DELEITE NQT-100i Intelligent Total Nitrogen Analyzer

Overview

The DELEITE NQT-100i Intelligent Total Nitrogen Analyzer is a dedicated benchtop spectrophotometric instrument engineered for rapid, accurate quantification of total nitrogen (TN) in aqueous environmental samples. It implements the standardized alkaline potassium persulfate digestion method followed by ultraviolet (UV) absorbance measurement at 220 nm and 275 nm—fully compliant with HJ 636–2012, the official Chinese standard for TN determination in water. The system integrates digestion and photometric analysis into a streamlined workflow: samples undergo high-efficiency thermal oxidation in an integrated or companion digestion unit to convert all nitrogen species (organic N, ammonia, nitrate, nitrite) into nitrate, which is then quantified via dual-wavelength UV spectrophotometry with automatic correction for dissolved organic carbon interference. Designed for routine monitoring in regulatory, municipal, and industrial laboratories, the NQT-100i delivers robust performance under variable sample matrices while maintaining traceable metrological integrity.

Key Features

• Full-spectrum holographic grating optical system (190–1000 nm) with automated wavelength selection and direct concentration readout
• Integrated 8-position motorized cuvette carousel enabling sequential, unattended analysis of up to eight samples per run
• One-touch dilution function for automatic handling of high-concentration samples beyond the 100 mg/L upper limit
• Embedded 10-inch detachable Android-based tablet with intuitive, guided user interface—designed to minimize operator training time and procedural errors
• Self-calibrating optical path: instrument performs automatic baseline validation and curve generation using certified reference standards; eliminates manual calibration curve preparation
• Dual-function capability: operates as both a dedicated TN analyzer and a general-purpose UV-Vis spectrophotometer for method development and auxiliary assays
• High-stability deuterium/tungsten light source (100,000-hour rated lifetime) with photometric drift ≤0.001 A over 20 minutes
• Comprehensive connectivity: USB 2.0, RS232 serial port, Bluetooth 5.0, and Ethernet support for data export, remote diagnostics, and LIMS integration

Sample Compatibility & Compliance

The NQT-100i is validated for use with surface water, groundwater, wastewater effluents, industrial process streams, and pretreated sludge filtrates. Its digestion protocol ensures complete oxidation of refractory nitrogen compounds—including pyrroles, indoles, and heterocyclic organics—when paired with the supplied pre-optimized alkaline persulfate reagents. All hardware and firmware comply with IEC 61010-1 (safety requirements for electrical equipment) and electromagnetic compatibility (EMC) directives per CISPR 11. Data acquisition and storage meet GLP documentation requirements, including timestamped measurement logs, operator ID tagging, and audit-trail-capable event history. While not FDA 21 CFR Part 11–certified out-of-the-box, the platform supports configurable electronic signature workflows and encrypted data export formats (CSV, PDF, XML) suitable for regulated environments upon local validation.

Software & Data Management

The proprietary “AquaIntelli Platform” software provides role-based access control, multi-user account management, and method library versioning. Each assay includes built-in QC checks: blank verification, linearity assessment across three points, and recovery spike validation prompts. Raw absorbance values (A₂₂₀, A₂₇₅) and calculated TN concentrations are stored with full metadata (digestion temperature/time, reagent lot, instrument ID, environmental conditions). Export options include direct printing via Bluetooth or network-enabled thermal printers, cloud sync to secure SFTP servers, and batch transfer to laboratory information management systems (LIMS) via HL7 or ASTM E1384-compliant interfaces. Software updates are delivered OTA (over-the-air) with SHA-256 signature verification.

Applications

The NQT-100i serves as a core analytical tool in environmental compliance laboratories performing discharge monitoring (e.g., municipal WWTP effluent reporting), watershed health assessments, and industrial pretreatment verification. It is routinely deployed in R&D settings for evaluating denitrification efficiency in bioreactors, optimizing coagulation-flocculation processes, and validating membrane filtration performance. Cross-sector adoption includes petrochemical facilities tracking nitrogen load in cooling tower blowdown, pharmaceutical manufacturers verifying cleaning validation rinse water, and aquaculture operations managing nutrient budgets in recirculating systems. Its adaptability extends to educational labs for teaching redox chemistry, spectrophotometric principles, and environmental regulatory frameworks.

FAQ

Does the NQT-100i require external digestion equipment?
No—the system is designed to operate with a companion DELEITE digestion module (sold separately), but it accepts pre-digested samples from any ISO/IEC 17025-accredited digestion unit meeting HJ 636–2012 thermal specifications (120–124 °C, 30 min).
Can the instrument store multiple calibration curves for different matrix types?
Yes—up to 50 user-defined calibration sets can be saved, each associated with specific sample categories (e.g., “wastewater,” “drinking water,” “seawater digestate”) and linked to unique correction factors.
Is method validation documentation provided?
DELEITE supplies a comprehensive Instrument Qualification Package (IQ/OQ) aligned with ISO/IEC 17025 Annex A, including precision, accuracy, LOD/LOQ, and ruggedness test reports conducted per ICH Q2(R2) guidelines.
What maintenance is required for long-term optical stability?
Annual verification of wavelength accuracy (using holmium oxide and didymium filters) and photometric linearity (neutral density filters) is recommended; no lamp alignment or grating recalibration is user-serviceable.
Are reagents supplied with the instrument compatible with international equivalents?
Yes—the included alkaline persulfate reagents conform to purity specifications outlined in ASTM D129–18 and are functionally interchangeable with Sigma-Aldrich, Merck, or Hach branded kits when prepared per HJ 636–2012 protocols.