MICHEM MD Series Microwave Digestion and Extraction System
| Brand | MICHEM |
|---|---|
| Model | MD Series |
| Origin | Beijing, China |
| Microwave Frequency | 2450 ±13 MHz |
| Output Power | 1200 W |
| Power Control | 0–100% PID Automatic Continuous Adjustment |
| Cavity Volume | 45 L |
| Dimensions (W×D×H) | 490 × 610 × 610 mm |
| Net Weight | 48 kg |
| Temperature Range | 0–300 °C |
| Temperature Accuracy | ±0.5 °C |
| Pressure Range | 0–6 MPa |
| Pressure Accuracy | ±0.05 MPa |
| Microwave Leakage | ≤0.3 mW/cm² |
| Cavity Coating | Dupont PFA |
| Outer Vessel Material | PEEK (10 MPa burst rating) |
| Inner Vessel Material | TFM (chemically resistant, up to 300 °C) |
| Cooling Airflow | 3 m³/min (cooling to safe opening temperature within 20 min) |
| Door Mechanism | Patented lateral-release safety door with dual-stage explosion protection (Patent No.: ZL 200420032536) |
| Stirring | 360° reversible turntable |
| Reaction Vessel Capacity | 10–1500 mL (standard 500 mL) |
| Control Options | A-type (laptop-based software with real-time T/P curve monitoring, unlimited method storage) |
Overview
The MICHEM MD Series Microwave Digestion and Extraction System is a high-performance, CE-compliant benchtop instrument engineered for rapid, reproducible, and secure sample preparation in analytical laboratories. Based on the principle of microwave-assisted acid digestion—where targeted dielectric heating induces rapid molecular agitation within sealed reaction vessels—the system accelerates oxidative decomposition of organic matrices and dissolution of inorganic lattices under controlled temperature and pressure. Unlike conventional hotplate or block digesters, the MD Series leverages 2450 MHz monomode microwave energy coupled with a 45 L reinforced cavity to ensure uniform field distribution and scalable throughput. Its design complies with ISO/IEC 17025 requirements for method validation and supports GLP/GMP-aligned workflows through full audit-trail-capable software (A-type configuration). The system was originally developed under China’s National 10th Five-Year Science & Technology Key Project and has been validated in procurement tenders by the Chinese Academy of Sciences and Ministry of Education.
Key Features
- Patented lateral-release safety door with dual-stage pressure relief, certified to withstand transient overpressure events without rupture or uncontrolled venting.
- 45 L industrial-grade cavity constructed from thick-walled stainless steel and internally coated with Dupont PFA—a fluoropolymer offering exceptional resistance to aqua regia, hydrofluoric acid, and organic solvents at temperatures up to 300 °C.
- PID-controlled 1200 W magnetron delivering continuous, stepless power modulation (0–100%) for precise thermal ramping and isothermal hold stability.
- Dual-mode agitation system: electromagnetic stirring (for low-viscosity solutions) and mechanical rotating turntable (for heterogeneous slurries or solid residues), both adjustable from 0 to 5000 rad/min.
- High-integrity vessel architecture: outer PEEK vessels rated to 10 MPa burst pressure; inner TFM liners chemically inert across pH 0–14 and thermally stable to 300 °C.
- Real-time, synchronized monitoring of temperature and pressure across all vessels via fiber-optic and piezoresistive sensors—no cross-talk or signal drift.
- Compliance with IEC 61000-4-3 (EMC) and GB 4706.21 (microwave appliance safety), with measured leakage <0.3 mW/cm²—well below the international limit of 5 mW/cm².
Sample Compatibility & Compliance
The MD Series accommodates diverse sample types—including soils, sediments, biological tissues, polymers, alloys, and pharmaceutical excipients—across volumetric ranges from 10 mL to 1500 mL. Its sealed-vessel configuration minimizes volatilization loss of As, Hg, Se, and other semi-volatile analytes, directly enhancing accuracy in ICP-OES and ICP-MS quantification. All digestion protocols align with ASTM D5511, EPA Method 3052, and ISO 11466 for trace metal analysis. For regulated environments, the A-type control system supports 21 CFR Part 11 compliance when deployed with electronic signatures, user access tiers, and immutable audit logs. Vessels meet ISO 15195 calibration traceability requirements for pressure and temperature transducers.
Software & Data Management
The A-type configuration includes dedicated Windows-based software enabling full method development, execution, and post-run analysis. Users define multi-step temperature/pressure ramps, set safety interlocks (e.g., auto-shutdown at 5.8 MPa), and assign unique IDs to each run. All raw sensor data—including time-stamped T/P curves, power profiles, and stir speed—are stored in encrypted SQLite databases with SHA-256 hashing. Export formats include CSV, PDF reports (with digital signature fields), and XML for LIMS integration. The software supports IQ/OQ documentation packages and includes built-in uncertainty propagation calculators for combined standard uncertainty estimation per GUM (JCGM 100:2008).
Applications
- Environmental testing: heavy metal extraction from EPA SW-846 compliant soil and sludge samples prior to ICP-MS analysis.
- Clinical & forensic toxicology: complete digestion of hair, bone, and tissue for Cd, Pb, and Ni quantification per CLIA guidelines.
- Geochemical research: refractory mineral dissolution (e.g., zircon, monazite) using HF/HNO₃ mixtures at >220 °C and 5 MPa.
- Materials science: leaching of catalysts, battery cathodes, and nanocomposites for elemental release profiling.
- Food safety: total arsenic speciation support via quantitative recovery of As(III), As(V), MMA, and DMA after alkaline peroxide digestion.
FAQ
What safety certifications does the MD Series hold?
The system conforms to IEC 61000-4-3 (EMC immunity), IEC 60335-2-90 (microwave appliance safety), and GB 4706.21-2008. Third-party test reports verify compliance with EN 61000-6-3 and EN 61000-6-4.
Can the system be integrated into an automated laboratory workflow?
Yes—via RS-232 and Ethernet ports, the A-type controller supports Modbus TCP and OPC UA protocols for bidirectional communication with LIS/LIMS and robotic sample handlers.
Is method transfer possible between MD Series instruments?
All A-type systems use identical firmware and calibration constants. Method files (.mdf) are portable across units; inter-unit RSD for replicate digestions is ≤2.3% (n=6, CRM NIST 1643e).
What maintenance is required for long-term reliability?
Annual verification of pressure transducer linearity (per ISO 9001 clause 7.1.5.2) and cavity coating integrity inspection are recommended. Magnetron lifetime exceeds 5000 h under normal load conditions.
