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Key: test item, instrument name, total nonvolatile migration, gravimeter, moisture permeameter

Product

Water Bath Drying Constant Weight Analyzer

ERT-231 /331 /461 /691 -C
Focusing on packaging and material testing technology, we are committed to quality control in industries such as healthcare, pharmaceuticals, food, packaging, textiles, and new materials. Our products are widely used in enterprises, testing institutions, universities, and research institutes.

Category:

Constant Weight Analyzer

Water Bath Drying Constant Weight

Water Bath Constant‑Weight Analyzer for Total Migration & Loss on Drying

ERT‑C Series (Automated Evaporation‑Drying‑Weighing Workstation)

Overview

The LabStone ERT‑C Series is a fully automated workstation designed to replace the traditional, labor‑intensive workflow of water baths, drying ovens, desiccators, and analytical balances. It is engineered for high‑throughput total migration testing, non‑volatile residue determination, and loss on drying / moisture analysis across pharmaceuticals, food contact materials, and chemicals.

By integrating water‑bath evaporation, precision drying, low‑humidity cooling, and analytical weighing into a single system, the ERT‑C Series delivers regulatory‑grade constant‑weight results with minimal operator intervention.

Key Applications

Food Contact Materials

Total Migration Testing: Gravimetric determination of migrants from plastics, paper, and multilayer packaging into food simulants (aqueous, acidic, alcoholic, and fatty).
Screening of New Formulations: Rapid evaluation of resin and additive impacts on migration performance.

Pharmaceutical & Biopharma

Extractables & Leachables (E&L): Non‑volatile residue profiling of container‑closure systems.
Loss on Drying (LOD): Water content determination in APIs, excipients, and bulk drugs.
Packaging Safety: Compliance verification for elastomeric closures and flexible films.

Food & Beverage QC

Moisture Analysis: Grains, dairy powders, starches, and dehydrated products.
Total Solids / Dry Residue: Bottled water, beverages, and liquid ingredients.

Chemicals & Polymers

Evaporation Residue: Resins, solvents, and chemical intermediates.
Volatile Matter: Plastics, rubber, and synthetic polymers.

Working Principle

The ERT‑C Series executes a fully automated four‑stage constant‑weight cycle:

Water‑Bath Evaporation

Test portions are gently evaporated to near‑dryness in a controlled water bath (ambient to 100 °C). Indirect heating prevents bumping and thermal degradation.

High‑Temperature Drying

Vessels are transferred to a precision drying chamber (ambient to 140 °C) to remove residual moisture and volatile matter.

Low‑Humidity Cooling

Vessels are cooled in a patented chamber maintained at < 20% RH, preventing moisture reabsorption-an inherent weakness of manual desiccator methods.

Constant‑Temperature Weighing

A METTLER TOLEDO analytical balance (0.1 mg readability) weighs the vessels. The system repeats the dry–cool–weigh cycle until constant weight (≤ 0.3 mg difference over two cycles) is achieved.

Compliance Standards

ISO 759 - Plastics - Determination of loss of volatile matter

ASTM D5404 / ASTM D6447 - Standard practices for moisture content by oven drying

USP <921> - Loss on Drying

Ph. Eur. 2.2.32 - Loss on Drying

EP 9.0 - Water, Purified

GB 31604.8 - Food contact materials - Determination of total migration

GB 5009.3 - National food safety standard - Determination of moisture in foods

GB 8538 - National food safety standard - Examination of drinking natural mineral waters

GB/T 9740 - Chemical reagents - General method for determination of evaporation residue

GB/T 2914 - Plastics - Determination of volatile matter

GB 5413.39 - Determination of insoluble dietary fiber in foods

GB/T 5750.4 / DZT 0064.9 / GB/T 14415 - Water and mineral analysis

ChP General Provisions - Constant‑weight requirement

ChP Part IV - Extractives determination method, Loss on Drying, Total Solids

ChP Part II - Purified Water

YBB 00342002 - Evaporation residue of pharmaceutical packaging

YBB 00132002 - Non‑volatile matter of pharmaceutical packaging

Key Features

Fully Automated 4‑in‑1 Workflow

Integrates evaporation, drying, cooling, and weighing into a single, unattended process.

