I am attaching 2 articles which will help you to calculate %weight loss of molecules from Thermogravimetric Analysis TGA curve.

Check this paper

https://www.astm.org/DIGITAL_LIBRARY/JOURNALS/TESTEVAL/PAGES/JTE20140280.htm

Dear Olanrewaju,

Try to follow the following excel file, obtained from TGA instrument. Please see the last column showing wt. % calculation.

Thank you.

Dear Olanrewaju,

Step1: calculate molecular weight of your sample first,

Step2: now make possible calculation, such as water have 18 M.wt.

Step 3: divide that molecular wt from overall molecular mass and then multiple with 100. you will find nearly % shown on TGA graph. you will find your experimental calculated wt in %

For example: Molecult wt of ZnSO4.7H2O= 287.55

molecult wt of water: 18

total wt loss in first step: 6% (See your TGA curve)

Now : 18/287.55 = 0. 62.

0.62 * 100= 6%

It mean in first stem water molecule is loss.

Dear Adesoji A. Olanrewaju,

1. Establish the composition of complex by using various techniques such as XRD, icp-oes and chns.

2. Then by knowing the complex molecular weight, identify the region of weight loss on the tga thermogram or if you combine tga and dta thermograms in origin software you'll get exact idea that where the weight loss is taking place.

Adesoji .... Once you know the molecular weight of the compound you are studying, you may simply calculate the weight loss in terms of the molecular weight units. If the instruments expresses the results as (%) you can simply multiply the M.W. by the % loss. The result will give you the M.W. of the lost material> Example: we were analyzing a heterocyclic compound with a ring containing 3 nitrogen atoms. The calculation gave 28 in M.W. units. The lost portion was simply (N2). We we analyzed the other derivatives and the results were indicative of the lost nitrogen molecule from one molecule of the compound.... If you need further discussion I am available to support you

You may refer to:

Thermochimica Acta, 177 (1991) 329.

Thermoanalytical investigations of hetero-cyclic organic compounds. Part 5: thermal decomposition of some substituted n-phenyl-phthalamic acids.

Thermochim. Acta, 138 (1989) 13-20.

Thermoanalytical investigations on hetero-cyclic organic compounds: part 4: thermal decomposition of 1-benzyl, 2, 3-triazoloino-4, 5-n-phenyl-dicarboxiimides.

Thermochim. Acta, 79 (1984) 139.

Thermoanalytical investigations on heterocyclic organic compounds: part II: thermal decomposition of substituted 1,4-dihydro,2,4-dioxo-2h3,1-benzoxazine.

Thermochim. Acta, 70 (1983) 347-358.

weight loss (%) = (mi-mt/mi) *100

mi = initial mass

mt = final mass

i) For RG discussion on the thermal decomposition of sodium carbonate: https://www.researchgate.net/post/Thermal_decomposition_of_Sodium_Carbonate

ii) On TGA analysis of calcium carbonate minerals (e.g. calcite) containing iron: https://www.researchgate.net/post/How_would_the_addition_of_metallic_iron_to_a_sample_of_CaCO3_effect_the_TGA_and_DSC_curves_of_CaCO3

iii) On TGA analysis of erythritol: https://www.researchgate.net/post/How_to_interpret_a_second_small_step_in_TGA_curve