Raykol RK-9870A / RK-9870B Fully Automated Kjeldahl Nitrogen Analyzer
| Brand | Raykol |
|---|---|
| Origin | Fujian, China |
| Manufacturer Type | Manufacturer |
| Instrument Type | Kjeldahl Nitrogen Analyzer |
| Automation Level | Fully Automated |
| Nitrogen Determination Range | 0.1 mg – 240 mg N |
| Steam Distillation Time Setting | 10–9990 s (adjustable) |
| Repeatability | ≤0.5% RSD |
| Sample Weight Capacity | Solids ≤5.00 g |
| Ammonia Recovery Rate | 99–101% |
| Power Consumption | 2000 W |
| Dimensions (L×W×H) | 500 mm × 460 mm × 710 mm |
Overview
The Raykol RK-9870A and RK-9870B are fully automated Kjeldahl nitrogen analyzers engineered for high-throughput, regulatory-compliant total nitrogen and protein quantification in agricultural, food, feed, and environmental laboratories. Based on the classical Kjeldahl digestion–distillation–titration principle, these instruments perform acid digestion of organic nitrogen into ammonium sulfate, alkaline steam distillation to liberate ammonia, quantitative absorption into standardized sulfuric acid, and potentiometric or photometric back-titration with sodium hydroxide. The system implements the standardized endpoint detection method specified in major international and national protocols—including ASTM D1193, ISO 5983-1:2009, and AOAC Official Method 984.13—using a dual-wavelength RGB coaxial optical sensor for robust colorimetric recognition of the methyl red–methylene blue indicator transition (pH 5.4 ± 0.2). Designed for unattended operation, the RK-9870 series integrates digestion residue handling, steam generation, condensation, titration, and data reporting within a single compact architecture.
Key Features
- 10-inch industrial-grade color touchscreen HMI enabling unified control of distillation unit, cooling system, titration module, and reagent delivery—eliminating discrete hardware switches and reducing operator error.
- Integrated refrigerated condenser with 304 stainless steel heat exchanger core, reducing water consumption by >90% versus traditional tap-cooled systems while maintaining thermal stability across extended batch runs.
- Triple-tier electronic access control (Administrator/Supervisor/Operator) with audit-trail-enabled electronic signatures, time-stamped event logs, and user-specific permission profiles compliant with FDA 21 CFR Part 11 and GLP/GMP documentation requirements.
- Auto-shutdown after 60 minutes of inactivity, coupled with automatic alkaline line rinsing post-analysis to prevent crystallization and ensure long-term volumetric accuracy.
- Onboard protein conversion factor database (e.g., 6.25 for general food, 5.70 for wheat, 6.38 for dairy) supporting configurable sample-specific calculation and direct export of % protein results.
- Simultaneous steam distillation and titration mode reduces cycle time by up to 35% compared to sequential operation, without compromising endpoint precision or recovery fidelity.
- Steam flow rate continuously adjustable from 0–100% via PID-controlled boiler pressure regulation, enabling method optimization for low-nitrogen fertilizers or high-protein dairy samples.
- Full-spectrum RGB photometric titration system with adaptive gain compensation ensures reliable endpoint detection across variable sample matrix colors—including turbid digestates and pigmented extracts—without manual threshold adjustment.
Sample Compatibility & Compliance
The RK-9870A/B accommodates solid samples up to 5.00 g (e.g., granular NPK fertilizers, soil amendments, animal feed pellets) and liquid samples up to 20 mL (e.g., liquid fertilizers, hydrolysates, wastewater digests). It meets the procedural and performance criteria defined in GB/T 8572–2010 (determination of total nitrogen in compound fertilizers), GB/T 17767.1–2008 (organic–inorganic compound fertilizers), NY/T 1977–2010 (liquid fertilizers), and NY/T 1116–2014 (microelement fertilizers). All critical process parameters—including digestion temperature ramp profiles, distillation steam pressure, condensate temperature stability (±0.5 °C), and titrant delivery resolution (0.01 mL increments)—are logged with traceable timestamps and linked to individual sample IDs. System validation reports support IQ/OQ/PQ execution per ISO/IEC 17025 and internal quality management frameworks.
Software & Data Management
The RK-9870A operates via embedded Linux-based firmware with local data storage capacity exceeding 1 million test records (including raw absorbance curves, titration curves, reagent usage logs, and environmental sensor readings). The RK-9870B extends functionality with a pre-installed Windows 10 IoT Enterprise OS, enabling native integration with LIMS via OPC UA or HL7, automated PDF report generation (with customizable templates, digital signatures, and watermarking), and remote diagnostic telemetry over LAN/Wi-Fi/Ethernet. All communication interfaces—RS232, USB host/device, CAN bus, and TCP/IP—are isolated and support bidirectional handshake protocols. Electronic balance integration enables direct sample mass upload via ASCII or METTLER Toledo-compatible command sets, eliminating manual weight entry and associated transcription errors.
Applications
Primary application domains include quality control laboratories in fertilizer manufacturing (NPK, urea, ammonium nitrate blends), contract testing facilities serving agronomic research institutions, regulatory agencies performing routine surveillance of nutrient labeling compliance, and academic departments conducting method validation studies. The instrument supports multi-step workflows such as sequential macro-Kjeldahl analysis of mixed fertilizer batches, parallel digestion of soil–plant tissue composites, and rapid screening of biogas digestate nitrogen speciation. Its robust mechanical design and corrosion-resistant 304 stainless steel steam generator, condenser, and waste manifold ensure operational continuity in high-humidity, chemically aggressive environments typical of central analytical labs.
FAQ
Does the RK-9870B support LIMS connectivity?
Yes—the RK-9870B includes native drivers for common LIMS platforms via ASTM E1384-compliant messaging and configurable CSV/Excel export templates.
What safety mechanisms prevent overheating or overpressure during distillation?
Dual redundant safeguards: real-time steam boiler temperature monitoring with automatic cut-off at 210 °C, and independent pressure transducer feedback triggering immediate steam valve closure if pressure exceeds 0.25 MPa.
Can the system be validated for ISO/IEC 17025 accreditation?
Yes—full validation documentation package (including installation qualification checklists, operational qualification protocols, and performance verification data for recovery, repeatability, and linearity) is provided with each unit.
Is external cooling water required for the RK-9870A/B?
No—the integrated closed-loop refrigeration system eliminates dependency on municipal water supply, making it suitable for laboratories with restricted water access or sustainability mandates.
How is calibration traceability maintained for titrant delivery?
Each titration syringe undergoes factory gravimetric calibration against NIST-traceable standards; recalibration certificates and drift logs are stored in the audit trail and exportable upon request.
