Influence of polymer composition on the sensitivity towards nitrite and nitric oxide of colorimetric disposable test strips

摘要

The influence of polymer composition on thesensitivity towards nitrite (NO2−) and nitric oxide (NO)of a series of 19 polymeric hydrogel films has been stud-ied. The polymers, based on the hydrophilic monomer 2-hydroxyethylmethacrylate (HEMA), are able to encapsu-late the colorimetric indicator 1,2-diaminoanthraquinone(DAQ) and to respond to NO2−and NO by visual chang-es. In the case of nitrite, the calculated limits of detection(LOD) for two of the polymeric sensors (10μM) arevery close to the sensitivity estimated for free DAQ insolution (LOD 5μM), but with the advantage of a solidsupported sensor with the format of a disposabletest-stripmade with affordable starting chemicals. The re-sults are interpreted takinginto account the nature andproportions of monomers and cross-linkers used for thesynthesis of polymers. Key factors for obtaining sensi-tive materials are the hydrophilic character of the filmalong with the utilization of low levels of cross-linkerand the use of an acidic monomer, like acrylic acid, asa building block.