PH indicator device and formulation
Disclosed herein are devices and methods for determining the pH of fluid. Example devices include a device comprising a surface configured to contact the fluid and a pH indicator covalently bound thereto, wherein the pH indicator has a first color prior to contact with the fluid and changes color as a function of the pH of the fluid.
1. An article of manufacture, comprising:
a fluid-contacting surface, wherein the article of manufacture further comprises a gel positioned on the fluid-contacting surface, the gel configured to contact the fluid, the gel comprising a pH indicator comprising 2-[(4-(2-hydroxyethylsulfonyl)-phenyl)diazenyl]-4-methylphenol and 4-[4-(2-hydroxyethylsulphonyl)-phenylazo]-2,6-dimethoxy phenol in about a 2:1 ratio.
2. The article of claim 1 , wherein the gel is an adhesive.
3. The article of claim 1 , further comprising a conduit configured to direct fluid to the pH indicator.
4. The article of claim 1 , wherein the fluid contacting surface comprises a film.
5. The article of claim 1 , wherein the fluid contacting surface comprises an absorbent pad.
6. The article of claim 1 , wherein the fluid contacting surface comprises a mesh.
7. The article of claim 1 , wherein the article is configured to indicate food spoilage.
8. The article of claim 7 , wherein the article is configured to be positioned on a food package.
9. The article of claim 1 , wherein the article is configured to be placed in a wound.
10. The article of claim 1 , wherein the fluid-contacting surface is a coating, the coating configured to be placed on a packaging material.
11. The article of claim 1 , wherein the article is configured to monitor drug release.
12. The article according to claim 1 , wherein the colour change in the pH indicator is detectable at a 0.1 unit interval change in pH.
13. The article according to claim 12 , wherein the colour change in the pH indicator is detectable between about pH 5 and about pH 10.
14. The article according to claim 13 , wherein the colour change in the pH indicator is detectable between about pH 5.5 and about pH 9.5.
15. The article according to claim 13 , wherein the colour change in the pH indicator is detectable between about pH 6.5 and 9.5.
16. The article according to claim 1 , wherein the article comprises a cellulosic material.
17. The article according to claim 1 , wherein the article comprises a peripheral edge, the pH indicator positioned on the peripheral edge.