[Histonet] NTMT woes

[Johnson, Teri]

We're really stumped on what's going on here. For years we have made
this solution without any trouble or issue. Suddenly in the past several
months, we're having trouble with it going cloudy one day after making
it. I made some yesterday, and by this morning it was cloudy. I checked
the pH and it was 9.3 so I'm not too worried that it's a pH issue. This
cloudiness occurs regardless of whether we use Tris base and pH with
HCl, or if we use Tris-HCl and pH with sodium hydroxide.

Here is the recipe:

NTMT (500 ml)
NaCl 5M............................................10 ml
TrisHCl, 2M, pH 9.5................................25 ml
MgCl2 2M.........................................12.5 ml
Tween-20 (10% in dd water).........................50 ml
q.s. to 500 ml (store at RT)


NaCl 5M (100 ml)
NaCl (FW 58.44)....................29.22 g
q.s. to 100 ml (store at RT)

TrisHCl, 2M (500 ml)
Tris Base (FW 121.1).............121.1 g
Dissolve Tris base in 300 ml of d water. pH to 9.5 with HCl.
q.s. to 500 ml (store at RT)

MgCl2, 2M (100 ml)
MgCl2 (FW 203.3)..................40.6 g
q.s. to 100 ml (store at RT)

If we omit the magnesium chloride, it stays clear. If we add it, by the
next day it is very cloudy and cannot use the solution.

Can anybody give me any information on what might be happening, and what
we need to do? We have already replaced the magnesium chloride, thinking
it had gone bad somehow. It's still happening.

Thanks for any help you can give us.

Teri Johnson, HT(ASCP)QIHC
Managing Director Histology Facility
Stowers Institute for Medical Research
1000 E. 50th St.
Kansas City, MO 64110