Ultratrace analysis of uracil and 5‐fluorouracil by molecularly imprinted polymer brushes grafted to silylated solid‐phase microextraction fiber in combination with complementary molecularly imprinted polymer‐based sensor

Abstract

Main inborn errors of metabolism diagnosable through uracil (Ura) analysis and the therapeutic monitoring of toxic 5-fluorouracil (5FU) in dihydro pyrimidine dehydrogenase (DPD) deficient patients require a sensitive, reproducible, selective and accurate method. In this work, an artificial receptor in the format of molecularly imprinted polymer (MIP) brush 'grafted to' the surface of sol-gel immobilized on cost-effective homemade solid-phase microextraction (SPME) fibers, individually imprinted with either of Ura and 5FU, was used in combination with a voltammetric sensor duly modified with the same MIP. This combination provided up to 10- and 8.4-fold preconcentrations of Ura and 5FU, respectively, which was more than sufficient for achieving stringent detection limits in the primitive diagnosis of uracil disorders and fluoropyrimidine toxicity in DPD-deficient patients. The proposed method permits the assessment of Ura and 5FU plasma concentrations with detection limits pf 0.0245 and 0.0484 ng mL(-1) (RSD = 1.0-2.5%, S/N = 3), respectively, without any problems of non-specific false-positives and cross-reactivities in complicated matrices of biological samples.

A Critical Review on Clinical Application of Separation Techniques for Selective Recognition of Uracil and 5-Fluorouracil

“…This MISPME hyphenated with MIP-sensor method revealed nanomolar concentrations with a limit of detection (LOD) of 0.0245 ng ml -1 for Ura, without any false positives [11].…”

“…The SPME analysis of Ura is highly scarce. So far, two SPME analyses-one for substituted Ura Human plasma MISPME-MIP sensor Poly(melamine-co-chloranil) SPME-fiber LOD: 0.0245 [11] Human plasma SPE microcolumns and TLC Adsorbex SPE - [17] LOQ limit of quantification, LOD limit of detection * Recoveries of Ura # Concentrations of 5-FU converted to ng mL -1 for comparison Ind J Clin Biochem (Jan-Mar 2016) 31(1): 3-12 5 pesticides [18] and other for substituted Ura herbicide [19] have been reported.…”

“…Ura recognition was also made possible by using molecularly imprinted copolymer membranes [23]. Latter, MIPs were synthesized by using acrylonitrile (AN) co-polymers, poly (AN-co-MAA) and Human plasma MISPME-MIP senor Poly(melamine-co-chloranil) SPME-fiber 0.0484 [11] Human serum Reversed phase chromatography with UV detection poly (AN-co-AA), with methacrylic acid (MAA) and acrylic acid (AA) for phase inversion imprinting of Ura [24]. The imprinted poly (AN-co-MAA) membrane could bind 7.9 lmol/g of Ura with 8.4 9 10 -6 m 3 /m 2 s of volume flux.…”

“…The developed nanostructured Ura imprinted polymer shows highly specific and selective monolayer coverage of Ura on the EGDMA-crosslinked MAA polymer [30]. Although several MIPs for Ura have been reported, only one of them applied as chromatographic material [4] and another as SPME material [11]. This was primarily due to the sensitivity and non-specific complications which are yet to be resolved.…”

“…It was observed that MIP selectively recognized 5-FU via hydrogen bindings exclusively, when applied, both as a solid phase microextraction coatings as well as a sensitive conducting film on electrode, and achieved nanomolar detection range from 0.14 to 80.0 ng mL -1 (LOD: 0.0484 ng mL -1 ) for 5-FU analysis, without any matrix interferences [11].…”