Overall Migration & Non-Volatile Residue Constant Weight Tester
Automates the full water-bath evaporation, drying, cooling and constant-temperature weighing cycle in one cabinet — evaporation residue to constant weight at ≤0.3 mg, unattended.
Purpose | What it does for you
Determines total migration, non-volatile substances, evaporation residue, loss on drying, moisture content, total solids, solid waste and leachables in food-contact materials and pharmaceutical packaging. It replaces the water bath, drying oven, desiccator and repeated manual weighing: load the samples once and the instrument runs water-bath evaporation, drying, cooling and constant-temperature weighing automatically — including the labour-intensive repeat dry-cool-weigh loop. Labs compress a 2–3 day, multi-operator task into a one-button run while eliminating transfer contamination and manual weighing error.
Key Features
- Fully automated four-stage cycle (bath, drying, cooling, weighing) with no manual intervention
- 0.3 mg constant weight reached in only two drying cycles — far faster than conventional ovens
- Indirect heating for flame/explosion safety, plus over-temperature cut-off and water-level protection
- Patented heat-insulation, moisture-proof and anti-corrosion protection for the balance
- 12 / 18 / 23 / 33 / 46 / 69 workstations to match your throughput
- Optional solvent recovery unit (95% recovery) cuts VOC emissions and reagent consumption
- Graphical full-process monitoring with multiple report formats; optional GMP Computerized System module
Operating Principle
Four-stage process: water-bath evaporation → high-temperature drying → controlled cooling → constant-temperature weighing. Samples in evaporating dishes are evaporated to near dryness on a thermostatic water bath, dried on a heated aluminium plate, cooled to the set temperature, then weighed inside the same cabinet by a built-in METTLER TOLEDO analytical balance. The system repeats the dry–cool–weigh loop automatically until the difference between two consecutive weighings is below 0.3 mg, then calculates and reports the result.
Technical Specifications
| Constant Weight Error | 0.3 mg (2 drying cycles) |
|---|---|
| Residue Range | 0~80 g |
| Balance Range | 220 g |
| Balance Resolution | 0.1 mg (0.01 mg optional) |
| Temperature Error | ±0.5 ℃ |
| Evaporating Temperature | RT~100 ℃ |
| Drying Temperature | RT~150 ℃ |
| Weighing Temperature | RT~80 ℃ |
| Weighing Humidity | <20 % |
| Compressed Air Pressure | >0.3 MPa |
| Power Supply | AC 220/110 V ±10%,50/60 Hz |
| Power | <10,000 W |
Note: Due to continuous product iteration and varying application conditions, the technical parameters on this page are typical reference values and are not to be used as acceptance criteria. For tender and customized projects, the product model, configuration and specifications are subject to the mutually confirmed technical agreement and the actual delivered product. For parameter matching tailored to your specific project, please contact us.
Models & Configuration
| Model | ERT-121-C | ERT-181-C | ERT-231-C | ERT-331-C | ERT-462-C | ERT-693-C |
|---|---|---|---|---|---|---|
| Specimen Count | 12 | 18 | 23 | 33 | 46 | 69 |
| Balance Count | 1 | 1 | 1 | 1 | 2 | 3 |
| Net Weight | ~150 kg | ~154 kg | ~290 kg | ~308 kg | ~315 kg | ~325 kg |
Standard Configuration
Main unit, cooling/dryer unit, evaporating dishes, computer, professional software and valve set. Optional: solvent recovery machine, 0.01 mg balance. User supplies compressed air, distilled water and tap water.
Application Scenarios
- Total migration compliance testing of food-contact materials (GB 31604.8)
- Non-volatile residue and extractables in pharmaceutical packaging (YBB 00342002 / YBB 00132002)
- Moisture, loss on drying and total solids in food (GB 5009.3, GB/T 14415)
- Extractives and evaporation residue of herbal drugs (Chinese Pharmacopoeia Part IV)
- Total dissolved solids, evaporation residue and solid-waste leachates (HJ 51-2024, GB/T 5750.4)
- Non-volatile residue of purified water (USP <921>, EP 9.0)
Compliance Standards
Industries Served
- Pharmaceutical & Biopharmaceutical
- Food & Condiments
- Packaging & Printing
- Traditional Chinese Medicine & Herbal
- Environmental Monitoring & Solid Waste
- Public Health CDC & Customs Technical Centers
- Third-Party & Government Testing Institutes
- Material R&D, Universities & Institutes
- Cosmetics & Personal Care
Frequently Asked Questions
Why does it reach 0.3 mg constant weight in only two drying cycles?
