ISO 7383-1:2024

Overview

ISO 7383-1:2024 - Fine bubble technology - Evaluation method for determining gas content in fine bubble dispersions in water - Part 1: Oxygen content defines standardized methods to measure oxygen content in water containing fine bubbles. The document specifies three accepted measurement approaches: optical sensor, electrochemical probe, and the iodometric (chemical) method. It addresses practical measurement ranges, interferences, sampling and calibration requirements, and interpretation of results when microbubbles (MB) or ultrafine bubbles (UFB) are present.

Key topics and requirements

• Three measurement methods
  • Optical sensor: in situ, real-time, widely available; check instrument range for supersaturation.
  • Electrochemical probe: in situ, real-time; detection limits typically 0.1–0.2 mg/L depending on the instrument.
  • Iodometric method: laboratory chemical analysis; measurement range 0.2–20 mg/L; useful where sensor instruments are unavailable.
• Detection limits and ranges
  • Electrochemical and optical sensors: detection limits commonly 0.1 mg/L or 0.2 mg/L; upper limit depends on instrument specification (many handle supersaturated samples).
  • Iodometric: 0.2–20 mg/L.
• Sampling and handling
  • Minimize oxygen uptake and stripping during sampling, transport and storage.
  • Follow instrument calibration and sampling precautions; be aware of bubble attachment to sensors.
• Interferences
  • Iodometric: oxidizable organic matter (tannins, humic substances), sulfides and other reducing agents can interfere.
  • Electrochemical: gases/vapors (chlorine, H2S, ammonia), solvents, oils, biofilms and membrane deterioration can affect readings.
• Salinity correction
  • For saline waters, input salinity into instruments or apply compensating procedures referenced from ISO 17289 / ISO 5814.
• Result interpretation
  • MBs that remain in sample can change dissolved oxygen as they dissolve; UFBs typically contribute negligibly to dissolved oxygen but affect how results are interpreted. Presence of UFBs should be verified (see ISO/TR 23015).

Applications

• Aquaculture and fish farming (oxygen control in tanks)
• Food-processing and storage where oxygen affects oxidation
• Environmental and water-quality monitoring where fine bubble aeration is used
• R&D and process control for fine bubble generation systems
• Calibration and testing services, instrument manufacturers and quality control labs

Who should use this standard?

• Environmental and water-quality laboratories
• Aquaculture operators and food-processing engineers
• Instrument suppliers and manufacturers of oxygen sensors
• Researchers and consultants working with fine bubble technology and ultrafine bubble (UFB) dispersions

Related standards

• ISO 17289:2014 - Optical sensor method for dissolved oxygen
• ISO 5814:2012 - Electrochemical probe method
• ISO 5813:1983 - Iodometric method (dissolved oxygen)
• ISO 20480-1 - Fine bubble terminology
• ISO/TR 23015 - Measurement techniques for fine bubbles

Keywords: ISO 7383-1:2024, fine bubble technology, oxygen content, optical sensor, electrochemical probe, iodometric method, dissolved oxygen, ultrafine bubbles, in situ measurement.