Selective determination of monosodium glutamate (Ajinomoto) in food samples using a potentiometric method with a modified multiwalled carbon nanotube based molecularly imprinted polymer

Abstract

The aim of the present work was to test the use of a surface modified multi-walled carbon nanotube based molecularly imprinted polymer (MWCNT-MIP) for the selective identification of monosodium glutamate (MSG) in food samples. The hydroxylated MWCNTs were reacted with allyl bromide to form vinylated MWCNTs (MWCNT-CHCH₂). The MWCNT-MIP was synthesized by selective polymerization of MWCNT-CHCH₂ with itaconic acid (IA) as the functional monomer in the presence of MSG using ethylene glycol dimethacrylate (EGDMA) as a cross-linker and α,α′-azobisisobutyronitrile (AIBN) as the initiator. The organized material was characterized using different instrumental techniques. The proposed sensor has a response time of ∼1 min and the calculated detection limit for MSG was 1.0 × 10⁻⁹ mol L⁻¹. The sensitivity obtained for the MWCNT-MIP sensor is 56 mV per decade. The linear range obtained for the sensor is 10⁻⁹ to 10⁻⁵ mol L⁻¹. The MWCNT-MIP sensor membrane is an effective tool for the identification of MSG in food samples.