Chengmeng CM24TS/CM36TS Corrosion-Resistant Electrically Adjustable Water Bath Nitrogen Evaporator

Overview

The Chengmeng CM24TS and CM36TS Corrosion-Resistant Electrically Adjustable Water Bath Nitrogen Evaporators are precision-engineered instruments designed for gentle, reproducible solvent removal from multiple liquid samples under controlled thermal and gaseous conditions. Based on the principle of inert gas sweep-assisted evaporation—where nitrogen or filtered ambient air is directed tangentially across the surface of heated samples—the system accelerates solvent volatilization while minimizing analyte degradation, oxidation, or cross-contamination. Unlike dry-block or infrared evaporators, the water bath configuration ensures uniform, low-gradient heating (ambient +5°C to 99°C), critical for thermolabile compounds in environmental, pharmaceutical, food safety, and clinical toxicology applications. The instrument’s core architecture integrates a corrosion-inhibiting PTFE-coated circular bath, motorized vertical sample rack adjustment, and independently controllable gas delivery per position—enabling method flexibility across diverse sample matrices and container geometries.

Key Features

• Electrically driven vertical adjustment of the sample holder and gas manifold—enabling precise positioning of PTFE-coated needles (120 mm length, 18G, 4″) relative to liquid meniscus height across all 24 or 36 positions.
• PTFE-coated stainless steel construction throughout fluid-contact surfaces—including bath vessel, support disc, spring-loaded tube clamps, and gas distribution manifold—to ensure long-term resistance to HCl, HF, nitric acid, and alkaline digestates.
• Dual independent gas inlets with integrated pressure regulation (0.2 MPa max) allow seamless switching between high-purity nitrogen (for oxygen-sensitive analytes) and filtered compressed air (for robust matrices), reducing operational cost without compromising method integrity.
• Per-channel needle valves and calibrated rotameters enable fine-grained gas flow control (0–15 L/min total; typical consumption ~330 mL/min per sample), supporting optimization of evaporation rate versus analyte recovery.
• Circular 360° rotating sample platform improves ergonomics and accessibility—operators can load/unload tubes from the front without repositioning the unit inside fume hoods, while simultaneous rotation of both sample disc and gas manifold prevents positional bias and enhances reproducibility.
• PID-controlled digital LCD thermostat with programmable timer (0–9999 min), overtemperature cutoff, and auto-shutoff upon bath dry-out—meeting essential safety requirements for unattended overnight operation.
• Compatible with standard laboratory vessels: round-bottom test tubes (10–29 mm OD), centrifuge tubes, conical vials, and small-volume scintillation vials (1–50 mL capacity).

Sample Compatibility & Compliance

The CM24TS/CM36TS accommodates heterogeneous sample formats without adapter kits—its spring-tensioned tube holders self-adjust to outer diameters from 10 mm to 29 mm, eliminating slippage during gas sweep. All wetted components—including gas needles, tubing (SMC TUS fluoropolymer), bath liner, and valve bodies—are chemically inert per ASTM D543 and ISO 10993-5 standards. The system supports method validation per USP , EPA Method 505/525, and AOAC 995.12, and its deterministic temperature control (±0.5°C stability) and traceable gas flow calibration align with ISO/IEC 17025 clause 5.4.2 for equipment qualification. For regulated environments, the timer log and manual override records satisfy basic ALCOA+ data integrity expectations—though full 21 CFR Part 11 compliance requires integration with validated LIMS or ELN platforms.

Software & Data Management

The CM24TS/CM36TS operates via embedded firmware with no external PC dependency. All operational parameters—including setpoint temperature, elapsed time, remaining countdown, and real-time bath temperature—are displayed on a backlit LCD interface. While the instrument does not feature Ethernet or USB connectivity, it supports manual protocol documentation through timestamped operator logs. For labs requiring electronic record retention, the unit’s stable thermal profile and repeatable gas flow settings facilitate straightforward SOP integration into validated workflows. Optional RS-232 output (available on request) enables basic telemetry logging via third-party DAQ systems under controlled validation protocols.

Applications

• Pre-concentration of pesticide residues (e.g., organophosphates, pyrethroids) in aqueous extracts prior to GC-MS analysis per EPA 8270D.
• Post-digestion cleanup of heavy metals (As, Pb, Cd) in soil and biological tissues using hydrochloric or nitric acid media.
• Removal of acetonitrile or methanol from LC-MS/MS extracts of pharmaceuticals in plasma or urine—preserving labile glucuronide conjugates.
• Routine evaporation of volatile organic compounds (VOCs) in drinking water testing (EPA 524.2) where thermal decomposition must be avoided.
• High-throughput preparation of calibration standards and QC samples across clinical toxicology panels.

FAQ

Is the water bath volume sufficient for stable temperature control across all 36 positions?
Yes—the Φ400 × 200 mm internal bath volume (≈25 L) provides thermal mass adequate to maintain ±0.5°C uniformity at 99°C, verified per ASTM E2209 calibration procedures.
Can I use this instrument for acidic digestates from microwave-assisted digestion?
Yes—full PTFE coating on all contact surfaces, including the gas manifold and needle guides, ensures compatibility with 6 M HCl, 14 M HNO₃, and aqua regia up to 90°C.
What maintenance is required for long-term reliability?
Routine cleaning of the bath with deionized water and periodic inspection of PTFE needle integrity; no lubrication or recalibration is needed under normal use.
Does the system include a nitrogen generator or gas regulator?
No—external nitrogen supply (≥99.998% purity) and a dual-stage stainless steel regulator (0–0.4 MPa range) must be provided by the user.
How is height adjustment powered and controlled?
A brushless DC motor drives the vertical lift mechanism via a stainless steel lead screw; position is controlled via tactile buttons with incremental feedback on the LCD display.