A multidentate adsorbate having a bis(carbazolyl) urea unit, as a receptor for hydrogen pyrophosphate anions, and two cyclic bidentate alkyl disulfide groups, as linkers to gold surfaces, has been designed and synthesized. Self-assembled monolayers (SAMs) on gold of this adsorbate have been obtained and characterized showing a high robustness along with an extremely large sensitivity and selectivity for hydrogen pyrophosphate anions enabling to be used as a surface plasmon resonance (SPR) sensor for the detection of such anions at the ppt concentration level under physiological conditions.