producing a change of colour

Introduced: January 1980

Full Title

Full titles differ between systems:

IPC:

Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light > Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated > by observing the effect on a chemical indicator > producing a change of colour

CPC:

Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light (G01N3/00 - G01N19/00 take precedence) > Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated (systems in which material is burnt in a flame or plasma G01N21/72, G01N21/73) > by observing the effect on a chemical indicator > producing a change of colour

Of 5 combined children, 3 exist in both systems.

2 codes are CPC-only extensions.

Note: 1 CPC extensions are marked as secondary classification only.

IPC defines codes here since 1980.

Child Classifications

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G01N 2021/786 2nd only CPC only CPC only
G01N 21/783 CPC only CPC only
G01N 21/79 Photometric titration since 1980 IPC+CPC Available in IPC and CPC
G01N 21/80 Indicating pH value since 1980 IPC+CPC Available in IPC and CPC
G01N 21/81 Indicating humidity since 1980 IPC+CPC Available in IPC and CPC