Untitled

Abstract

A molecularly imprinted polymer which recognises the mycotoxin ochratoxin A was prepared using the mimic N-(4-chloro-1-hydroxy-2-naphthoylamido)-(L)-phenylalanine as a template. The polymer was obtained by dissolving the template, methacrylic acid and ethylendimethacrylate in chloroform and polymerising the mixture by thermal treatment at 60 degrees C. The monolith obtained was crushed, sieved to 30-90 microm and extensively washed till the template could no longer be found in the washing solution. The binding properties towards the template, ochratoxin A and several related molecules were measured by eluting with acetonitrile and chloroform a HPLC column packed with the imprinted polymer. The experimental results show that the polymer recognises not only the template well, but also the ochratoxin A. The specific molecular recognition effect is due to hydrogen bond interactions but in order to assure the full recognition effect adjunctive steric factors are necessary. The magnitude of these interactions can be controlled by the use of limited amounts of acetic acid in the mobile phase. From the measurement of the relative selectivity it was found that only the simultaneous presence of the carboxyl, the phenolic hydroxyl and certain peculiar substructures such as the chlorine atom assures the whole recognition of the template.

Molecular imprinted polymers as synthetic receptors for the analysis of myco- and phyco-toxins

“…In fact, in 2001, the same synthetic approach -with minimal differences -was independently reported by our group 30 and Maier et al 31 . As previously described, a good mimic template was rationally designed to preserve the general structure of the target analyte, including the chirality of the amino acidic sub-structure and the planarity of the An imprinted polymer prepared by using OTA directly as a template molecule is described by Turner et al 32 .…”

“…This is the case for the preparation of an imprinted polymer for the recognition of the mycotoxin ochratoxin A (5) 30 . A good mimic template should preserve the general structure of the target analyte, including the chirality of the amino acidic sub-structure and the planarity of the benzopiranic sub-structure.…”

Effect of the mimic structure on the molecular recognition properties of molecularly imprinted polymers for ochratoxin A prepared by a fragmental approach

“…Acetic acid, L-alanine, 2,2'-azobis-(2-methylpropionitrile) (AIBN), N,N-dicyclohexylcarbodiimide, glycine, L-phenylalanine and all the organic solvents were from VWR International (Milan, Italy). 4-Chloro-1-hydroxy-2-naphthoic acid was prepared from the commercially available 1-hydroxy-2-naphthoic acid in according to the procedure previously reported in literature [6].…”

“…In the past, several examples of MIPs binding the mycotoxin Ochratoxin A (OTA, 1) have been published [6][7][8], and this mycotoxin has been frequently considered as target analyte for MISPE of complex samples [9][10][11][12][13][14][15]. When taken into consideration, the problem of polymer bleeding has been successfully addressed by using the rationally designed mimic N-(4-chloro-1-hydroxy-2-naphthoylamido)-(L)-phenylalanine (CHNA-Phe, 3) as a template molecule [6].…”

“…When taken into consideration, the problem of polymer bleeding has been successfully addressed by using the rationally designed mimic N-(4-chloro-1-hydroxy-2-naphthoylamido)-(L)-phenylalanine (CHNA-Phe, 3) as a template molecule [6]. Notwithstanding its success, the use of CHNA-Phe as a mimic poses the problem of its synthesis.…”