DS MK-20 Refrigerated Metal Block Thermostat

Overview

The DS MK-20 Refrigerated Metal Block Thermostat is a precision-engineered dry-block thermal platform designed for laboratory applications requiring stable, rapid, and bidirectional temperature control—from sub-ambient cooling to high-temperature incubation. Unlike water baths, this metal bath eliminates contamination risks, evaporation losses, and maintenance overhead by using solid-state Peltier-based thermoelectric modules coupled with high-conductivity aluminum heating/cooling blocks. Its microprocessor-controlled architecture ensures repeatable thermal profiles across diverse sample formats, making it suitable for critical workflows including serum coagulation, DNA denaturation prior to PCR or electrophoresis, enzyme inactivation, and controlled sample storage. The device operates within a validated range of −10 °C to 100 °C, with typical stability of ±0.3 °C across the block surface at 40 °C—a performance benchmark aligned with ISO/IEC 17025-recommended thermal uniformity requirements for analytical instrumentation.

Key Features

• Bi-directional Peltier thermoelectric system enabling both precise heating and active refrigeration without external chillers or cryogens
• High-resolution 0.1 °C digital display with dual-parameter interface: simultaneous setpoint and real-time temperature readout, plus countdown timer
• Optimized thermal mass and airflow management ensure ≤5 min heating time from 20 °C to 100 °C and ≤30 min cooling from ambient to −30 °C (tested at ≤26 °C ambient)
• Modular aluminum block design supports 14 standardized interchangeable configurations—including 96-well PCR plates, 0.2 mL to 50 mL tube formats, and custom-machined wells—enabling full traceability and easy decontamination between runs
• Integrated safety architecture: independent over-temperature cutoff, self-diagnostic firmware with error-code reporting, and acoustic alarm for operational anomalies
• Compact footprint (270 × 190 × 170 mm) and low power draw (150 W max) support benchtop deployment in regulated environments such as QC labs operating under GLP or GMP frameworks

Sample Compatibility & Compliance

The MK-20 accommodates a broad spectrum of primary labware through its field-replaceable block system. Standardized modules include configurations for 0.2 mL PCR strips, 0.5–2.0 mL microcentrifuge tubes, 5–50 mL conical tubes, flat-bottom 96-well microplates, and rectangular reservoirs. All blocks are CNC-machined from anodized aluminum to ensure consistent thermal transfer, corrosion resistance, and compatibility with common sterilization methods (autoclaving, ethanol wiping, UV exposure). The instrument meets IEC 61010-1:2010 safety standards for laboratory electrical equipment and complies with electromagnetic compatibility (EMC) requirements per EN 61326-1. While not certified for FDA 21 CFR Part 11 compliance out-of-the-box, its programmable timer logs and temperature stability profile support audit-ready documentation when integrated into validated SOPs.

Software & Data Management

The MK-20 operates as a standalone instrument with no proprietary software dependency. All operational parameters—including temperature setpoint, hold duration, ramp rate (fixed), and alarm thresholds—are configured via intuitive front-panel controls. The LCD retains last-used settings after power cycling, minimizing reconfiguration effort. For laboratories requiring electronic recordkeeping, optional RS-232 or USB-to-serial adapters (sold separately) enable connection to LIMS or ELN systems. When interfaced, the unit transmits timestamped temperature readings at user-defined intervals (1–60 s), supporting ALCOA+ data integrity principles. Audit trail generation, however, must be implemented externally via connected software adhering to 21 CFR Part 11 requirements.

Applications

• Serum and plasma coagulation assays in clinical diagnostics and transfusion medicine
• Pre-PCR thermal denaturation of genomic DNA and cDNA templates
• Controlled enzymatic reaction quenching (e.g., restriction digests, ligations)
• Stabilized storage of temperature-sensitive reagents (antibodies, enzymes, oligonucleotides) during assay setup
• Calibration verification of pipettes and thermometers using NIST-traceable reference blocks
• Accelerated stability testing of formulations in pharmaceutical development (ICH Q1A)

FAQ

Does the MK-20 support gradient temperature programming?
No. The MK-20 maintains a single uniform temperature across the entire block surface; it does not offer multi-zone or gradient control.
Can the instrument be used for long-term incubation at 4 °C?
Yes—continuous operation at refrigerated temperatures (−10 °C to 10 °C) is supported, though ambient conditions should remain ≤26 °C for optimal cooling efficiency and compressor-free Peltier longevity.
Are replacement blocks supplied with calibration certificates?
Standard modules ship without individual calibration documentation; however, DS provides NIST-traceable factory calibration reports upon request for a nominal fee.
Is the unit compatible with ISO 15189-accredited medical laboratories?
Yes—when operated within specified environmental limits and included in a documented equipment qualification protocol (IQ/OQ/PQ), the MK-20 satisfies thermal performance criteria referenced in CLSI EP23-A and ISO 15189:2022 Annex A.3.2.
What maintenance is required for sustained accuracy?
Annual verification of temperature uniformity and accuracy using a calibrated reference thermometer (e.g., Fluke 1523/1524) is recommended; no internal lubrication or consumables are required.