What analytical method(s) to use for finding the contaminations in a fatty base material In a large batch of a fatty combustible mixture there appear to be two contaminations, since after combustion there are 2 residues clogging up the injectors and exhaust system:
- a calcium salt
- a phosphate

We can easily analyse these residues, but to find a method to remove these contaminations before they are combusted we need to find out what form they have in the base material. 
From that information we could try to 'wash them out' and quantify the contamination in both the 'washing sollution' and in the combustion gasses to optimize this process.
But for starters we need to know where the contamination is comming from in the first place, so hence my question: what analytical method(s) could be used to figure out these (probably small) contaminations in this fat ?
I have found that with the ICP-MS method we can at least get a quantitative approach of the elements in these samples.
Unfortunately it is not so easy to figure out the form these contaminations are in, especially the phosphate.