A few days Sheila Haas requested a reference for glassware detergent checks.
We follow a procedure by: Frings, C.S., "Clinical Chemistry Procedures of Medical Laboratory Associates" Fouth Edition. Medical Laboratory Associates. 1975.
I held off replying because the reference is so old - and - we never use it!(What a hypocrit!). We just keep the stuff on hand to keep what Dr Richmond calls "Der Inspecktors" happy.
The method uses Sulfobromophthalein(Sigma # S-0252) as a 0.5% solution. Since most detergents are alkaline, this solution turns purple in the presence of detergent. We played around with it when we were first required to have it on hand to make sure it worked. Periodically we buy new sulfobromophthalein just to keep and in-date supply on hand.  For non-alkaline detergents I guess you need another method.

Mike Titford
USA Pathology
Mobile AL USA