Thermogravimetric Analysis Medical Presentation

Thermogravimetric analysis PowerPoint Presentation

DOWNLOAD MEDICAL POWERPOINT PRESENTATION

About This Presentation

Description : Download Free Thermogravimetric analysis medical powerpoint (ppt) presentation for your medical ppt presentation

Tags : Pharmaceutical analysis

Published on : Jan 13, 2018 | Views : 4845 | Downloads : 54

Shareable Url :

Embed Code :

Comment

Transcript

Slide 1-

Welcome you all TO THE WORLD OF TGA
Slide 2-

PRESENTED BY S.MATHIVANAN. M.PHARM-1st YEAR DEPARTMENT OF PHARMACEUTICS
Slide 3-

Outline of this seminar Definition of thermal analysis What is thermal analysis and its types Thermogravimetric analysis TGA Theory and their types Instrumentation of TGA Methodology Factors affecting thermogravimetry results TGA applications.
Slide 4-

Thermal analysis DEFINITION: TA is a group of techniques that study the properties of materials as they change with temperature. In practice TA gives properties like enthalpy, thermal capacity, mass changes and the coefficient of heat expansion. Solid state chemistry uses TA for studying reactions in the solid state, thermal degradation reaction, phase transitions and phase diagrams.
Slide 5-

Introduction Thermal analysis is defined as “series of techniques for measuring the temperature dependency of a physical property of a certain substance while varying the temperature of the substance according to a specific program.” Physical properties include mass, temperature, enthalpy, dimension, dynamic characteristics, and others, and depending on the physical properties to be measured, the techniques of thermal analysis.
Slide 6-

Cont… Conventionally thermal analysis has been mainly employed in measurements for research and development, but in recent times it is used in many practical applications, as the testing standards on the basis of thermal analysis have been established, for example, in quality control in the production field, process control, and material acceptance inspection. It is also applied in wide fields, including polymer, glass, ceramics, metal, explosives, semiconductors, medicines, and foods.
Slide 7-

Basic principles of Thermal analysis
Slide 8-

ppt slide no 8 content not found
Slide 9-

THERMOGRAVIMETRIC ANALYSIS (TGA) Often Different properties are measured at the same time TGA-DTA, TGA-DSC, TGA-EGA (TGA-MS, TGA-FTIR)
Slide 10-

TGA Measurement changes in weight in relation to changes in temperature. THEORY: A large number of chemical substance invariably decompose upon heating, and this of heating a sample to observe weight changes is the underlying principle of thermo gravimetric analysis(TGA).
Slide 11-

Cont… The measured weight loss curve gives information on: Change in sample composition Thermal stability Kinetic parameters for chemical reaction in the sample A derivation weight loss curve can be used to tell the point at which weight loss is most apparent.
Slide 12-

ppt slide no 12 content not found
Slide 13-

Phenomenon causing mass change
Slide 14-

Types of TGA DYNAMIC TGA Sample is subjected to condition of continuous increase in temperature that is invariably found to be linear with time. STATIC TGA (Iso thermal) Sample is maintained at a constant temperature for a period of time during which any changes in weight observed carefully
Slide 15-

Types of TGA based on loading sample
Slide 16-

Instrumentation
Slide 17-

Instrumentation A high precision balance Sample holder A furnace Furnace programmer(controller) A recording device
Slide 18-

Balance
Slide 19-

Null point type It makes use of an appropriate sensing- element which aptly detects any slightest deviation of the balance beam. It provides the application of a restoring forces, directly proportional to the change in weight, thereby returning the beam to its original null-point. The restoring force is subsequently recorded either directly or with the aid of a transducer.
Slide 20-

Deflection type It is essentially based on either a conventional analytical balanced consisting of: Beam type: Conversion of beam deflection Helical spring type: Elongation or contraction of the spring with weight changes. Cantilever beam type: One end of the beam is fixed and the other end, on which the sample is placed, is free to undergo deflection. Torsion wire type: The wire is firmly fixed at either or both ends so that the deflection of the beam are proportional to weight changes.
Slide 21-

Ideal properties of balance Its accuracy, sensitivity, reproducibility and capacity should be similar to analytical balance It should have a high degree of mechanical and electrical stability It should have a rapid response to weight changes.
Slide 22-

Sample holder This is most important in accurate TGA Depending upon the nature of sample, its weight and quantity to be handled, different size and shapes of sample holders known as crucibles are employed These are constructed from various materials like glass, quartz, aluminum, stainless steels, platinum etc; These generally are of 2 types, Shallow pan for holding samples which eliminates gas, vapours of volatile matter by diffusion during heating Deep crucible for general purpose.
Slide 23-

ppt slide no 23 content not found
Slide 24-

ppt slide no 24 content not found
Slide 25-

Furnace Must be designed in such a fashion so as to incorporate an appropriate smooth input there by maintaining either a fixed temperature (or) predetermined linear heating program (e.g.., 100c-6000c per hour (6c/min) Temperature control is achieved via a thermocouple mounted very close to the furnace –winding
Slide 26-

Maximum operational temperature may be obtained using different thermocouple as indicated below
Slide 27-

Furnace temperature programmer (controller) These are the controller which can provide gradual rise of temperature at a fixed rate. This device has a course and fine control knob through which desired temperature with respect to rate or time can be obtained. This controlling is done by increasing voltage through the heated element by motor driven variable transformer or by different thermocouples.
Slide 28-

Recorder The recording device must be such so as to Record both temperature and weight continuously and Make a definite periodic records of the time. One main advantage of these recorder is that can check the heating rate of the furnace for linearity.
Slide 29-

Measurement possibilities
Slide 30-

TGA Methodology Ex. Decomposition of calcium oxalate monohydrate Calcium oxalate monohydrate, a standard material often used to demonstrate TGA performance. Exhibits three weight losses with temperature in an inert atmosphere (e.g. N2). -H2O -CO -CO2 CaC2O4 • H2O CaC2O4 CaCO3 CaO
Slide 31-

ppt slide no 31 content not found
Slide 32-

STAGE 1: The water of hydration (or crystallization) from calcium oxalate monohydrate is lost which corresponds to 2.46 mg (12.3%) equivalent to 1 mole of H2O in temperature ranges 100-250 C. STAGE 2 : One mole of calcium mono oxide is evolved subsequently from calcium oxalate, corresponding to 3.84 mg (19.2%) in the temperature ranges 400-500 C. STAGE 3 : Finally, a mole of CO2 is evolved from calcium carbonate that corresponds to 6.02mg (30.1%) in temperature ranges 700-800 C.
Slide 33-

Factors affecting results Instrumental factor: These include various aspects of instrument like, Furnace heating (its temperature and rate) Recording of changes on charts (its speed) Furnace atmosphere (its rate of cooling and maintaining temperature), Sample holder and its geometry (decomposition of calcium carbonate carried out in inert nitrogen) Sensitivity of balance.
Slide 34-

Cont… Characteristics of sample: The important factors about the sample are Weight of sample (E.g. decomposition of calcium oxalate.) Particle size of sample (decomposition proceeds at higher temperature) Nature of evolved gas or volatile matter Thermal conductivity of sample. The heat of decomposition of the reaction. Compactness of the Sample (decomposes higher than the loose samples)
Slide 35-

Why TGA??
Slide 36-

ppt slide no 36 content not found
Slide 37-

TGA-DSC for Pseudo-polymorphism
Slide 38-

ppt slide no 38 content not found
Slide 39-

ppt slide no 39 content not found
Slide 40-

THANK YOU…!!!