Introduction
The 3rd generation pH probe is a lab-grade mini double-junction Ag/AgCl pH probe capable of measuring pH across a range of 0–14, with a resolution of ±0.001, accuracy of ±0.002, and a response time of 95% within 1 second. The temperature range is -5°C – 99°C, maximum pressure is 110 PSI, maximum depth is 78 meters (254 feet), connector is male SMA, cable length is 1 meter, no internal temperature sensor, time before recalibration is approximately 1 year, and expected lifespan is approximately 2 years. The pH probe works by measuring the activity of hydrogen ions in a liquid; the glass membrane at the probe tip allows hydrogen ions to diffuse, and the difference in hydrogen ion concentration generates a tiny current proportional to the hydrogen ion concentration. Acidic solutions have pH < 7, neutral solutions pH = 7, and alkaline solutions pH > 7. The probe features two junctions: Junction 2 contains 3.5M KCl gel, silver chloride, a high-surface-area Ag/AgCl electrode, and an O-ring; Junction 1 contains a silver wire. Storage life is approximately 5 years, operational life is approximately 2 years, and the soaking bottle pH is approximately 3.8. The probe complies with NSF/ANSI 51 standards and is food-contact safe; the PVC, ABS, glass, polycarbonate, polyethylene, and titanium nitride used all meet NSF-51 standards.
