3 replies to this topic

[Antonio Sillo Rosato]

Hi to all,

i need to quantify the intracellular metal absorbed in e.coli after treating.

I have used a total volume of 3ml, then i have pelletted them and washed with a buffer containing edta in order to chelate the unbound metal. eventually i have resuspend the pellet in 3 ml of water and digested the cells with other 3ml of digestion mixture before icp-ms analysis.

the results have been multiplied by two in order to take in account for the dilution factor, i'm wandering is should i have to correct also the values for the pellet, for example should i have to tonsider that the pellets have been resuspended in 3ml? so should i have to consider a dilution factor of three for these samples?

thank you

[bob1]

What are the units that you are getting out for your metal concentrations? If they are coming out as (for example) XX ug/ml then, no you don't need to compensate for dilution, other than that to get total amount, you have to multiply by the number of ml you have used to prepare the sample for MS

[El Crazy Xabi]

Measuring concentrations inside the cells is not that easy. Also, cells may die after the heavy metal (HM) treatment and lose the cellular integrity becoming permeable, cellular content being discharge into solution...

Often this studies give concentrations based on the cellular dry weight/biomass dry weight instead of a more "natural" measurements e.g. ng HM//nL cytoplasm, as you should have cell counts and calculate, at least, the average cell volume as approximation to the internal cell volume, which is not as easy.

[Andrea Fortina]

I saw some kits could measure the metal, but not the total metal concentration, just for specific one. For example, 

http://www.creativeb...search_Iron.htm

http://www.creativeb...-Kit-462630.htm