Abstract: The present invention relates to a method tor enriching and/or separating and/or immobilizing an analyte of interest comprising bringing an analyte of interest into contact with a derivatizing agent; incubating said analyte with said derivatizing agent, thereby incorporating a sulphonic acid group or as analogue thereof into the molecular structure of mo analyte of interest; bringing the analyte of interest into contact with a molecularly imprinted polymer with selective affinity foe a sulphonic acid group or an analogue thereof; and enriching and/or separating and/or immobilizing the analyte of interest by nee of the molecularly imprinted polymer. Further disclosed is a kit comprising a derivatizing agent, which contains a sulphonic group or an analogue thereof and a reactive group for creating a covalent bond between said derivatizing agent nod an analyte of interest, and a molecularly imprinted polymer with selective affinity for a sulphonic acid group or an analogue thereof.

Abstract: The present invention relates to a method of generating an electron spin resonance enhanced magnetic resonance image of a sample which comprises introducing into the sample a magnetic resonance signal enhancing amount of a free radical and generating an enhanced electron spin resonance image of the sample. The method comprises using as the free radical an inert triarylmethyl free radical, wherein each aryl moiety of said triarylmethyl radical, which may be identical or different, comprises an optionally substituted 6-membered carbocyclic or thienyl ring. The invention also relates to the use of trityls in ESR imaging.