Merck Supelco® 33318-U Compact Modular Dry Bath Heater (Ambient to 150°C)

Overview

The Merck Supelco® 33318-U Compact Modular Dry Bath Heater is an engineered thermal platform designed for precise, reproducible conductive heating of samples in sealed containers without direct contact with liquid media. Operating on resistive heating principles, the unit delivers uniform thermal energy through high-conductivity anodized aluminum heating blocks, minimizing convective drift and ensuring minimal temperature gradient across sample positions. Its dual-range analog control system enables stable operation from ambient temperature up to 150°C—optimized for applications requiring controlled ramping, sustained incubation, or endpoint thermal activation. Unlike water baths, this dry bath eliminates contamination risk, evaporation artifacts, and maintenance overhead associated with fluid-based systems, making it especially suitable for molecular biology, clinical diagnostics, and quality control workflows where sample integrity and traceability are critical.

Key Features

• Compact footprint (31.5 × 20.3 × 8.9 cm) optimized for crowded benchtop environments without compromising thermal performance
• Dual-range analog temperature control: low range (ambient to 100°C) for sensitive biological assays; high range (75–150°C) for melting point determination, solvent evaporation, or enzyme denaturation studies
• ±0.1°C temperature stability and uniformity at 37°C—validated per ISO/IEC 17025-compliant calibration protocols—ensuring repeatability across shifts and operators
• Interchangeable modular heating blocks fabricated from anodized aluminum, providing rapid thermal response, corrosion resistance, and long-term dimensional stability under repeated thermal cycling
• Integrated thermometer well in each block enables real-time verification of block surface temperature using external calibrated probes—supporting GLP/GMP documentation requirements
• Universal power input (120 V / 230 V, auto-sensing 110 W) with CE, UL, and RoHS compliance for global laboratory deployment

Sample Compatibility & Compliance

The 33318-U accommodates a broad spectrum of standard labware via dedicated, user-replaceable blocks—including 0.2 mL and 0.5 mL PCR tubes, 1.5 mL and 2.0 mL microcentrifuge tubes, 4–20 mL glass or plastic vials, 96-well microplates (flat-bottom and U/V-bottom), and PCR strip formats. Each block is precision-machined to ensure consistent well depth, diameter tolerance (< ±0.05 mm), and thermal mass distribution—critical for inter-sample comparability in quantitative assays. The device meets ASTM E2251-22 for laboratory dry block heater performance verification and supports alignment with USP Analytical Instrument Qualification guidelines when deployed in regulated environments. All blocks are autoclavable (121°C, 20 min) and compatible with common organic solvents used in extraction or derivatization workflows.

Software & Data Management

This analog-controlled heater does not incorporate embedded digital interfaces or proprietary software. However, its design facilitates integration into validated instrument networks via external data loggers compliant with FDA 21 CFR Part 11 (e.g., certified thermocouple-based recorders with electronic signatures and audit trails). The integrated thermometer well allows continuous monitoring and recording of block temperature against reference standards, enabling full traceability for IQ/OQ/PQ documentation. Laboratories implementing paperless QC systems may pair the unit with LIMS-integrated environmental monitoring platforms using 4–20 mA or RS-485 signal adapters (sold separately).

Applications

• Enzyme kinetics and immunoassay incubation (e.g., ELISA, lateral flow activation)
• PCR tube pre-heating and post-amplification hold steps
• DNA/RNA hybridization and probe annealing protocols
• Melting point analysis of polymers, pharmaceutical excipients, and small molecules
• Solvent removal from concentrated extracts prior to GC or LC injection
• Standardization of viscosity reference materials at elevated temperatures
• Calibration of thermistor-based sensors and RTD probes

FAQ

Are heating blocks included with the 33318-U unit?
No—blocks are sold separately to allow users to configure the system for specific vessel geometries and throughput requirements.
Can the heater be used for sterilization purposes?
It is not validated for sterilization (e.g., 121°C/15 psi steam cycles); however, individual aluminum blocks may be autoclaved independently per manufacturer specifications.
Does the unit support programmable ramp/soak profiles?
No—it features manual analog control only. For time-temperature profiling, external programmable controllers or data loggers must be employed.
What safety certifications apply to this device?
The unit carries UL 61010-1 and IEC 61010-1 certification for electrical safety in laboratory environments, as well as CE marking for EMC and low-voltage directive compliance.
Is temperature calibration traceable to NIST standards?
Yes—when used with a NIST-traceable reference thermometer inserted into the block’s thermometer well, the system supports documented calibration per ISO/IEC 17025 Clause 6.5.