Re: dWater as sheath plus ARIA question

Hi Alice,

laser light "bounce", otherwise known as diffraction, does occur at the 
sheath-sample interface when running liquids with different refractive 
indices such as ddH2O, bleach, etc.. This is readily detected in 
"forward" scatter (FSC) with log-amplification as one may use to detect 
small particles such as bacteria.  

It is not uncommon to attribute the noise from this diffraction to 
debris in the sample.  

good luck, TomD


Alice L. Givan wrote:

>To Howard et al,
>As Howard said, you cannot use distilled water in the sheath stream if you are sorting
as
>distilled water will not take the charge needed for sorting.
>
>But, even for non-sorting applications,  I have always thought (although have not
tested)
>that using distilled water as sheath fluid will raise	background signals --- because
>light will bounce off the interface between the core stream and the sheath fluid  (they
>no longer have the same refractive index).
>
>Is this incorrect?
>
>Alice
>
>Alice L. Givan, Director
>Englert Cell Analysis Laboratory
>of the Norris Cotton Cancer Center
>Dartmouth Medical School
>Lebanon, NH 03756 USA
>tel 603-650-7661
>fax 603-650-6130
>givan@dartmouth.edu
>www.dartmouth.edu/~celllab
>
>
>  
>