I did ICP for my sample, and i got Ni=135.42, Zn=232.78, Fe=721.73 mg/L. i want to know the exact concentration obtained. i have synthesized it as Ni0.4Zn0.6Fe2O4. please elaborate the method, as i already tried two diff method and i got similar but not exact results, thanks
Hello,
The result may differ depending on element that you choose as a reference during calculation. Dividing your concentration values by atomic masses you obtain the following concentration of elements: Ni: 0,0023074 mol/L, Zn: 0,00355987 mol/L, Fe: 0,01292264 mol/L. If you choose Fe as a reference you have to divide concentrations of Ni and Zn by Fe. In a such a way the stoichiometry is Ni(0.1785)Zn(0.2754)Fe(1). Assuming that your compound should to have two equivalents of iron, the stoichiometry is Ni(0.3571)Zn(0.5509)Fe(2). It means that you have too much iron in your compound or not enough Ni and Zn. If the reference element is for example Ni the conclusion is similar, however the calculated stoichiometry will differ. Anyway there is too much iron to obtain theoretical stoichiometry value. Hope it helps.
Best
Artur
thanks for calculating, prof @artur krezel. you might read it wrong, Fe concentration is what i want, that is double of the combine Ni and Zn. Thanks for the method
Dr. Krezel, thanks.
But, How can we calculate the chemical structure without a reference metal?
For example,
theoretical Formula Li1.05(Ni0.323Mn0.323Co0.323Mo0.02)O2
calculated Formula Li0.984 (Ni0.318Mn0.340Co0.337Mo0.019)O2
I got these formulas from article in the link below.
Article Mo doping of layered Li (Ni x Mn y Co 1- x - y - z M z )O 2 ...
Dear colleague,
My research group has experience in the determination of the content of the major components Sr, Li, Ti, Fe and Nb in single crystals, based on strontium–lithium–titanium oxides by inductively coupled plasma atomic emission spectrometry (ICP-AES) [1].Owing to the lack of certified reference materials the accuracy of ICP-AES was evaluated: using analysis of a single crystal with well-known composition— SrLi2Ti6O14. By using the quantitative data obtained by ICP-AES the composition of SrLi2Ti6O14was experimentally demonstrated. Hence, the selected dissolution, calibration and background correction procedures can provide accuracy of analytical data.
I pay attention that analytical task require the determination of matrix elements (Sr, Li, Ti, Fe and Nb). In this case, after dissolution of the sample must be selected an appropriate dilution factor, which permit to measure the corresponding analytical signals of matrix constituents with desire level of precision (in this case the dilution factor = 20).
In addition, the same single crystal was analyzed by electron-probe microanalysis (EPMA) using CAMECA Camebax SX 50 equipment, i.e direct method for determination of Sr, Li, Ti, Fe and Nb. Crystal growers expected to obtain strontium–lithium–titanium–iron–niobium oxide phases with the composition SrLi2Ti4NbFeO14.
Using the concentrations obtained by ICP-AES the following formula was calculated— SrLi2Ti5.17Nb0.6Fe0.27O14.25. Using the concentrations obtained by EPMA the following formula was calculated SrLi2Ti5.16Nb0.58Fe0.26O14.16.
No significant statistical differences were found.
By this methodology we solved successfully this analytical take.
With kind regards, N.Daskalova
References
[1]. A. Detcheva, N. Daskalova*, S. Velichkov, I. Havezov, Analysis of single crystals based on strontium–lithium–titanium oxides by inductively
coupled plasma atomic emission spectrometry, Spectrochimica Acta Part B 58 (2003) 1481–1488
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