ORP (Oxidation-Reduction Potential) measures the overall electrical potential of a solution to act as an oxidizer, expressed in millivolts (mV). It reflects the combined effect of all oxidants and reductants present in the sample — not just ozone. ORP is governed by Nernst-logarithmic behavior, meaning it responds non-linearly to concentration changes and is strongly influenced by pH, temperature, electrode condition, and matrix composition. Source: Suslow (2004), UC ANR Publication 8149
We use a Hanna Instruments calibrated digital ORP electrode with an Ag/AgCl (silver/silver chloride) reference. Hanna Instruments is an ISO 17025 accredited manufacturer with NIST-traceable calibration standards. The electrode is inserted directly into the glycerin during and after the ozonation cycle. Readings are verified routinely against our validated indigo dissolved ozone assay, with defined error windows and documented remedial actions when drifts occur.
ORP provides valuable process consistency monitoring — it confirms that the ozonation environment maintained sufficient oxidizing capacity throughout the production cycle. Values above 450 mV indicate a strongly oxidizing environment consistent with effective ozonation. However, ORP is a mixed redox potential, not a direct measure of ozone concentration. It should not be converted to an ozone ppm value without a matrix-specific correlation study. We report it as a supporting parameter alongside our primary dissolved ozone assay. Source: Suslow (2004), UC ANR Publication 8149
SimplyO3 Glyzine must achieve an ORP of not less than (NLT) 450 mV. Our batches typically read 550–650 mV, confirming a strongly oxidizing environment consistent with thorough ozonation.
ORP and dissolved ozone (mg/L) are independent measurements made with different instruments. A high ORP does not directly equate to a specific ozone concentration. ORP is best understood as confirming that oxidation occurred and was maintained, while the indigo assay tells you how much ozone remains. Together, they provide complementary evidence of product quality.
Stated accuracy: ±1 mV instrument resolution. Here is what the science says about ORP measurement and its limitations:
The Instrument: We use a Hanna Instruments calibrated ORP electrode with Ag/AgCl reference, manufactured under ISO 17025 accreditation with NIST-traceable calibration. Resolution is ±1 mV. However, instrument resolution is not the whole picture for ORP.
Why ±1 mV Does Not Mean ±1 mV Reproducibility: ORP is a mixed redox potential governed by the Nernst equation: E = E° + (RT/nF) × ln(a_ox/a_red). Suslow (2004) explains that ORP “integrates all oxidant and reductant couples present” and responds logarithmically, not linearly, to concentration changes. In practice, day-to-day ORP readings on the same sample can vary ±10–15 mV due to electrode conditioning, temperature drift, matrix aging, and dissolved gas equilibria.
Indirect Method Bias: Multiple studies comparing ozone analytical methods have shown that iodometric (indirect redox) methods systematically overestimate ozone by 15–30% compared to direct UV measurement. Gordon et al. documented this in water treatment, and the effect compounds in complex matrices like glycerin. This is precisely why we do not convert ORP to ozone concentration: the relationship is not fixed and indirect redox methods introduce systematic bias.
What Our ORP Tells You: An ORP above 450 mV confirms a strongly oxidizing environment. Values of 550–650 mV (our typical range) are consistent with thorough ozone saturation. We report ORP as a supporting indicator alongside our primary dissolved ozone assay — never as a standalone potency claim.