title: Highly sensitive and selective hyphenated technique (molecularly imprinted polymer solid-phase microextraction-molecularly imprinted polymer sensor) for ultra trace analysis of aspartic acid enantiomers.
abstract: The present work is related to combination of molecularly imprinted solid-phase microextraction and complementary molecularly imprinted polymer-sensor. The molecularly imprinted polymer grafted on titanium dioxide modified silica fiber was used for microextraction, while the same polymer immobilized on multiwalled carbon nanotubes/titanium dioxide modified pencil graphite electrode served as a detection tool. In both cases, the surface initiated polymerization was found to be advantageous to obtain a nanometer thin imprinted film. The modified silica fiber exhibited high adsorption capacity and enantioselective diffusion of aspartic acid isomers into respective molecular cavities. This combination enabled double preconcentrations of d- and l-aspartic acid that helped sensing both isomers in real samples, without any cross-selectivity and matrix complications. Taking into account 6×10(4)-fold dilution of serum and 2×10(3)-fold dilution of cerebrospinal fluid required by the proposed method, the limit of detection for l-aspartic acid is 0.031ngmL(-1). Also, taking into account 50-fold dilution required by the proposed method, the limit of detection for d-aspartic acid is 0.031ngmL(-1) in cerebrospinal fluid.
authors: Analytical Division, Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005, India. prof.bbpd@yahoo.com
authors: Bhim Bali
authors: BB
authors: Prasad
authors: Amrita
authors: A
authors: Srivastava
authors: Mahavir Prasad
authors: MP
authors: Tiwari
mesh_terms: D000327:Adsorption; D001224:Aspartic Acid / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid / Q000737:chemistry*; D002853:Chromatography, Liquid; D006108:Graphite / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D013058:Mass Spectrometry; D008855:Microscopy, Electron, Scanning; D054802:Molecular Imprinting / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D015203:Reproducibility of Results; D012822:Silicon Dioxide / Q000737:chemistry; D052617:Solid Phase Microextraction / Q000379:methods*; D013237:Stereoisomerism; D013499:Surface Properties
chemical_list: D037742:Nanotubes, Carbon; D011108:Polymers; D001224:Aspartic Acid; D012822:Silicon Dioxide; D006108:Graphite