Compounds of the formula (I) ##STR1## in which Q.sup.1 and Q.sup.2 are each OH or form a trimeric boric anhydride, Z is CHO, CH.sub.2 Y, X or a protected aldehyde group, and X is CN, COOH, COCl, CONH.sub.2 or C(OR).sub.3, and Y is OH or NH.sub.2, and Z is in the o-, m- or p-position to the boronic acid radical, are prepared by a) reacting a compound of the formula (II) ##STR2## with Mg in the presence of an anthracene compound and, if desired, a transition-metal halide and, if desired, an Mg halide or in the presence of a transition-metal halide and, if desired, an Mg halide, to give the corresponding arylmagnesium chloride, b) reacting the latter with a borate of the formula B(OR').sub.3 and hydrolyzing the product, with removal of the aldehyde protecting group, c) and, if desired, oxidizing or reducing the free aldehyde group.

The invention provides a kit for a glycated haemoglobin assay, said kit comprising: a porous membrane capable of retaining precipitated haemoglobin; a first reagent comprising zinc ions in aqueous basic solution or comprising a water soluble zinc compound; a second reagent comprising a chromophore-boronic acid conjugate; and optionally, an aqueous washing reagent; wherein at least one of the first and second reagents further comprises a surfactant capable of lysing erythrocytes, and wherein said second reagent if liquid is acidic.

Compositions and methods for determining the presence or concentration of an analyte in a sample by exposing the sample to an indicator molecule comprising a fluorescent lanthanide metal chelate complex. The presence or concentration of the analyte in the sample is determined by observing and/or measuring the change in intensity of fluorescence emitted by the lanthanide metal chelate complex upon binding of the analyte to one or more recognition elements in the complex. The fluorescent indicator molecules can be used in various types of fluorescent sensing devices and are useful in various fields, including energy, medicine and agriculture.

This invention relates to a test element and a method for determining the ratio of glycated to non-glycated haemoglobin in a sample, for example, in a blood sample that is provided as a fresh sample, a dried sample or a haemolysed sample. The test element can include different zones for receiving the sample, serving as a depot for reagents such as non-immobilized signal-generating molecules or haemolysis reagents, separating reagents from the sample, and detecting heamoglobin. The zones are provided on a porous matrix and in fluid contact with each other. The method uses the test element and determines the ratio of glycated to non-glycated haemoglobin in a sample, by contacting the sample with an excess of signal generating molecules to bind to the glycated haemoglobin. The non-bound signal generating molecules are separated from the sample, and the amount or concentration of haemoglobin and/or glycated haemoglobin bound signal generating molecules are determined. The signal generating molecules can be selected to be a direct label, an enzyme label or a radiolabel, which can be attached to the glycated haemoglobin via a boronic acid group or another specific binding partner or antibody.

This invention relates to a method for determining the ratio of glycated to non-glycated haemoglobin in a sample. The method includes contacting the sample with an excess of signal generating molecules to bind to the glycated haemoglobin. The non-bound signal generating molecules are separated from the sample, and the amount or concentration of haemoglobin and the glycated haemoglobin bound signal generating molecules are determined.