Shenchanghong TNH-6N Ammonia Nitrogen Analyzer

Overview

The Shenchanghong TNH-6N Ammonia Nitrogen Analyzer is a dedicated benchtop photometric instrument engineered for precise, rapid quantification of ammonia nitrogen (NH₃–N) in aqueous environmental samples. It implements the standardized Nessler colorimetric method—defined in ISO 7150-1:1984 and EPA Method 350.1—where ammonia reacts with Nessler’s reagent to form a yellow-brown colloidal complex proportional to concentration. Absorbance is measured at 420 nm using a cold-light LED source and narrow-band optical interference filter, minimizing thermal drift and spectral interference. Designed for routine compliance monitoring in municipal, industrial, and research laboratories, the TNH-6N delivers trace-level sensitivity (LOD = 0.02 mg/L) and high reproducibility (RSD ≤3%) under GLP-aligned operational conditions.

Key Features

• Cold-light LED optical system with narrow-band interference filter (center wavelength: 420 nm), ensuring long-term photometric stability (≤0.002 A/20 min) and immunity to ambient temperature fluctuations.
• 7-inch capacitive touchscreen interface with dual-language support (English and Simplified Chinese), intuitive icon-driven workflow, and real-time graphical feedback during calibration and measurement.
• Integrated self-calibration function enabling on-demand verification and correction of baseline drift—critical for extended daily operation without external reference standards.
• One-touch system recovery mode to restore factory default settings, calibration curves, and user configurations in case of accidental modification or software anomaly.
• Non-volatile flash memory storing up to 3,500 user-defined calibration curves and 100,000 measurement records—including full metadata: standard concentration values, corresponding absorbance readings, calibration date/time, and operator ID—for full traceability and audit readiness.
• USB 2.0 interface compliant with standard mass-storage class protocols, allowing direct data transfer to Windows-based PCs without proprietary drivers; compatible with common spreadsheet and LIMS import formats (CSV, TXT).
• Onboard thermal printer support (optional accessory) for immediate hardcopy generation of individual results or full report pages—including sample ID, time stamp, curve ID, and QC flags.

Sample Compatibility & Compliance

The TNH-6N is validated for use with clarified, non-turbid water matrices including surface water, groundwater, domestic wastewater effluent, and treated industrial discharge. Samples requiring pretreatment (e.g., filtration through 0.45 µm membrane, pH adjustment, or removal of interfering ions such as Ca²⁺/Mg²⁺ via chelation) must follow ISO 5667-3:2018 guidelines prior to analysis. The instrument meets core functional requirements of ISO/IEC 17025:2017 for testing laboratories, and its documented calibration traceability, data integrity controls (timestamped records, operator ID logging), and non-volatile storage align with principles of FDA 21 CFR Part 11 for electronic records where local regulatory policy permits. It is not designed for seawater, highly colored, or suspended-solids-rich samples (>50 NTU) without prior dilution or digestion.

Software & Data Management

No standalone software installation is required: the TNH-6N operates autonomously with embedded firmware supporting complete method execution—from reagent addition prompts to final concentration calculation. All calibration and measurement data are stored internally with ISO-compliant metadata fields. When connected via USB, the device appears as a removable drive; exported CSV files contain columns for Sample ID, Date/Time, Curve ID, Absorbance (A), Concentration (mg/L), and QC Status (e.g., “In-Range”, “Outlier”). Audit trail functionality includes automatic logging of all calibration events, curve modifications, and system resets—accessible via on-screen history browser or exported logs. Data export supports integration into laboratory information management systems (LIMS) or statistical process control (SPC) platforms.

Applications

• Regulatory compliance monitoring of NH₃–N in municipal wastewater treatment plant influent, effluent, and receiving waters per national discharge standards (e.g., China’s GB 3838–2002, EU Urban Wastewater Treatment Directive 91/271/EEC).
• Process control in aquaculture facilities, where sub-ppm shifts in ammonia concentration directly impact fish health and biofilter efficiency.
• Environmental impact assessment (EIA) field labs performing rapid screening of river, lake, and reservoir samples during seasonal nutrient surveys.
• Academic and teaching laboratories conducting water chemistry experiments aligned with APHA Standard Methods 4500-NH₃ F and ASTM D1426–15.
• Industrial QA/QC for cooling tower water, boiler feedwater, and semiconductor rinse water where low-level ammonia contamination affects corrosion rates or product purity.

FAQ

What reagents are required for operation, and are they included in the standard configuration?
The instrument ships with one set of Nessler reagent (powder or liquid formulation, depending on regional regulatory approval), sufficient for approximately 200 measurements. Reagent kits are supplied in sealed, light-protected vials with lot-specific certificates of analysis. Users must procure replacements from authorized Shenchanghong distributors to ensure method consistency.
Can the TNH-6N be used for continuous online monitoring?
No—the TNH-6N is a discrete batch analyzer intended for manual sample loading. It does not support automated sampling, flow-cell integration, or 24/7 unattended operation. For continuous applications, refer to Shenchanghong’s TNH-Online series with integrated peristaltic pumps and digital I/O interfaces.
Is method validation documentation available for regulatory submission?
Yes—upon request, Shenchanghong provides a Method Validation Report (MVR) detailing precision, accuracy, linearity (r² ≥0.999 over 0.02–25 mg/L), limit of detection (LOD), limit of quantitation (LOQ), and interferences testing per ISO/IEC 17025 Annex B guidelines.
How often should optical alignment or lamp replacement be performed?
The cold-light LED source has a rated lifetime exceeding 100,000 hours. No routine optical alignment is required. Annual verification using certified neutral density filters (NIST-traceable) is recommended as part of preventive maintenance.
Does the instrument support multi-point calibration with custom curve fitting (e.g., quadratic or cubic)?
Yes—users may define up to 8-point calibration sets and select linear, quadratic, or forced-zero linear regression models. All curve parameters, residuals, and goodness-of-fit metrics (e.g., standard error of estimate) are displayed and stored with each calibration event.