All of our pH sensors have similar accuracy, response time, and sensitivity, so which one should you buy? It depends on how and where you plan to use your pH sensor. Here is some information to help you choose wisely.

Product Electrode Membrane Electrode Body Junction Type Chemical Compatibility Other Features
Go Direct® pH Sensor (GDX-PH)
or
pH Sensor (PH-BTA)
Glass
Sphere (bulb)
Sealed, gel-filled
Polycarbonate body
Ag/AgCl reference with KCl electrolyte
Single-junction Aqueous Solutions
(not recommended for use with samples containing proteins, organics, heavy metals, sulfides, Tris buffers, or any other biological media)
Best choice for general use (e.g., observe acid-base titrations, investigate water quality)
Go Direct® Tris-Compatible Flat pH (GDX-FPH)
or
Tris-Compatible Flat pH Sensor (FPH-BTA)
Glass
Flat
Sealed, gel-filled
Polycarbonate body
Ag/AgCl reference with KCl electrolyte
Double-junction Aqueous Solutions and Semisolids
(can be used in solutions containing proteins, sulfides, or Tris buffers)
The flat shape makes it robust, easy to clean, allows for small sample sizes, and measurement of semisolid pH (e.g., food or soil slurries)
Go Direct® Glass-Body pH Sensor (GDX-GPH)
or
Glass-Body pH Electrode BNC (GPH-BNC)
Glass
Sphere (bulb)
Sealed, gel-filled
Glass body
Ag/AgCl reference with KCl electrolyte
Single-junction Aqueous and Non-aqueous Solutions Can be used in solutions containing organic solvents and in highly concentrated acids or bases

Also see Answers to the top five questions about pH