This paper describes the synthesis of novel molecularly imprinted polymers (MIPs), prepared by a noncovalent imprinting approach, for cleanup and preconcentration of curcumin (CUR) and bisdemethoxycurcumin (BDMC) from medicinal herbal extracts and further analysis by high-performance liquid chromatography with fluorescence detection (HPLC-FLD). Two molecular mimics, a mixture of reduced BDMCs and 4-(4-hydroxyphenyl)-2-butanone (HPB), have been synthesized and applied as templates for MIP synthesis. The polymers were prepared using N-(2-aminoethyl) methacrylamide (EAMA) as functional monomer, ethylene glycol dimethacrylate (EDMA) as the cross-linker (in a 1:5 molar ratio), and a mixture of acetonitrile/dimethylsulfoxide (90%, v/v) as porogen. MIPs prepared using a mixture of reduced BDMCs as template showed higher selectivity for CUR and BDMC than those obtained with HPB, with imprinting factors of 3.5 and 2.7 for CUR and BDMC, respectively, using H2O/acetonitrile (65:35, v/v) as mobile phase. The adsorption isotherms for CUR in the MIP and the nonimprinted polymer (NIP) were fitted to the Freundlich isotherm model, and the calculated average binding affinities for CUR were (17 ± 2) and (8 ± 1) mM(-1) for the MIP and the NIP, respectively. The polymers were packed into solid-phase extraction (SPE) cartridges, and the optimized molecularly imprinted solid-phase extraction (MISPE-HPLC) with fluorescence detection (FLD) method allowed the extraction of both curcuminoids from aqueous samples (50 mM NH4Ac, pH 8.8) followed by a selective washing with acetonitrile/NH4Ac, 50 mM at pH 8.8 (30:70%, v/v), and elution with 3 × 1 mL of MeOH. Good recoveries and precision ranging between 87 and 92%, with relative standard deviation (RSD) of <5.3% (n = 3), were obtained after the preconcentration of 10-mL solutions containing both CUR and BDMC at concentrations in the range of 0-500 μg L(-1). The optimized method has been applied to the analysis of both curcuminoids in medicinal herbal extracts.

ABSTRAKKontaminasi logam berat pada lingkungan perairan merupakan masalah besar dunia saat ini. Logam berat tidak dapat diurai atau dimusnahkan dan merupakan zat pencemar kimiawi. Cu(II) adalah logam berat yang bersifat racun jika masuk kedalam tubuh. Metode analisis Cu(II) sudah banyak dikembangkan salah satunya dengan teknik injeksi alir. Metode analisis ini memiliki waktu analisis yang singkat namun menggunakan pelarut yang mahal, faktor prakonsentrasi yang rendah, dan memiliki selektivitas yang rendah pula untuk ion Cu(II). Oleh karena itu, untuk meningkatkan selektivitas dilakukan pengembangan metode ekstraksi fasa padat menggunakan polimer pengkelat yaitu Ion Imprinted polymer (IIPs). Pada penelitian ini, Cu-IP berhasil disintesis melalui polimerisasi thermal menggunakan asam salisilat dan formaldehida dengan ligan pengkelat 4-(2-pyridylazo)recorcinol dengan pemanasan selama 10 jam pada temperatur 500C , menggunakan HCl sebagai katalis. Perbandingan stoikiometri kompleks biner Cu(II):PAR dibuat dengan perbandingan mol 1:1 yang dihitung dengan metode job. Kapasitas adsorpsi maksimum teramati pada konsentrasi 10 ppm dengan pH 6 dan waktu kontak 80 menit. IIP digunakan untuk prakonsentrasi adsorpsi dan desorpsi dengan persen perolehan kembali sebesar 97,09 % untuk IIP dan 53,11 % untuk NIP. Faktor prakonsentrasi yang diperoleh pada sampel lingkungan sebesar 1,85. Dengan hasil percobaan tersebut Cu-IP terbukti sebagai polymer fungsional dengan selektivitas dan regenerasi tinggi.

Band structure of polymer extracted from oligomer calculations by elongation method and its applications to nanosystems AIP Conf.Abstract. Molecularly Imprinted Polymers (MIPs) for the selective recognition properties of curcumin (CUR), a cancer chemopreventive agent were obtained by a non-covalent imprinting approach with bisdemetoxycurcumin (BDMC) as the template molecule. The double bond of BDMC has been reduced in order not to be involved in polymerization and make the template molecules easy to be eluted. Several functional monomers have been evaluated to maximize the interactions with the template molecule during polymerization. MIPs prepared by bulk of N-(2-aminoethyl) metacrylamid hydrochlorideas functional monomer, ethylene glycol dimethacrylate as crosslinker, 2,2'-azobis (2'4-dimethyl valeronitril) as initiator and acetonitrile as porogen. Non-imprinted polymer (NIP) have been also synthesized for reference purposes. UV-vis spectroscopy has been used to predict the template to functional monomer ratio which indicates the formation of 2:1 complexes between monomer and curcumin and the association constants (K 11 = 2529 μM and K 12 = 1960.75 μM in acetonitrile). The capacity and imprinting factor have been evaluated as stationary phases in high-pressure liquid chromatography to CUR and BDMC. The binding properties and the homogeneity of the binding sites of the different polymers have been studied by Freundlich isotherm modeling and weight average affinity and number of binding sites. One of the foremost applications of molecular imprinting has been in molecularly imprinted solid phase extraction and it has the ability to separate and preconcentrate between closely related compounds in curcuminoids.