Chromoionophores, optical sensors containing them and a method for determining the presence of alkali metal cations or of a base

PCT No. PCT/IE93/00046 Sec. 371 Date Mar. 28, 1995 Sec. 102(e) Date Mar. 28, 1995 PCT Filed Aug. 6, 1993 PCT Pub. No. WO94/04483 PCT Pub. Date Mar. 3, 1994New chromoionophores of the formula IV IV wherein a=0-3, b=0 or 1, c =0 or 1, x=0 or 1, y=0 or 1, z=0 or 1, R', which may be the same or different in each aryl group, is H, halogen, hydrocarbyl, aryl, hydrocarbylaryl or a substituted derivative thereof; R, which may be the same or different, is hydrocarbyl, aryl, hydrocarbylaryl, or a substituted derivative thereof are useful in optical sensors or colourmetric reagents for clinical use particularly for lithium, When complexed with lithium, the chromoionophores of the invention and other calixarene derivatives can be used for detecting amines, particularly trimethylamine, as an indicator of fish spoilage.