Please all . I need to know how to calculate the spike samples for food analyses . I spiked the sample before microwave digestion ( in solid phase ) i spiked 5 ppb and i get instrument result of 35 ppb . How can we get recovery for that ?
Hello,
A few things might influence your result like what kind of food you are taking about (processed or raw) and if those are contaminated with your concerned heavy metals earlier or not. For example, food items from processed rice grains can have arsenic contamination over 35 ppb as well as raw rice grains will definitely have higher content of arsenic before you spike. But that depends on which type of food samples you are spiking. If those samples are having heavy metals earlier than your spiking then its better to digest both non-spiked and spiked samples of the same source and subtract the result.
Alternatively, you can also try to use teflon beakers and go for the acid digestion process to cross check your result and if the microwave digestion process is right or not.
You might have done some error...
after digestion you have to dilute your samples
and with spiked samples
the output should be near equal or less than Known amount...
Ok but how to spike food sample . I have a cereal food sample and i will digest it in microwave digester and we have multielemnt standard. So how we spike it ?
The intention of spiking is to assess the ability of any plant species (cereals in your case) to uptake the applied content of heavy metals. But if you have only grains of cereals that will have no effect of spiking. On the other hand, if you have seeds of cereals, and spike with heavy metals, that might effect in seed germination rate know as seed priming (although that is for germination enhancement and not for suppression). So, with seeds of cereals, spiking can be done (grow till the seedling stage) before digestion but with grains of matured cereals, spiking is not an option to go with. It is better to analyze your food samples without spiking as spiking needs a live system to be effective.
Dear
Spiking sample is performed at the beginning of the digestion method
Just weight a sample in duplicate
One of them unspike contain only sample
The other you spike with a known concentration of metal
After measurement
recovery %= (spike - unspike / added conc. ) *100
Dear Dr. Karim Mosa
Please go through the following attached file. Its may be helpful to you.
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