Nomenclature Problem - e.g., 3 x phophate-buffered saline (Apr/02/2009 )

hi everyone.................

I a little nomenclature problem (should be simple to the rest of you).................

what does it mean when protocols speak of e.g., 1 x phosphate buffered saline (PBS), 3 x PBS, etc...............

a text example: "Bacterial cultures are harvested by centrifugation and resuspended in 1 x PBS.....................

thanks

Standard solutions with several components at different concentrations, so it is easier to write 1x or 3x than to write out the list of components and their concentrations. 3x is obviously 3 times the standard concentrations of a 1 x solution.

Yes -- 3X PBS is three times as concentrated as 1X PBS. To make 1X PBS from 3X PBS, one would do a 1:3 dilution, e.g. combine 20 ml of 3X PBS + 40 ml of dH2O to make 60 ml of 1X PBS. To make 3X PBS, one would dissolve the components for 1X PBS in one-third the volume.

thanks for your replies !!!!!!!!!!!!!!!!!!!!!