Because weighing happens at a controlled temperature inside the same sealed cabinet: after drying, the sample cools to the weighing setpoint without ever meeting ambient humidity, so the moisture re-uptake that forces extra cycles in a conventional workflow never occurs.
Can it handle simulants containing ethanol, n-hexane or other organic solvents?
Yes. Heating is indirect (water bath) rather than direct electric, combined with over-temperature cut-off and water-level protection — the design targets flammable organic systems. We recommend adding the solvent recovery unit (95% recovery) to reduce emissions and simplify waste handling.
Can dish capacity and workstation count be customised to our sample volume?
Yes. Dishes are 100 mL as standard (50 mL and 200 mL optional) and workstations range from 12 to 69. For unusual sample formats or throughput we can customise the chamber layout and rack to your URS.
Why is the constant-weight criterion set at 0.3 mg?
Pharmacopoeias and GB methods usually define constant weight as a difference of no more than 0.3 mg between two consecutive weighings (a few standards use 0.5 mg or 0.2 mg). The instrument judges at ≤0.3 mg by default, which covers most pharmacopoeia and food-contact methods; if your standard specifies another criterion, confirm applicability with an engineer before ordering.
Are evaporation residue, non-volatile matter and overall migration the same thing?
No. Overall migration is the total non-volatile substance transferred from a food-contact material under a specified simulant and contact condition; evaporation residue is the mass left after the soak or extract solution is taken to dryness; non-volatile matter refers specifically to the fraction that does not volatilise at that temperature. Their sample preparation and simulants differ, but all three end with evaporation, drying and constant-weight weighing, so one constant-weight tester serves them all.
Can loss on drying be reported directly as water content?
They are not equivalent. Loss on drying is everything the sample loses at the specified temperature — water, residual solvent and other volatile components; water content means H₂O specifically and is usually determined by Karl Fischer titration or a dedicated moisture analyser. The two figures approach each other only when water is the sole volatile present. A compliance report should state the method and conditions for each.
How do ignition residue, ash, acid-insoluble ash and loss on ignition differ?
The four differ in temperature, duration and preparation, but all end in the same high-temperature ignition, cooling and constant-weight weighing step, so one high-temperature instrument covers them. Ignition residue is the inorganic residue left after high-temperature ignition; ash is what remains after food, pharmaceutical or herbal material is ignited at a specified temperature; acid-insoluble ash treats the ash further with acid and keeps only the insoluble part, to reveal sand and other extraneous matter; loss on ignition (LOI) is the mass percentage lost by solid waste, building materials or minerals at high temperature.
Does LabStone support OEM/ODM and customised instruments?
Yes. Standard models ship as-is, while chamber count, specimen size, fixtures, temperature range and software modules (including the GMP Computerized System module) can be tailored to your SOP and URS. IQ/OQ/PQ validation documentation packages are available.
What is the typical lead time, and how is shipping handled?
Standard models usually ship in 4–8 weeks; customised builds depend on the agreed scope. Instruments are packed in export wooden cases and can move by sea, air or rail. We supply proforma invoice, packing list and certificate of origin (CO / Form E), and work under EXW, FOB, CIF or DAP terms.
How are installation, training and calibration handled after delivery?
We provide remote installation guidance, bilingual (Chinese/English) manuals and video training; on-site commissioning by our engineers is available. Users can self-calibrate with standard weights, reference films or calibrated leak standards, and third-party calibration certificates can be supplied.
What is the warranty, and how are spare parts supplied?
The instrument carries a 12-month warranty from acceptance plus lifetime maintenance support. Consumables (molecular sieve, desiccant, sealing grease, printer paper) are kept in long-term stock, and key components are international brands available worldwide. We respond to technical enquiries within 24 hours.
Do the instruments comply with ASTM, ISO and pharmacopoeia standards?
Yes. Every instrument lists its applicable standards on the specification page (ASTM, ISO, GB, YBB, Chinese Pharmacopoeia, USP, EP, JIS, DIN, TAPPI and more). The software outputs raw records and reports suitable for audit trails, with an optional GMP / FDA 21 CFR Part 11 compliance module.
Which languages does the software support, and can it integrate with a LIMS?
The software ships with Chinese and English interfaces; other languages can be added on request. Data export is available over RS232, USB, Ethernet or Wi-Fi, and reports can be exported to Excel, PDF or structured files for LIMS integration.