Potentiometric Sensing of Chiral Amino Acids

Abstract

Recognition of enantiomers of amino acids was achieved with potentiometric measurements using chiral sensors constructed by a surface imprinting technique. The sensors exhibited recognition properties toward one isomer of racemic N-carbobenzoxy-aspartic acids (N-CBZ-Asp) without any preseparation processes. The sensors translated the enantioselective recognition event into a potential change by detecting optically active N-CBZ-Asp in a concentration range of 5.0 × 10 -6 -1.2 × 10 -2 M. The enantiomeric selectivity coefficients of the sensors for the counter isomers were in the range of 4.0 × 10 -3 -9.0 × 10 -3 . The sensitivity of these sensors is assigned to the specific surface modification of the electrodes resulting in chiral recognition and to the coupled transduction activity of the sensor.

Synthesis by precipitation polymerization of a molecularly imprinted polymer membrane for the potentiometric determination of sertraline in tablets and biological fluids

“…Despite the relatively simple transduction of the potentiometric signal, only limited reports on the design of the potentiometric sensors have been based on the molecular imprinting technology. These reports describe the dispersion of the MIP particles in the plasticizer and their embedment in a polyvinylchloride (PVC) matrix, [18][19][20][21] the formation of a glassy membrane, 22 the template assembly on the polar surface of the indium tin oxide (ITO) glass plate 23,24 and the deposition of an MIP polymeric film on the gate surface of an ion-sensitive field-effect transistor. 25,26 The prescription of new antidepressant drugs has increased dramatically in the last few years.…”

Carbon Nanotubes – Imprinted Polymers: Hybrid Materials for Analytical Applications

“…MIP-based electrochemical sensors were first reported in the early 1990s by Mosbach's group (Andersson et al, 1990), and to date, remarkable progress in MIP-based electrochemical sensors have been achieved in the use and the performance of conductometric/potentiometric MIP nanomaterials (Zhou Y.X. et al, 2003), which were used to detect many different analytes (Augisto et al, 2010) such as barbituric acid (Mirsky et al, 1999), amino acid derivatives (Panasyuk et al, 1999), morphine , atrazine (Kim Y. et al, 2007), benzyltriphenylphosphonium chloride , thiophenol (Kröger et al, 1999), glutamic acid (Ouyang et al, 2007), folic acid (Prasad et al, 2010a;Prasad et al, 2010c), tolazoline (Zhang Z. et al, 2010a), tryptophan (Prasad et al, 2010d;Kong Y. et al, 2010), clindamycin , 2,4-dichlorophenoxy acetic acid (Xie et al, 2010), histamine (Bongaers et al, 2010) Despite the application of MIPs as sensor matrices or separation materials, they suffer from basic limitations associated with the limited concentration of imprinted sites, and the bulk volume of the polymer matrices that requires long diffusion paths of the imprinted host molecules.…”

Molecularly Imprinted Polymers (PIMs) in Biomedical Applications

“…The capacitance sensors based on MIPs were also fabricated and used to detect many other analytes such as amino acid derivatives with a detection limit of 500 ppm (panasyuk et al, 1999), and barbituric acid with a detection limit of 3.5 ppm . During the past decade, remarkable progress in MIP-based electrochemical sensors have been achieved by the use of conductometric/potentiometric measurements and MIP nanomaterials, greatly extending the range of detected targets and improving the sensitivity, selectivity and simplicity of electrochemical sensors (Zhou et al, 2003). Different MIP sensing device designed with therapeutic application were prepared, by employing amperometric and/or voltammetry measurements and using several different templates, such as morphine, , atrazine (Kim et al, 2007), benzyltriphenylphosphonium chloride , thiophenol (Kröger et al, 1999), glutamic acid (Ouyang et al, 2007).…”