title: Molecularly imprinted polymer-matrix nanocomposite for enantioselective electrochemical sensing of D- and L-aspartic acid.
abstract: A new molecularly imprinted polymer-matrix (titanium dioxide nanoparticle/multiwalled carbon nanotubes) nanocomposite was developed for the modification of pencil graphite electrode as an enantioselective sensing probe for aspartic acid isomers, prevalent at ultra trace level in aqueous and real samples. The nanocomposite having many shape complementary cavities was synthesized adopting surface initiated-activators regenerated by electron transfer for atom transfer radical polymerization. The proposed sensor has high stability, nanocomposite uniformity, good reproducibility, and enhanced electrocatalytic activity to respond oxidative peak current of L-aspartic acid quantitatively by differential pulse anodic stripping voltammetry, without any cross-reactivity in real samples. Under the optimized operating conditions, the L-aspartic acid imprinted modified electrode showed a wide linear response for L-aspartic acid within the concentration range 9.98-532.72 ng mL(-1), with the minimum detection limit of 1.73-1.79 ng mL(-1) (S/N=3) in aqueous and real samples. Almost similar stringent limit (1.79 ng mL(-1)) was obtained with cerebrospinal fluid which is typical for the primitive diagnosis of neurological disorders, caused by an acute depletion of L-aspartic acid biomarker, in clinical settings.
authors.affiliation: Analytical Division, Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005, India. prof.bbpd@yahoo.com
authors.forename: Bhim Bali
authors.initials: BB
authors.lastname: Prasad
authors.forename: Amrita
authors.initials: A
authors.lastname: Srivastava
authors.forename: Mahavir Prasad
authors.initials: MP
authors.lastname: Tiwari
mesh_terms: D000081:Acetamides / Q000737:chemistry; D001224:Aspartic Acid / Q000032:analysis* / Q000134:cerebrospinal fluid / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006801:Humans; D054802:Molecular Imprinting; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D037742:Nanotubes, Carbon / Q000737:chemistry / Q000648:ultrastructure; D011108:Polymers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism; D014025:Titanium / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000081:Acetamides; D037742:Nanotubes, Carbon; D011108:Polymers; D014867:Water; C009495:titanium dioxide; D001224:Aspartic Acid; D014025:Titanium
keywords: Differential pulse anodic stripping voltammetry; Enantioselectivity; Molecularly imprinted polymer-matrix nanocomposite; d- and l-aspartic acid