Ion-selective electrode and production method therefor
View Patent ↗An ion-selective electrode includes: an ion-sensitive layer containing an ion-sensitive substance; and a solid, in which at least a part of a surface of the solid is coated with the ion-sensitive layer, the ion-sensitive substance has a crown ether structure formed of at least two or more repeating units represented by Formula (a): —CR 1 R 2 —CR 3 X—O— (a) where X is an organic group having an alkoxysilyl group at a terminal, R 1 , R 2 , and R 3 are each a hydrogen atom or a hydrocarbon group, and R 1 or R 2 may be bonded to X, and at least one of the alkoxysilyl groups of the crown ether structure reacts to be bonded to at least a part of the surface of the solid.
1. An ion-selective electrode comprising:
an ion-sensitive layer containing an ion-sensitive substance; and
a solid,
wherein at least a part of a surface of the solid is coated with the ion-sensitive layer,
the ion-sensitive substance has a crown ether structure formed of at least two or more repeating units represented by Formula (a):
—CR 1 R 2 —CR 3 X—O— (a)
where X is an organic group having an alkoxysilyl group at a terminal, R 1 , R 2 , and R 3 are each a hydrogen atom or a hydrocarbon group, and R 1 or R 2 may be bonded to X,
at least one of the alkoxysilyl groups of the crown ether structure reacts to be bonded to at least a part of the surface of the solid,
the ion-sensitive layer contains a portion derived from a second compound represented by Formula (c):
R 4 —Z (c)
where R 4 is a monovalent hydrocarbon group, and Z is a monovalent organic group having an alkoxysilyl group at a terminal, and
a ratio of a molar number of a portion derived from the second compound to a sum of a molar number of a portion derived from a portion represented by Formula (a) and a molar number of a portion derived from the second compound is 0.9 or less.
2. The ion-selective electrode of claim 1 , wherein
the crown ether structure is a polymer containing a portion derived from a first compound having an epoxy group and an alkoxysilyl group at a terminal, and
the polymer is obtained by cyclically polymerizing the epoxy group by ring-opening with an alkali metal salt or a salt of a group 2 element.
3. The ion-selective electrode of claim 2 , wherein
a cation of the alkali metal salt or the salt of the group 2 element is any of lithium ion, sodium ion, and potassium ion.
4. The ion-selective electrode of claim 1 , wherein
in Formula (a), R 1 , R 2 , and R 3 are each a hydrogen atom, and X is represented by Formula (b):
—CH 2 O—Y (b)
where Y is a monovalent organic group having an alkoxysilyl group at a terminal.
5. The ion-selective electrode of claim 1 , wherein
the number of repetitions of Formula (a) is 10 or less.
6. The ion-selective electrode of claim 1 , wherein
at least one of the alkoxysilyl groups of the crown ether structure reacts to form a siloxane bond.
7. The ion-selective electrode of claim 1 , wherein
a siloxane bond is formed from a portion derived from the alkoxysilyl group in the crown ether structure and a portion derived from the alkoxysilyl group of the second compound.
8. The ion-selective electrode of claim 1 , wherein
a ratio of a sum of a molar number of a portion derived from a portion represented by Formula (a) in which the number of alkoxy groups in X of Formula (a) is 3 and a molar number of a portion derived from the second compound in which the number of alkoxy groups in Z of Formula (c) is 3 to a sum of a molar number of a portion derived from a portion represented by Formula (a) and a molar number of a portion derived from the second compound is 0.9 or less.
9. The ion-selective electrode of claim 1 , wherein
the solid contains a conductive material.
10. The ion-selective electrode of claim 1 , wherein
the solid is a glass container,
the surface of the solid is an outer surface of the glass container, and
the ion-selective electrode further comprises:
a conductive member so that the conductive member comes into contact with an electrolytic solution when the glass container is filled with the electrolytic solution.
11. An ion-selective electrode comprising:
an ion-sensitive layer containing an ion-sensitive substance; and
a solid,
wherein at least a part of a surface of the solid is coated with the ion-sensitive layer,
the ion-sensitive substance has a crown ether structure formed of at least two or more repeating units represented by Formula (a):
—CR 1 R 2 —CR 3 X—O— (a)
where X is an organic group having an alkoxysilyl group at a terminal, R 1 , R 2 , and R 3 are each a hydrogen atom or a hydrocarbon group, and R 1 or R 2 may be bonded to X,
at least one of the alkoxysilyl groups of the crown ether structure reacts to be bonded to at least a part of the surface of the solid,
the ion-sensitive layer contains a portion derived from a second compound represented by Formula (c):
R 4 —Z (c)
where R 4 is a monovalent hydrocarbon group, and Z is a monovalent organic group having an alkoxysilyl group at a terminal, and
a ratio of a sum of a molar number of a portion derived from a portion represented by Formula (a) in which the number of alkoxy groups in X of Formula (a) is 3 and a molar number of a portion derived from the second compound in which the number of alkoxy groups in Z of Formula (c) is 3 to a sum of a molar number of a portion derived from a portion represented by Formula (a) and a molar number of a portion derived from the second compound is 0.9 or less.