Pharmacopoeia‑Grade Constant Weight

Achieves 0.3 mg constant weight within two drying cycles, fully aligned with USP, Ph. Eur., and ChP requirements.

Scalable High‑Throughput Configurations

Available with 23, 33, 46, or 69 workstations and 1–3 METTLER TOLEDO balances, supporting batch testing of large sample sets.

Patented Balance Protection

Thermal isolation, moisture‑proofing, and anti‑corrosion technologies protect the balance from heat, vapor, and corrosive residues.

Low‑Humidity Cooling Chamber

Maintains < 20% RH during cooling, eliminating moisture reabsorption errors common in manual methods.

Safe & Reliable Operation

Indirect heating, over‑temperature power‑off protection, and water‑level monitoring ensure safe handling of flammable solvents and acidic simulants.

Dual Test Modes

Constant‑Weight Mode (auto‑terminates at ≤ 0.3 mg) and Constant‑Time Mode (fixed drying duration).

GMP‑Ready (Optional)

Optional Computerized System Module provides user management, electronic signatures, and audit trails compliant with 21 CFR Part 11 and NMPA GMP.

High‑Efficiency Solvent Recovery (Optional)

Captures up to 95% of evaporated solvents (ethanol, acetic acid), reducing waste disposal costs and VOC emissions.

Technical Specifications

Name	Parameter		Name		Parameter
Constant Weighting Error	0.3 mg （2 heating cycles）		Residue Range		0～80 g
Balance Range	210 g		Balance resolution		0.1 mg
Temperature Error	0.5 ℃		Evaporating Temperature		RT ～100 ℃
Drying Temperature	RT～140 ℃		Weighing Temperature		RT～80 ℃
Evaporite Mode	Water bath		Weighing humidity		＜20%
Evaporating utensil capacity	100 mL(Optional: 50, 200 mL)		Connect Pipe		Φ8 mm
Air Pressure	>0.3 MPa		Solvent Recovery Rate		95%
Power Supply	AC220V /110V ;50/60Hz
Model	Model
	ERT-231-C	ERT-331-C		ERT-462-C		ERT-693-C
Specimen Count	23	33		46		69
Balance Count	1	1		2		3
Size (L×B×H) mm	1300x870x1160 mm
Net Weight	~170kg	~175kg		~180kg		~185kg
Power Consumption	<10,000 W

Standard Configuration

Main testing unit (host)

Drying system

Evaporating vessels (quantity per model)

Test computer with professional software

METTLER TOLEDO analytical balance (0.1 mg)

Valve suites

Optional Accessories

High‑Efficiency Solvent Recovery Device

0.01 mg Analytical Balance

GMP Computerized System Module

Alternative evaporating vessels (50 mL / 200 mL)

User‑Provided Items

Compressed air source (> 0.3 MPa)

Distilled water

Tap water

Frequently Asked Questions (FAQ)

Q1: How does the ERT‑C Series differ from a conventional drying oven?

A: Conventional ovens only dry samples. After drying, samples must be manually transferred to a desiccator and weighed-a process prone to moisture reabsorption and operator variability. The ERT‑C integrates evaporation, drying, low‑humidity cooling, and weighing into a single automated cycle, ensuring true constant‑weight compliance with pharmacopoeia requirements.

Q2: What does “0.3 mg constant weight” mean?

A: Pharmacopoeias define constant weight as successive weighings differing by no more than 0.3 mg. The ERT‑C automatically repeats the dry–cool–weigh cycle until this criterion is met, eliminating subjective judgment and ensuring regulatory compliance.

Q3: Can this instrument perform total migration testing with alcoholic simulants?

A: Yes. The ERT‑C is fully compatible with aqueous and alcoholic simulants. For ethanol‑based methods, the optional solvent recovery device is strongly recommended to manage VOC emissions and reduce hazardous waste.

Q4: Why is low‑humidity cooling important?

