3 replies to this topic

[GaoYuQing]

Anyone come across a table for a turbidometer that tells you what %light transmittance equates to population density of microbes in suspension?

[pito]

This is impossible because it depends on the liquid, "bottles" you use etc..
(you need a reference sample, blanco)

[GaoYuQing]

That's why you use a blank vial with your fluid to start with, to "zero" it out at 100% transmittance, then you add your organisms to the requried % transmittance to get the required population.  It was my (perhaps incorrect) understanding that with this zero-ing out process, the rest should be standard since the only remaining variable would be the suspended particles.

Edited by GaoYuQing, 13 February 2012 - 08:18 AM.

[pito]

GaoYuQing, on 13 February 2012 - 08:17 AM, said:

That's why you use a blank vial with your fluid to start with, to "zero" it out at 100% transmittance, then you add your organisms to the requried % transmittance to get the required population.  It was my (perhaps incorrect) understanding that with this zero-ing out process, the rest should be standard since the only remaining variable would be the suspended particles.

The susended particles are indeed very important, but the liquid itself is also very important.. and everyone uses another type of media (or even if it is the same type, people prepare it differently or there are always others parameters that make it a bit different).

So you always need to use your own blanco.
+ the machines themself, they are not the same either.. so there are always parameters that differ , so you always need to take your own blanco.