Novel Ferrocene Labels For Electrochemical Assay and Their Use in Analytical Methods

Compounds of general formula I are used as labels in an electrochemical assay: (I) in which: Fc and Fc' are substituted or unsubstituted ferrocenyl moieties, X is a C1 to C6 alkylene chain which is optionally interrupted by - O - or - NH -; Y is a C1 to C6 alkylene chain which is optionally interrupted by - O - or - NH -; Z is a C1 to C12 alkylene chain which may optionally be substituted and/or may optionally be interrupted by - O -, - S -, cycloalkyl, - CO -, - CON R1 -, - NR1CO - or - NR1 - in which R1 represents hydrogen or C1 to C4 alkyl; and R is a linker group. Compounds I are used to make labelled substrates, as well as functionalised compounds for making the labelled substrates.