Shenchanghong CHYN-231 Nitrate Analyzer

Overview

The Shenchanghong CHYN-231 Nitrate Analyzer is a dedicated spectrophotometric instrument engineered for the quantitative determination of nitrate nitrogen (NO₃⁻-N) in aqueous matrices using the ultraviolet (UV) absorption method—specifically, the UV spectrophotometric principle at 220 nm, with correction at 275 nm to minimize interference from dissolved organic matter and turbidity. Designed for routine laboratory use in environmental monitoring laboratories, municipal water utilities, wastewater treatment facilities, academic institutions, and research centers, the CHYN-231 delivers reliable, repeatable results without requiring complex reagent preparation or hazardous chemical handling typical of classical cadmium reduction or Griess-based colorimetric methods. Its optical architecture integrates a high-stability, long-life (≥100,000 hours) UV LED source and precision narrow-band interference filters, ensuring minimal drift and high photometric reproducibility across extended operational cycles.

Key Features

• 16-bit low-power microcontroller platform optimized for stable signal acquisition, real-time calibration, and embedded algorithmic correction (e.g., dual-wavelength baseline compensation).
• Optical system featuring imported UV LEDs and thermally stabilized narrow-band filters (center wavelength ±1 nm tolerance), delivering high photometric linearity (R² > 0.999 over 0.02–10.00 mg/L range) and resistance to ambient light interference.
• Backlit monochrome LCD display with full Chinese-language interface and intuitive menu navigation—designed for ease of operation by technicians with varying levels of spectroscopic training.
• Onboard data storage supporting ≥500 measurement records with timestamp, sample ID, and calibration batch reference—retained after power-off without external memory or battery backup.
• User-definable calibration curve functionality: pre-loaded factory calibration curve (NIST-traceable standards used during verification) plus space for up to three custom calibration sets, each with slope, intercept, and correlation coefficient logging.
• Durable housing constructed from post-molded ABS polymer with enhanced chemical resistance to common laboratory cleaning agents, chlorinated disinfectants, and mildly acidic/basic aqueous samples.

Sample Compatibility & Compliance

The CHYN-231 is validated for use with clarified, non-turbid water samples including potable water, groundwater, surface water, and treated effluent. Prior filtration (≤0.45 µm membrane) is recommended for samples containing suspended solids. The analyzer complies with fundamental performance criteria outlined in ISO 10301:2021 (Water quality — Determination of nitrate — UV spectrometric method) and aligns with methodological principles referenced in EPA Method 353.2 (Determination of Nitrate/Nitrite Nitrogen by Automated Cadmium Reduction). While not certified under GLP or ISO/IEC 17025 as a standalone system, its design supports traceable calibration practices, audit-ready data logging, and documented instrument qualification (IQ/OQ) when integrated into laboratory quality management systems adhering to ISO/IEC 17025:2017 or CNAS-CL01 requirements.

Software & Data Management

Data export is supported via USB 2.0 interface (device mode) to standard USB flash drives in CSV format—no proprietary software required. Each exported file includes column headers: Timestamp (YYYY-MM-DD HH:MM:SS), Sample ID, Measured Concentration (mg/L NO₃⁻-N), Calibration Curve ID, Operator Code (user-entered), and QC Flag (if value falls outside defined control limits). Audit trail functionality is implemented at firmware level: all calibration events, zero adjustments, and curve modifications are time-stamped and logged internally with immutable timestamps. The system does not support remote connectivity, cloud synchronization, or FDA 21 CFR Part 11-compliant electronic signatures; however, its local logging structure satisfies basic ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate) for non-regulated environmental testing environments.

Applications

• Compliance monitoring of nitrate levels in drinking water supplies against WHO guideline values (≤50 mg/L NO₃⁻) and national standards (e.g., GB 5749-2022, US EPA MCL of 10 mg/L NO₃⁻-N).
• Process control in wastewater treatment plants—tracking nitrate removal efficiency across denitrification stages.
• Groundwater vulnerability assessment in agricultural zones where fertilizer leaching is suspected.
• Academic teaching labs for undergraduate environmental chemistry courses covering nutrient cycling and instrumental analysis fundamentals.
• Field-deployable screening in mobile environmental labs—enabled by compact footprint, low mass (1.0 kg), and AC-powered operation with optional external battery pack (not included).

FAQ

What measurement principle does the CHYN-231 employ?
It uses dual-wavelength UV spectrophotometry at 220 nm (primary absorbance peak of nitrate ion) and 275 nm (correction wavelength for organic interference), calculating concentration via Beer-Lambert law with built-in pathlength normalization.
Is the instrument suitable for wastewater with high turbidity?
No—samples must be filtered through a 0.45 µm membrane prior to analysis to avoid scattering artifacts; unfiltered wastewater may yield falsely elevated readings.
Can calibration curves be transferred between instruments?
No—calibration is instrument-specific due to LED spectral drift and filter tolerance variations; each unit requires independent standardization using certified reference materials.
Does the CHYN-231 require annual recalibration by the manufacturer?
Not mandatory; users may perform verification with NIST-traceable nitrate standards (e.g., CRM 1001a) at quarterly intervals per internal SOP, with full recalibration triggered only upon failure of verification checks.
Is there a version compatible with PC-based LIMS integration?
The base CHYN-231 model lacks Ethernet, RS-232, or API interfaces; LIMS linkage requires manual CSV import or third-party middleware solutions handling USB mass-storage polling.