phenolpthalein problem

[ece421]

Today I was making more phenolpthalein in house, I was using 0.08% phenolphthalein powder in methanol (137.5 g methanol and 0.11 g phenolphthalein powder in a sealed flask with a stir bar).  Everything I used was clean.  For some reason, I made it twice but it turned pink immediately upon addition of the methanol.

Something doesn't seem right, I've made it a few times before using 0.1% and 0.08% phenolphtalein as above and it never turned pink before. 

Is my phenolphtalein powder done or should I try using fresh methanol tommorrow?  Can you also make it with isopropyl alcohol?  I'd use ethanol but was asked not to use our ethanol until we "absolutely" need it (it's reagent grade so any moisture that gets into it is going to ruin it).

[marquis]

I've had phenolphthalein go bad.  Usually, it takes 5 years or more for this to happen.
It doesn't seem likely that it is the problem.

The soap for the glassware sounds like a reasonable guess.  It wouldn't take much residual basic soap to turn the phenolphthalein red.  Has something changed (detergent or wash procedure) with your glassware?

Methanol is a possibility.  I'd look at the glassware, first.

[ece421]

We've had the phenolphthalein powder for more than 4 years now, so it wouldn't surprise me (even though it's been stored in clean, dry, cool area).

I've used two clean flasks and had the same thing happen.  I use dawn in the lab, but I always rinse really really well.  Should I try a third flask?

You said the methanol is a possibility, should I try fresh methanol?

[marquis]

Check the pH of the water before you rinse with it.  Use pH paper, if nothing else. Then try checking the pH of your last water rinse in the glassware. 

Most DI water has a pH of 5.5 to 7.  If either test is above this, the water is probably the issue. 

If you can order the methanol, do it.  At the very least, you want to make sure the new bottle of methanol is from a different vendor lot.  A better idea would be to order the next higher grade of methanol.

You're troubleshooting with the methanol.  Try ordering the minimum amount you need to get by.