Compositions for conjugating a sulfonephthalein dye to a substrate
The present invention provides derivatized indicator compounds, such as pH indicator compounds, which can be covalently immobilized to a variety of solid substrates to produce an indicator pad. Such pads can be used to monitor water quality in variety of settings. In particular, the pads of the invention are useful in devices which monitor the quality of recreational water, such as water in swimming pools, hot tubs, and amusement park attractions, including water slides, and water-based rides. The present invention overcomes the limitations of commercially available pad chemistries.
1. A composition comprising (a) a methylol derivative of a sulfonephthalein dye compound and (b) an oligomer of the sulfonephthalein dye compound.
2. The composition of claim 1 , wherein the sulfonephthalein dye is selected from the group consisting of phenol red, cresol red, m-cresol purple, xylenol blue, thymol blue, chlorophenol red, bromophenol blue, bromocresol purple, bromocresol green, bromothymol blue, xylenol orange, and methylthymol blue.
3. The composition of of claim 1 wherein the methylol derivative of the sulfonephthalein dye is selected from compounds represented by Formula (I)
wherein R 1 , R 2 and R 3 for each compound are set forth in Table 2,
TABLE 2
Compound
R 1
R 2
R 3
1
HOCH 2 —
H
H
2
Me
HOCH 2 —
H
3
HOCH 2 —
H
Me
4
H
HOCH 2 —
Me
5
Me
HOCH 2 —
Me
6
i-Pr
HOCH 2 —
Me
7
Cl
HOCH 2 —
H
8
CH 2 N(CH 2 COOH) 2
HOCH 2 —
Me.