Qiagen LyseBlue

In article <[Only registered users see links. ].net >, "Sharon Waldrop" <[Only registered users see links. ]> wrote:

Well, it is quite obviously a pH indicator that transitions from
blue at basic pH to colorless at lower pH. The color looks
exactly what I'd expect from thymophthalein. So I'd say it is
thymophthalein.

Which is incredibly easy to check - titrate some of the
LyseBlue with 0.1 M NaOH with acid monitoring pH. If the
color changes around pH 9.3 - bingo, you know for sure
it's thymophthalein. If the color changes at a lot lower pH,
that was a wrong guess.

(If you do decide to to this simple experiment, please
report back here. I think others would be interested to have
your question answered unambiguously).

DK

In article <NJPfk.11$[Only registered users see links. ]>, [Only registered users see links. ] (DK) wrote:

Definitely thymophthalein. I did a crude titration and the
color completely disappeared at pH 9.2.

DK