This document discusses thermo-analytical techniques, specifically thermogravimetric analysis (TGA). It begins with an introduction to thermo-analytical methods and defines the difference between these methods and traditional analytical techniques. TGA is then explained in more detail, including the principles behind how it works, instrumentation involved consisting of a thermo-balance, furnace, and recording device, and factors that can affect TGA results such as sample characteristics and instrumental factors. Applications of TGA include stability studies, oxidation reactions, and pharmacokinetics studies.

1. THERMO-ANALYTICAL
TECHNIQUES
Presented by,
Miss. Sanmati Dilip Shete.
M . Pharm first year ,
Department Of Quality Assurance
Rajarambapu college of Pharmacy, kasegaon
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2. INTRODUCTION
 Thermo-analytical methods occupy a prominent
position.
 There are many analytical methods wherein use of
thermal coefficient involved
 They do not provide analytical information
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3. DIFFERENCE BETWEEN THERMO-ANALYTICAL
TECHNIQUES ANDANALYTICALTECHNIQUES
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 Thermo-analytical
techniques
In this method the effect of
temperature on compound
has been studied .
e. g:- TGA, DSC, DTA.
 Analytical techniques
This technique used to
determine concentration of
chemical compound or
chemical element.
e. g:- chromatography,
titration

4. CLASSIFICATION
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Name Property measured Apparatus
involved
Thermogravimetry
analysis(TGA)
Change in weight Thermo - balance
Derivative
thermogravimetric
analysis(DTA)
Rate of exchange of
weight
Thermo-balance
Differential thermal
analysis (DTA)
Heat absorbed or
evolved
DTA apparatus
Thermometers
titration
change in
temperature
Titration colorimeter

5. TGA
 TGA means thermogravimetric analysis.
 In gravimetric analysis, ignition or heating of a
precipitate or residue is carried out on a burner or in
oven at fixed temperature .(100º-200ºC)
 This method, though satisfactory in determining the
final change at the highest temperature
 This method not give any idea of the intermediate
formed or obtained at varying temperature of flame
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6. PRINCIPLE:
This can be illustrated by taking a
hypothetical compound XCO32H2O
and heating it in a linearly programed
furnace and recording the loss in
weight by thermo balance. When loss
in weight verses increasing
temperature plotted the graph will
obtained as follow :
It will be evident that at point A their is
loss water molecule
At point B their is break obtained due
to loss of water.
At point C - loss in weight is negligible
At point D - formation of XCO and
removal of CO2
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7. At point D and E - process continue until the
decomposition of X-O into metalic X.
In TGA the curve recorded depends on the following
factors like rate of heating, the nature or type of
furnace, the atmosphere and nature of the sample.
Decomposition of the sample is greater at slower rate
of heating than faster rate
Nature of reaction depending upon whether
exothermic or endothermic
Nature and type of crucible may affect rate of evolved
volatile matter.
At point B their is break obtained due to loss
of water.
At point C - loss in weight is negligible
At point D - formation of XCO and removal of
CO2
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8. INSTRUMENTATION
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THERMO-GREVIMETRIC ANALYSIS
INSTRUMENT.

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BLOCKDIAGRAM
OF TGA

11.  Mainparts of the TGAare as follows:
1. Thermo-balance
2. Sample holder
3. Furnace
4. Programmer device
5. Recording device
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12. 1. Balance:- Features are as follows
Reproducibility, Accuracy, sensitivity, toughness,
Characteristics
 It could cover wide range of temperature
 It should have high degree of mechanical rigidity and
electronic stability
 It should capable of recording changes in weight rapidly,
accurately and continuously as a function of temperature
and time
 The heating rate should be linear
Recording Thermo-balance are of 2 types
1) deflection type
a. Beam type :- In which conversion of beam deflection is
recorded as a signal on photographic recorder
b. Helical type :- involve use spring which contracts and
elogates depending on change in weight.
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13. 2. Sample holder :-
 Important part in TGA.
 Depending upon the nature of sample, it's weight and
quantity to be handled, different size and shape of
sample holders are employed
 Various Materials used for the construction of crucible
: glass, quartz, aluminum, stainless steel, platinum
etc.
Two types
a) Shallow pans
b) Deep crucible
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14. 3. Furnace :-
 These are made from high quality metal and vary in
shape and size
 Temperature :-1000º-2000ºC or by temperature control
panel
 Linear and fixed temperature maintained by use of
thermocouples
4 . Furnace temperature programmer :-
These controls gradual rise in temperature at a fixed rate
Device has course and fine control kinds which maintain
the temperature
5.Recorder :-
Having strip and pen mechanism w.
Electrical supply duly amplified is fed to recorder chart
Speed variable.
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15. APPLICATION
1)Stability studies
2)Oxidation and Combustion reaction
3) Combined Operation [ TGA with mass
spectroscopy]
4)Pharmacokinetics Studies
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16. FACTORS AFFECTINGTHERMO-
GRAVIMETRIC RESULTS
1. Instrumental factor.
2. Characteristics of sample.
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17. 1)Instrumental factor :-
These include various aspects of instruments like
furnace heating, recording of changes on chart, furnace
atmosphere, sample holder and its geometry means
deep crucible and shallow pan.
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18. 2)Characteristics of Sample :-
Important factors about the sample are:
Wt. Of sample
Particle size of sample
Nature of evolved gas
Thermal conductivity of sample
Heat of decomposition of the reaction
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