Name: Melting Point Tube
Brand: RichTech

Specifications

Melting Point Tube · Specifications

The following is the standard specification. Custom sizes are available upon request.

Size (mm)	Tube Shape	Approx. Wall Thickness (mm)	Packaging (pcs/case)	Material	Recommended Media
150×24	Triangular	1.5 – 2.0	100	Borosilicate 3.3	Silicone Oil / Glycerol

* Size is a nominal value. Actual dimensions may vary slightly.
* Custom sizes and special specifications available upon request. Bulk pricing available.
* Recommended for use with melting point capillaries (one-end sealed) and melting point apparatus.

Accessory Recommendations: Pair with melting point capillaries (0.9–1.1mm internal diameter, approximately 100mm length) and methyl silicone oil (100–500 cSt viscosity) or glycerol as the heating medium for optimal performance.

Product Description

The melting point tube is the essential vessel for melting point determination in analytical and quality control laboratories. Manufactured from high-quality borosilicate glass 3.3, the triangular tube body provides stable positioning in the heating bath of melting point apparatuses, while the high clarity enables clear observation of the melting process of samples contained in capillary tubes. RichTech melting point tubes feature uniform wall thickness, excellent heat resistance, and high transparency — ensuring accurate, reproducible melting point results.

Key Features

Borosilicate Glass 3.3: ISO 3585 compliant · Low thermal expansion · Thermal shock resistance up to 280°C · Chemically resistant
Triangular Tube Design: Stable positioning in heating bath · Flat surfaces for clear observation
Superior Heat Resistance: Withstands repeated heating and cooling cycles without cracking
High Clarity: High-purity glass enables clear viewing of sample melting through capillary tubes
Uniform Wall Thickness: Even heat distribution ensures accurate temperature readings
Standard Size: 150×24mm — compatible with all major melting point apparatus
Reusable: Durable construction for repeated use after proper cleaning

Principle of Operation: The melting point tube serves as the vessel for the heating medium (typically silicone oil or glycerol). A capillary tube containing the sample is immersed in the heating medium, and the temperature at which the sample begins to melt and completely melts is observed. The triangular design prevents rolling in the heating bath, ensuring stable and reliable measurements.

Quality Assurance

Each melting point tube undergoes rigorous dimensional inspection, wall thickness uniformity testing, and heat resistance verification. Our products meet laboratory glassware quality standards, providing reliable performance for melting point determinations.

Note: Melting point tubes are heating vessels — always inspect for cracks or chips before use. Heat slowly (typically 1–2°C/min) to avoid splashing or thermal shock. Replace heating medium regularly to maintain clarity for optimal observation.

Applications

Typical Application Areas

Pharmaceutical Quality Control

API melting point determination (ChP 0612) · Excipient melting point testing

Chemical R&D

Organic compound melting point determination · New compound characterization · Purity assessment

Food Industry

Food additive melting point testing · Oils and fats melting point analysis

Materials Science

Polymer melting point determination · Thermal characterization of crystalline materials

Education

Organic chemistry laboratory melting point experiments · Compound purity identification

Compliance & Standards

ChP 0612 — Melting Point Determination Method (Chinese Pharmacopoeia)
ChP 0612 — Melting Point Determination
EP 2.2.14 — Melting Point — Capillary Method
GB/T 617 — Chemical Reagent — General Method for Melting Point Determination
ISO 1392 — Petroleum products — Determination of melting point of waxes

Tip: The melting point tube is a core component of the melting point determination system, working together with capillaries, thermometers, and melting point apparatus. For best results, pair with RichTech capillaries and thermometers for a complete melting point determination solution.

Melting Point Tube Operation Guide

03

Preparation Before Use

Inspect for cracks, chips, or other defects
Wash with mild detergent and soft brush — rinse 3 times with distilled water — dry before use
Prepare heating medium (silicone oil or glycerol) — fill the tube to approximately 2/3 capacity
Prepare capillary tubes containing the sample (sample should be finely powdered and dried)

04

Melting Point Determination Procedure

Securely mount the melting point tube vertically in the melting point apparatus or oil bath
Immerse the capillary tube into the heating medium with the sample end downward, aligned with the thermometer bulb
Heat slowly: Maintain a heating rate of 1–2°C/min (reduce to 0.5–1°C/min near the expected melting point)
Observe and record: Record the onset temperature (first appearance of liquid) and complete melting temperature (sample fully liquefied)
Run each sample in duplicate or triplicate and calculate the average

05

Post-Determination Handling

Stop heating and allow the tube to cool naturally to room temperature
Dispose of capillary tubes safely, drain heating medium if cloudy or degraded
Clean the tube promptly to prevent residue build-up

06

Cleaning & Maintenance

Drain heating medium while still warm and wipe the interior with a soft cloth
Routine cleaning: Mild detergent + soft brush — rinse 3 times with distilled water
Stubborn residues: Dissolve with acetone or ethanol followed by detergent cleaning
Air dry inverted or place in oven at 60°C
Store separately or in dedicated racks to avoid impact damage

Care & Notes

Show care & notes

Safety Precautions

Inspect for cracks or scratches before use — damaged tubes may break during heating
When determining samples that sublimate or decompose, work in a fume hood
Heated tubes are extremely hot — allow to cool before handling

Do not

Always use melting point apparatus or oil baths — never heat directly over an open flame
Consider the flash point and boiling point of heating media — avoid exceeding safe temperatures