPA 40 CFR Part 261 regulations. HACH provides SDS-compliant waste handling guidelines and offers certified return programs for spent columns in North America and EU member states.