An optical fiber aspirin sensor with molecularly-imprinted polymer coating on fiber core surface as transducer

• Integrating molecularly-imprinted polymer with fiber optic chemical sensor. • MIP microextraction/fiber optic spectrometric detection in a single fiber probe. • MIP microextraction improves sensor’s sensitivity by 2583 times. • MIP selective extraction improve sensor’s selectivity. • Green sensor technique, no chemical reagent needed for the detection. An optical fiber chemical sensor for detecting acetylsalicylic acid (ASA) in aqueous sample solutions has been developed by using an ASA imprinted Chitosan membrane coated on an optical fiber surface as a transducer. The integration of molecularly imprinted polymer (MIP) membrane as an optical fiber chemical sensor’s transducer significantly improved sensor’s selectivity. In addition, Chitosan is a basic polymer, contains an amine group in each of its glucose ring. ASA is a weak acid. The weak acid/base reaction concentrates ASA from sample solution into MIP membrane and significantly improve the sensor’s sensitivity. Compared with a bare optical fiber probe for detecting ASA, the sensor of this work achieved a 2583 times sensitivity improvement due to the function of concentrating ASA from sample solution into the MIP membrane. The sensor achieved a detection limit of 0.069 µg/mL, which is 5–10 time lower when compared with traditional UV/Vis optical absorption spectrometric methods for detecting ASA. This sensor detects ASA’s intrinsic optical absorption spectrum as a sensing signal, and no additional reagent is needed for detecting ASA in a sample solution. The sensor’s response to ASA is reversible because the adsorption of ASA into the MIP is a reversible process. The sensor has a fast response with response time of 2 min. The sensor has been used for analyzing ASA in an aspirin drug product available from a local pharmacy store. Analytical result obtained with the developed sensor agrees well with that obtained by using a traditional UV/Vis optical absorption spectrometric method.