Hi I want to ask that i have a sample CaCO3 and when i analyze it using SEM i got result but using EDX Oxygen is about 50% which is very HIGH AS COMPARED TO LITERATURE AND CALCIUM % is low what shuld i do?
What should you do - not use EDS for the light elements, because you would easily get humongous errors.
The problem is that you are a) a beginner, and b) EDX has some limitations you should know before you start to use a technique seriously. There are people here in Researchgate which are absolutely convinced that EDX is a technique which only can be used qualitatively. And they are right if you include light elements, or superimposing elements. But there are many materials where it works excellent, and for several problems tricks exist which you need to know and partly understand. I always use here the example with a racing car. If you get it, and you just made your driving licence...do you really expect that you will win the next race? You possible will never win a race, but you can try to understand your car , you can try to improve your feelings for the car. And if you do not win it is often not the cars reason. You need to read some books and learn some fundamentals about this technique. By asking a question: how I can get better results? nobody can really help you. Only some recommendations which you need to understand and assimilate. Science is a huge amount of believe (other people possibly call it knowledge), long-life experience, intuition, willingness to make sacrifices, humbleness, and self-criticism. Especially the last I am often missing here at Researchgate.
Do you really need to know the concentration of calcite, a phase where everything is known, especially the chemical composition? Why do you need it? Can you use indirect ways? In mathematics some things you cannot prove, but you can turn the question around and can prove that the opposite is not correct. What is your actual problem?
1. Quantitative EDX is working from F and forward, in real world from Na. Want to analyze С and O go to WDX (wave dispersive), but you will still have higher С than should, simply because carbon-based compounds are everywhere.
2. O content is used in EDX to reach 100% of total composition. For example, you got a spectrum, selected 3 elements Ca, C, O. Fitting will give you raw data in at % Ca - 19%, C - 18%, O - 50%. As you can see, it's not 100% exactly (because of different reasons), so program fills the gap with light elements that are present everywhere.
3. X-ray WDX, ICP-MS or any other MS-based techniques with proper calibration can help you.
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