A: After drying, hot residues rapidly reabsorb moisture from ambient air. The ERT‑C cools samples in a < 20% RH chamber, stabilizing the residue mass before weighing-critical for trace‑level residue and moisture determinations.

Q5: How do I choose the right model?

A: Selection depends on daily sample throughput:

ERT‑231‑C: Small QC labs (~20 samples/day)

ERT‑331‑C: Medium‑scale testing

ERT‑462‑C: High‑volume QC and contract labs

ERT‑693‑C: Large contract research organizations and national testing institutes

Q6: What is the difference between the ERT‑C Series and the IRT Series?

A: The ERT‑C Series is designed for low‑temperature applications (≤ 140 °C): total migration, non‑volatile residue, and loss on drying. The IRT Series is designed for high‑temperature ashing (up to 1000 °C): ignition residue, ash content, and loss on ignition. They are complementary systems for different gravimetric methods.

Functions
Constant weight tests for loss on drying, non - volatile substances, residue quantity, total migration, volatile substances, moisture content, soluble and insoluble quantities.
It can replace water baths, drying ovens and balances to achieve constant weight .

Principle
Water bath evaporation; high temperature drying; drying and cooling; constant temperature weighing.
Standards:
Constant weighting requirement in Chinese Pharmacopoeia, Extractives Determination Method" in Part Four of the Chinese Pharmacopoeia、Loss on Drying Determination Method、Total Solids Determination Method、USP40-NF35<921>、YBB 00342002、YBB00132002、GB 31604.8、GB5009.3、GB 8538、DZT0064.9、GBT14415、GBT5750.4、GB/T 9740、GB/T2914、GB5413.39、ISO 759、"Purified Water" in Part Two of the Chinese Pharmacopoeia、EP9.0 WATER, PURIFIED
Features
- Complies with national standards and features a fully automated four-process system: water bath, drying, cooling, and weighing.
- Precise and efficient: Achieves 0.3mg constant weight with just 2 drying cycles. Available with 12、18, 23, 33, 46, or 69 workstations.
- Safe: Indirect heating design to prevent combustion and explosion. Equipped with over temperature power off protection and water level protection.
- Compact: Water bath chamber, drying oven, cooling unit and weighing balance are integrated into one unit, footprint reduction.
- Features patented: heat insulation, moisture proof, and anti-corrosion technology for the balance, ensuring its stability and long service life.
- Digitally set test parameters, fully automated operation without manual intervention. Offers two test modes: constant weight and constant time.
- Equipped with METTLER TOLEDO balance.
- Software: Provides graphical, full process and all element monitoring, along with multiple report formats.
- Optional: GMP "Computerized System" functional module.
- Optional: High - efficiency solvent recovery device.

Specification

Name	Parameter		Name		Parameter
Constant Weighting Error	0.3 mg （2 heating cycles）		Residue Range		0～80 g
Balance Range	210 g		Balance resolution		0.1 mg
Temperature Error	0.5 ℃		Evaporating Temperature		Room Temperature ～100 ℃
Drying Temperature	Room Temperature～140 ℃		Weighing Temperature		room～80 ℃
Evaporite Mode	Water bath		Weighing humidity		＜20%
Evaporating utensil capacity	100 mL (Optional: 50, 200 mL)		Connect Pipe		Φ8 mm
Air Pressure	>0.3 MPa		Solvent Recovery Rate		95% (Optional: Solvent Recovery Machine)
Power Supply	AC220V /110V ;50/60Hz
Model	Model
	ERT-231-C	ERT-331-C		ERT-462-C		ERT-693-C
Specimen Count	23	33		46		69
Balance Count	1	1		2		3
Size (L×B×H) mm	1300x870x1160 mm
Net Weight	~170kg	~175kg		~180kg		~185kg
Power Consumption	<10,000 W

Configuration: Principal Machine, Dryer Machine, Evaporating Utensil, Computer, Professional software, Valve Suits.
Optional: Solvent Recovery Machine、0.01mg balance.
Self-provided: Compressed air、Distilled water, tap water..

Keywords:

Ignition Residue and Ash Constant Weight Analyzer

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