Physostigmine salicylate is a carbamate drug acting as reversible acetylcholinesterase (AChE) inhibitor [1]. The presence in the waste water of drug residues which act as AChE inhibitor is a major problem due to their potential toxicity toward humans and animals and therefore a sensitive and fast detection method is of great importance. Only few amperometric biosensors are reported in literature for carbamate drug detection and most of them are bi-enzymatic, based on the coimmobilization of two enzymes, AChE and choline oxidase (ChO) [2]. One possible way to bypass the use of two enzymes is the use of thiocoline, the non-natural substrate of AChE. The inhibition degree of AchE can be monitored by the oxidation of enzymatically generated thiocoline (TCh). On unmodified electrodes TCh is oxidised at very high potentials (+700 mV vs Ag/AgCl) and for these reasons various mediators have been used in order to reduce the overpotential as well as problems of surface passivation [3]. In this work, a novel monoenzymatic biosensor for physostigmine detection was developed based on a screen-printed electrode (SPE) modified with a stable dispersion of cobalt phthalocyanine and commercially available carbon black (CB). This probe showed significantly enhanced electrochemical activity relative to a bare SPE towards TCh allowing amperometric detection of TCh at very low applied potentials (+50 mV vs Ag/AgCl) with a linearity range from 0.03 to 0.08 mM and a detection limit of 0.01 mM. The modified SPE was, then, used as substrate for the immobilization of AChE. We found a kM app for acethlthiocholine of 0.28 ± 0.05 mM, in good agreement with the KM (0.20-0.22 mM) determined for the free enzyme in solution [4]. Analytical parameters such as mediator and enzyme concentration, substrate concentration and incubation time for reversible inhibition of physostigmine were studied in order to optimize and improve the elecrochemical performances of the biosensor. Under optimum conditions, the physostigmine biosensor showed a very low detection limit (0.8 nM), good reproducibility and stability. It is, therefore, suitable for future trace detection of physostigmine residue in wastewaters. [1] I.B. Wilson, M.A. Harrison, S. Ginsburg, 1961, J. Biol. Chem., 1961, 236, 1498-1500. [2] M. LeDoux, J, Chrom. A, 2011, 1218, 1021-1036. [3] F. Arduini, A. Cassisi, A. Amine, F. Ricci, D. Moscone, G. Palleschi, J. Electroanal. Chem. 2009, 626, 66-74. [4] F. Ricci, F. Arduini, C.S. Tuta, U.Sozzo, D. Moscone, A.Amine, G. Palleschi, Anal. Chim. Ata, 2006, 558, 164- 170.
Monoenzymatic amperometric biosensor for fhysostigmine detection based on screen-printed electrode modified with cobalt phtalocyanine-carbon black nanocomposite / Antiochia, Riccarda; Arduini, Fabiana; Neagu, Dana; Palleschi, Giuseppe; Carbone, Marilena. - STAMPA. - (2014). (Intervento presentato al convegno 15th International Conference on Electroanalysis (ESEAC) tenutosi a Malmo, Svezia nel 11-15 Giugno 2014).
Monoenzymatic amperometric biosensor for fhysostigmine detection based on screen-printed electrode modified with cobalt phtalocyanine-carbon black nanocomposite
ANTIOCHIA, RICCARDA;
2014
Abstract
Physostigmine salicylate is a carbamate drug acting as reversible acetylcholinesterase (AChE) inhibitor [1]. The presence in the waste water of drug residues which act as AChE inhibitor is a major problem due to their potential toxicity toward humans and animals and therefore a sensitive and fast detection method is of great importance. Only few amperometric biosensors are reported in literature for carbamate drug detection and most of them are bi-enzymatic, based on the coimmobilization of two enzymes, AChE and choline oxidase (ChO) [2]. One possible way to bypass the use of two enzymes is the use of thiocoline, the non-natural substrate of AChE. The inhibition degree of AchE can be monitored by the oxidation of enzymatically generated thiocoline (TCh). On unmodified electrodes TCh is oxidised at very high potentials (+700 mV vs Ag/AgCl) and for these reasons various mediators have been used in order to reduce the overpotential as well as problems of surface passivation [3]. In this work, a novel monoenzymatic biosensor for physostigmine detection was developed based on a screen-printed electrode (SPE) modified with a stable dispersion of cobalt phthalocyanine and commercially available carbon black (CB). This probe showed significantly enhanced electrochemical activity relative to a bare SPE towards TCh allowing amperometric detection of TCh at very low applied potentials (+50 mV vs Ag/AgCl) with a linearity range from 0.03 to 0.08 mM and a detection limit of 0.01 mM. The modified SPE was, then, used as substrate for the immobilization of AChE. We found a kM app for acethlthiocholine of 0.28 ± 0.05 mM, in good agreement with the KM (0.20-0.22 mM) determined for the free enzyme in solution [4]. Analytical parameters such as mediator and enzyme concentration, substrate concentration and incubation time for reversible inhibition of physostigmine were studied in order to optimize and improve the elecrochemical performances of the biosensor. Under optimum conditions, the physostigmine biosensor showed a very low detection limit (0.8 nM), good reproducibility and stability. It is, therefore, suitable for future trace detection of physostigmine residue in wastewaters. [1] I.B. Wilson, M.A. Harrison, S. Ginsburg, 1961, J. Biol. Chem., 1961, 236, 1498-1500. [2] M. LeDoux, J, Chrom. A, 2011, 1218, 1021-1036. [3] F. Arduini, A. Cassisi, A. Amine, F. Ricci, D. Moscone, G. Palleschi, J. Electroanal. Chem. 2009, 626, 66-74. [4] F. Ricci, F. Arduini, C.S. Tuta, U.Sozzo, D. Moscone, A.Amine, G. Palleschi, Anal. Chim. Ata, 2006, 558, 164- 170.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
