Abstract: The invention provides an electrochemical assay for a phenol analyte in a body fluid sample wherein said sample, or fluid therefrom, is contacted with the working electrode of an electrode assembly comprising a working electrode, a counter-electrode, a voltage supply to said working and counter-electrodes and a current meter for determining the current between said working and counter-electrodes, and wherein a first compound capable of reversible oxidation and reduction is disposed at said working electrode, said first compound being capable in either an oxidized or a reduced form of binding to said phenol analyte, characterized in that said first compound in its oxidized or reduced form comprises a group of structure I R1-NH—C*—(C*—C*)n—C*-QR? (I) (where n is 0 or 1; Q is 0, S, NH or NR?; C*—(C*—C*)n—C* is a two or four carbon string in a conjugated delocalised electron system optionally substituted by a group comprising R; R is an electron-donating or withdrawing substituent; and R? is H or a group R, at le

Abstract: The invention provides a method of assaying for tetrahydrocannabinol in a body fluid. The method includes contacting a sample of body fluid with an imine capable of reacting with tetrahydrocannabinol to yield a quinone imine, and detecting the formation of a quinone imine, where the sample is contacted with the reagent compound at a pH of at least 10.5.

Abstract: The invention provides an assay method for the detection of a primary amine analyze in an aqueous body fluid, which method comprises contacting a sample of said body fluid at a pH below 9.5 with a thiol and an unsaturated cis-dialdehyde and testing for the presence of a pyrrole reaction product.

Abstract: The invention provides a method of assaying for tetrahydrocannabinol in a body fluid, said method comprising contacting a sample of body fluid with an imine capable of reacting with tetrahydrocannabinol to yield a quinone imine, and detecting the formation of a quinone imine, characterised in that said sample is contacted with said reagent compound at a pH of at least 10.5.

Abstract: The invention provides an assay method for the detection of a primary amine analyte in an aqueous body fluid, which method comprises contacting a sample of said body fluid at a pH below 9.5 with a thiol and an unsaturated cis-dialdehyde and testing for the presence of a pyrrole reaction product.

Abstract: The invention provides an electrochemical assay for a phenol analyte in a body fluid sample wherein said sample, or fluid therefrom, is contacted with the working electrode of an electrode assembly comprising a working electrode, a counter-electrode, a voltage supply to said working and counter-electrodes and a current meter for determining the current between said working and counter-electrodes, and wherein a first compound capable of reversible oxidation and reduction is disposed at said working electrode, said first compound being capable in either an oxidized or a reduced form of binding to said phenol analyte, characterized in that said first compound in its oxidized or reduced form comprises a group of structure I R1-NH—C*—(C*—C*)n—C*-QR? (I) (where n is 0 or 1; Q is 0, S, NH or NR?; C*—(C*—C*)n—C* is a two or four carbon string in a conjugated delocalised electron system optionally substituted by a group comprising R; R is an electron-donating or withdrawing substituent; and R? is H or a group R, at le