VİTAMİN TAYİNİ İÇİN YÜZEY PLAZMON REZONANS (SPR) TEMELLİ NANOSENSÖRLERİN HAZIRLANMASI

Abstract

In thesis study, molecularly imprinted surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) nanosensors were prepared for the detection of vitamin B2 (riboflavin), B12 (cobalamin) and B9 (folic acid) vitamins in food samples. Firstly, premonomer complexes were prepared by changing amounts of the monomers, which are the template molecules for B2, B12 and B9 vitamins. The prepared B2, B12 and B9 vitamin:monomer complexes were attached to the gold chip surface of the SPR and QCM nanosensors with UV polymerization. B2, B12 and B9 vitamins imprinted and nonimprinted SPR and QCM nanosensors were characterized by atomic force microscopy (AFM), ellipsometer, scanning electron microscopy (SEM), FTIR-ATR and contact angle measurements. The detection of B2, B9 and B12 vitamins from an aqueous solution was performed using B2, B9 and B12 vitamins imprinted and non-imprinted SPR and QCM nanosensors. In order to detect the kinetic and equilibrium isotherm parameters, SPR and QCM nanosensor data were examined using a kinetic analysis and Scatchard, Langmuir, Freundlich, and Langmuir–Freundlich isotherm models. The selectivity studies for B2, B9 and B12 vitamins imprinted and nonimprinted SPR and QCM nanosensors were tested. The reproducibility of vitamin imprinted SPR and QCM nanosensor was investigated at the same day and different days. The determinations of B2, B12 and B9 vitamins were made from infant formula, growth milk and enteral foods as food samples. Validation studies of the prepared SPR and QCM nanosensors were performed by LC-MS/MS. It was observed that the obtained LC-MS/MS results obtained were consistent with the results of SPR and QCM nanosensors.