Adsorption-controlled preparation of molecularly imprinted hybrid composites for selective extraction of tetracycline residues from honey and milk

Abstract

Molecularly imprinted organic-inorganic hybrid composite materials (MIP-HCMs) with controlled swelling and adsorption properties were prepared through copolymerization and the sol-gel process by using doxycycline (DC) as the template molecule, methacrylic acid (MAA) as a functional monomer, methacryloxypropyltrimethoxysilane (KH-570) as a coupling agent and TEOS as an inorganic precursor. By means of changing polymerization conditions as well as the copolymerization ratio of the inorganic precursor and the organic functional monomer, the properties of sorbents can be adjusted for different needs.So the effect of preparation conditions on the structure of the material was studied. The polymer group, thermal stability, adsorption and selectivity characteristics, and the volume swelling degree of the MIP-HCMs were characterized by FTIR, TGA, and dynamic adsorption and swelling experiments, respectively.It was observed that the MIP-HCMs exhibited the highest selectivity (4.9), maximum adsorption capacity (58.2 mg g À1 ) and good thermal stability. The obtained MIP-HCM was used as an adsorbent for solid-phase extraction of tetracyclines from the milk and honey samples. The average recoveries of three tetracycline antibiotics (DC, tetracycline and chlortetracycline) were obtained in the range of 74.7-115.5% with the precision of 2.1-4.9%. The limits of detection and quantitation of the proposed method were in the range of 4.9-15.3 mg kg À1 and 16.6-51.0 mg kg À1 for the milk samples, and 8.3-15.1 mg kg À1 and 18.3-50.2 mg kg À1 for the honey samples, respectively.

Preparation and Characterization of Sulfonic Acid Functionalized Silica and Its Application for the Esterification of Ethanol and Maleic Acid

“…A band observed at 1472 cm -1 in SAFS is assigned to bending vibrations of methylene group, an indication of association of 3MPTMS to SiO 2 molecule. More intense band at 2980 and 2888 cm -1 in SAFS were due to C-H symmetric and asymmetric stretching vibrations of propyl chain attached to the silica framework [34,35]. These changes in the FTIR spectra of SG and SAFS are the indications of interaction between SG, 3MPTMS and sulfuric acid.…”

Methods for the separation, preconcentration, and determination of tetracycline antibiotics

“…SPE was used in the determination of tetracyclines in meat [15,19,21,22], fish [28-30, 45, 58], eggs [59,68], honey [34,35,37,69], and milk [33,[70][71][72][73][74][75][76][77][78][79][80]. In the case of milk, SPE was carried out in the majority of cases after the precipitation of proteins by trichloroacetic acid [70,75,77] or buffer solutions [33, 71-74, 79, 80].…”

“…The following commercial cartridges also found use: Strata XL [15], Strata C18 E [19,30], Florisil [33], Strata X C, Strata X CW, Strata X AW, Sep Pak silica [30], Strata X [30,35], HySphere C18 HD, HySphere Resin GP, HySphere C8 HD [45], Sep Pak C18 [59], Isolute C18 and С 6 Н 5 [37], Varian C18 [34], and MP 1 [75]. For the selective separation of tetracycline anti biotics from food products, molecularly imprinted materials [68,73,74,77] and zeolite imidazolate [72]. Methanol [21,22,58,70,71,80,81] and the mixtures of ethyl acetate with methanol [34,37,79], acetoni trile with oxalic acid [29,33], and methanol with oxalic [15,19,58] and formic [69] acids are used as eluants.…”

“…Honey HPLC [34], [35], [37], [69], [73] FS [120] IC [36], [38], [135][136][137] CL [116] CL [116] FIA [33] FIA [33] VA [122], [123] FS [39] ISE [91], [121] Milk HPLC [55], [60], [71][72][73][74], [80], [81], [86], [138], [139] Blood and plasma CZE [75] CZE [56], [75], [76] CEC [128] IC [20], [135], [136] Various hydrophobic sorbents with grafted alkyl radicals, as a rule, C18, are used as stationary phases in reversed phase HPLC. Table 3 summarizes the exam ples of commercially available stationary phases used for the determination of tetracyclines in food prod ucts, feed, and environmental samples.…”

“…Photometric UV [23,51,53,60,73,74,80,81,89,113,124,134], diode array [15,19,22,29,37,55,68,72,84,86,138,139], and fluorescence [34,58,71,83,93,94] detectors are used for the detection of tetracy cline antibiotics. The number of works regarding the determination of tetracycline antibiotics by the HPLC with a mass spectrometric detector noticeably increased [15,21,27,32,35,69,100,105,106,112,114].…”