Influence of the intramolecular hydrogen bonding on imprinting and its modelling study

What is it about?

This work proposes the synthesis of highly efficient chitosan based Molecularly Imprinted Polymer (MIP) for removal of salicylic acid (SA). In this study, 4 Hydroxy benzoic acid (4HBA) was used as dummy template during imprinting, as strong intramolecular hydrogen bonding in salicylic acid can imparts poor imprinting effect. Molecular modeling studies were performed to evaluate the effect of intramolecular hydrogen bonding of SA on template monomer interaction. Interaction between 4HBA-CTS was stronger as compared to SA-CTS leading to better imprinting. Suspension polymerisation method was used for synthesis of MIP in beaded form. Here paraffin oil was used as a continuous phase which helps in preserving noncovalent interaction between chitosan and 4HBA, resulting in the formation of stable prepolymerisation complex without any stabilizer or initiator. One of the most important features of this work is that chitosan; an abundant biopolymer was used as functional polymer instead of synthetic monomer making overall process cost effective and ecofriendly. Keywords: - MIP, SA, 4HBA, OPECs, Molecular Modeling, Chitosan.

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Why is it important?

SA is a prominent metabolite of aspirin (acetylsalicylic acid, ASA), which is widely used as an analgesic, for the prevention of heart attack, in keratolytic and dermatitis treatment and also as a preservative in the food items. In the United States alone, approximately 20,000 million tablets of Aspirin are consumed annually. SA can enter into the aquatic environment through various sources such as the pharmaceutical industry, human and veterinary drugs, paper and cosmetic industries, use of activated sludge from wastewater treatment plant for agricultural purpose. SA has been classified as “Organic pollutants of emerging concern” (OPECs) due to their toxic effect on living organisms. Primary and secondary stages in sewage treatment plant are incapable of completely degrading or removing OPECs. Often, the treated or untreated municipal/domestic wastewater is used for irrigation, which further contaminates the underground and surface water. Therefore, removal of SA from water bodies is necessary for environmental application.

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