Hi there,
For one of my projects, i need to determine the fat concentration (mg/l) in a water stream.
I've collected samples and send them to a lab where they can measure this.
I've asked them what the standard deviation of their analyze method is, but they responded that they don't know. Therefore, I would like to create an validation test for their analyze method.
My thoughts are to make a 1L solution of XX mg of fat (let's say 100 mg fat), divide this into ten 100 ml samples. These ten samples should then be measured to see if they all produce the same result (100 mg/l). The problem I foresee is that you divide the 1L solution into ten 100 ml samples, the concentration of fat won't be the same in each sample, because fat does not dissolve into water and therefore won't distribute evenly over each 100 ml sample.
What would be the best way to tackle this problem?
FYI: the analyze method consists of adding a surplus of acid to the water samples, after which the fat precipitates. They then seperate, dry and weigh the precipitation.