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Melting point meter1/17/2024 ![]() ![]() With substances that decompose, a heating rate of 5 ☌/min should be applied. For highest accuracy and non-decomposing samples use 0.2 ☌/min. Pharmacopeias apply a constant heating rate of 1 ☌/min. Results depend strongly on the heating rate - the higher the heating rate the higher the observed melting point temperature. The heating ramp rate is the fixed rate of temperature rise between the start and stop temperatures for the heating ramp. Common formula to calculate the start temperature: Start Temperature = expected MP – (5 min * heating rate) b) Heating Ramp Rate At the start temperature the capillaries are introduced into the furnace, and the temperature starts to rise at the defined heating ramp rate. Up to the start temperature, the heating stand is rapidly preheated. Melting point determination starts at a predefined temperature close to the expected melting point. ![]() Correct selection of the start temperature, the end stop temperature and the heating ramp rate are necessary to prevent inaccuracies due to a heat increase in the sample that is incorrect of too fast: a) Start Temperature Generally the filled height should not exceed 3 mm.Īlong with proper sample preparation, the settings on the instrument are as well essential for the exact determination of the melting point. Step 4: The correct filling height can be checked with the engraved ruler on the capillary filling tool. The 'bouncing effect' causes tight packing of the substance and avoids the inclusion of air pockets. This action packs the sample tightly down into the bottom of the capillary. Step 3: The small amount of sample at the top of the capillaries is then moved down the capillary by releasing the grip and gently bouncing the capillaries on the table several times. Collecting a small sample portion from a mortar is easily done with the assistance of the tool. The capillary filling tool perfectly assists the filling as the empty capillaries are securely held in a peg-like grip. Step 2: Several capillaries are prepared simultaneously for measurement with a METTLER TOLEDO instrument. Then a small portion of sample is finely ground in a mortar. Step 1: First, the sample needs to be dried in a desiccator. Sample preparation process using METTLER TOLEDO melting point tools: Compared to other physical values the change in light transmission can easily be determined and can therefore be used for melting point detection. Last but not least, the optical properties birefringence reflection and light transmission change. Amongst these are the thermodynamic values, specific heat capacity, enthalpy, and rheological properties such as volume or viscosity. The melting temperature of a crystalline solid is thus an indicator for the stability of its lattice.Īt the melting point not only the aggregate state changes quite a lot of other physical characteristics also change significantly. The more energy is needed, the higher the melting point. The stronger the forces of attraction between the particles, the more energy is needed to overcome them. The crystalline structure is destroyed and the solid material melts. When the solid crystalline material is heated, the particles become more energetic and start to move more strongly, until finally the forces of attraction between them are no longer strong enough to hold them together. The particles within the lattice are held together by lattice forces. During the phase transition, the two physical phases of the material exist side-by-side.Ĭrystalline materials consist of fine particles that for a regular, 3-dimensional arrangement – a crystalline lattice. ![]() During the melting process, all of the energy added to the substance is consumed as heat of fusion, and the temperature remains constant (see diagram below). This phenomenon occurs when the substance is heated. It is the temperature at which the solid phase changes to the liquid phase. Melting point is a characteristic property of solid crystalline substance. User skills and knowledge (theory of applications, technologies, methods, tips and tricks).Time reduction quick adjustment and scalability of methods.Sustainable design (futureproof modular design long lasting).Shift to the next level measurement process (from manual to automated, or to on-line measurement automation).Reduction in operating costs Total cost of ownership Maintenance cost reduction.Productivity (released time from the team) Uptime Optimize processes.Preventive maintenance Minimize downtime.Connectivity Software solutions Data flow from one instrument to another. ![]()
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