Preparation of guanidinium terminus-molecularly imprinted polymers for selective recognition and solid-phase extraction (SPE) of [arginine]-microcystins

Abstract

About 70 % of microcystin (MC) congeners reported in literature consist of L-arginine amino acid (R) with its guanidinium terminal extending out of the cyclic moiety of these MCs. Molecularly imprinted polymer (MIP) bearing guanidinium terminus cavities was successfully synthesised using L-arginine as a template. Non-imprinted polymer (NIP; without template) was also synthesised for control purposes. The surface area, total pore volume and average pore diameter of MIP and NIP were 267.13 m(2)/g, 0.63 cm(3)/g and 88.39 Å; 249.39 m(2)/g; 0.54 cm(3)/g and 87.14 Å, respectively. The polymers were investigated for selective recognition and extraction of [arginine]-MCs in water using solid-phase extraction/liquid chromatography-electrospray ionisation-mass spectrometry (SPE/LC-ESI-MS) method. Representative model standard solutions (0.5-10.0 μg/L) of MC-LR and MC-LY were spiked in distilled water, recovered by SPE and quantified by LC-ESI-MS. In this study, Oasis Waters™ HLB cartridges served as positive control SPE sorbents. The MIP recognised MC-LR with high recoveries (70.8-91.4 %; r(2) = 0.9962) comparable to HLB cartridges (71.0-91.85 %; r(2) = 0.9993), whereas the NIP did not recognise or retain MC-LR. Also, neither MIP nor NIP recognised or retained MC-LY. Extracts of environmental toxic Microcystis aeruginosa were subjected to SPE procedure employing MIP, NIP and HLB cartridges. Microcystin-LR, -YR, -RR, -WR, -(H4)YR and (D-Asp(3), Dha(7))MC-RR were extracted by MIP and HLB cartridges only as confirmed by LC-ESI-MS. This study demonstrated that the prepared MIP have potential applications for the removal in water and LC-ESI-MS identifications of MCs consisting the guanidinium moiety, i.e.[arginine]-MCs, and in particular targeting commonly encountered toxic congeners, MC-LR, -YR and -RR.

Recent advances in molecularly imprinted polymers in food analysis

“…The results show that the developed extraction protocol eliminated the effect of template leakage on quantitative analysis and could be applied for the determination of PAEs in complicated functional beverages products. With regard to high cost and/or rare targets, the use of fragments, called fragment imprinting, seems to be an effective method in which only a part of the target molecule is used as the template, 187,188 as depicted in Scheme 5. 188 It should be noted that the recognition in a water sample is highly needed because most food samples are related to aqueous media.…”

Two‐Fragment‐Dummy‐Template Molecularly Imprinted Polymers Mn Doped ZnS Quantum Dots Based Room‐Temperature Phosphorescene Probing for Hepatotoxic Homologues of Microcystin

“…Molecular imprinting is a promising technique for synthesizing porous materials with specific recognition sites toward a certain kind of molecule. [19] Molecularly imprinted polymers (MIPs) own the advantages of high selection, easy preparation, good chemical stability and low cost, [20] and has been widely used in chemical sensing, [21][22][23][24] photodegradation and separation. [25][26][27] However, the traditional MIPs also have some disadvantages, such as difficulty to completely remove the template, leakage of template molecules and slow mass transfer.…”

“…According to the analysis of the structure of MCs-LR, MCs-RR and MCs-YR, these MCs contain important two fragment including L-arginine and a rare amino acid, 3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (ADDA). [19,34] Kubo etal synthesized MIPs for the recognition of ADDA and glutamate groups in MCs using a fragment imprinting approach to enrichment of MC. [34] However, the synthesis of ADDA is complex and need several steps.…”

“…Due to complex structures, extreme toxicity and high price of microcystins, how to choose an alternative template is a big problem to avoid the template leakage. According to the analysis of the structure of MCs–LR, MCs‐RR and MCs‐YR, these MCs contain important two fragment including L‐arginine and a rare amino acid, 3‐amino‐9‐methoxy‐2,6,8‐trimethyl‐10‐phenyldeca‐4,6‐dienoic acid (ADDA) . Kubo etal synthesized MIPs for the recognition of ADDA and glutamate groups in MCs using a fragment imprinting approach to enrichment of MC .…”

Microcystin-LR Enrichment from Freshwater by a Recombinant Plant-derived Antibody Using Sol-Gel-Glass Immunoextraction

“…L-arginine, as the template molecule. 32 The main disadvantage is demand for a large amount of template to synthesize a bulk quantity of polymer. So far, only one paper has reported the application of MIPs for the removal of MC-LR from surface water in a lab-scale experiment.…”