The GT Test Kit was invented by Gobthong Thoophom (GT) from the Public Health Ministry. It is a Cholinesterase Inhibition Technique, which detects organophosphororus pesticides and carbamates. The instrumentation is uncomplicated and consists of low-technology items.
- Modified warm water tray (box, sockets, light bulbs, tray)
- Plastic dropper
- Test tubes
- Aquarium pump
- Plastic bottles
- Glass droppers
The instrumentation and chemicals needed are cheap. In 2005, the cost of instruments was about 1500 Bath and chemicals for 10 samples costed 300 Baht.
The pesticides are extracted from the food with an organic solvent. The extract is added
- The enzyme cholinesterase
- Chemical for coloring the extract.
If the samples contain cholinesterase inhibitors like Organophosphororus pesticides and carbamates, some of the enzyme is inhibited. The remaining enzyme will metabolize some of the acetylcholine. The remaining acetylcholine will together with chemicals develop a red color. If the extract develops a dark red color, the sample is regarded as unsafe and cannot be sold as certified.