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International
Standard
ISO 7383-2
First edition
Fine bubble technology —
2024-07
Evaluation method for determining
gas content in fine bubble
dispersions in water —
Part 2:
Hydrogen content
Reference number
© ISO 2024
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ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle and application . . 2
4.1 General .2
4.2 Titration (oxidimetry) method .2
4.3 Gas chromatography .2
5 Apparatus and materials . 2
5.1 Titration (oxidimetry) method .2
5.1.1 Reagent .2
5.1.2 Dropper or titrator .3
5.1.3 Clear vial .3
5.2 Gas chromatography .3
5.2.1 Vial and clamping machine .3
5.2.2 UFBs elimination .3
5.2.3 Carrier gases and column .3
5.2.4 Gas chromatograph .3
5.2.5 Measurement device for UFB size and concentration .4
6 Procedure . 4
6.1 Titration (oxidimetry) method .4
6.2 Gas chromatography .4
6.2.1 General .4
6.2.2 Sample sealing .5
6.2.3 UFBs elimination .6
6.2.4 Analysis of gas substitutes .6
7 Results and calculation . 8
7.1 Titration (oxidimetry) method .8
7.2 Gas chromatography .8
7.2.1 General .8
7.2.2 Calibration curve for hydrogen concentration measurement .8
7.2.3 Volume of the water sample in the vial .9
7.2.4 Volume of the headspace above the UFB dispersion in the vial .9
7.2.5 Pressure of the gas in the vial headspace .10
7.2.6 Hydrogen content in the vial head space .10
7.2.7 Hydrogen content in the vial water sample .10
7.2.8 Hydrogen content in association with each number concentration of UFBs and
dissolved hydrogen .11
8 Error of measurement .12
8.1 Titration (oxidimetry) method . 12
8.2 Gas chromatography . 12
8.3 Relative standard deviation of the gas chromatograph . 13
9 Test report .13
9.1 Testing results. 13
9.2 Testing conditions . 13
Annex A (informative) Example of test result at testing laboratory by titration (oxidimetry)
method . 14
Annex B (informative) Example of test result at testing laboratory by gas chromatography
using the capillary column . . 17
iii
Annex C (informative) Example of test result at testing laboratory by gas chromatography
using the packed column.20
Annex D (informative) Comparison of different vials when testing the hydrogen content by gas
chromatography .23
Bibliography .25
iv
Foreword
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This document was prepared by Technical Committee ISO/TC 281, Fine bubble technology.
A list of all parts in the ISO 7383 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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v
Introduction
Hydrogen has recently attracted considerable research attention across several fields, such as agriculture,
food, environment, and medicine sciences, owing to its antioxidant capacity and zero-residual and ecofriendly
properties. Hydrogen concentration is a crucial parameter to ensure its successful hydrogen application.
At present, there are potential limitations regarding the application of hydrogen in living organisms,
such as accessibility, availability, and biological intake. For example, hydrogen exhibits low solubility,
with
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