A novel surface molecularly imprinted polymer as the solid-phase extraction adsorbent for the selective determination of ampicillin sodium in milk and blood samples

Surface molecularly imprinted polymers （SMIPs） for selective adsorption of ampicillin sodium were synthesized using surface molecular imprinting technique with silica gel as a support. The physical and morphological characteristics of the polymers were investigated by scanning electron microscope （SEM）, Fourier transform infrared spectroscopy （FT-IR）, thermogravimetric analysis （TGA）, elemental analysis and nitrogen adsorption-desorption test. The obtained results showed that the SMIPs displayed great adsorption capacity （13.5 lag/mg）, high recognition ability （the imprinted factor is 3.2） and good binding kinetics for ampicillin sodium. Finally, as solid phase extraction adsorbents, the SMIPs coupled with HPLC method were validated and applied for the enrichment, purification and determination of anapicillin sodium in real milk and blood samples. The averages of spiked accuracy ranged from 92.1% to 107.6%. The relative standard deviations of intra- and inter-day precisions were less than 4.6%. This study provides a new and promising method for enriching, extracting and determining ampicillin sodium in complex biological samples.

A New Molecularly Imprinted Polymer for Solid-phase Extraction of Cotinine from Human Urine

A molecularly imprinted polymer （MIP）, prepared around a cotinine template, has been synthesized. The feasibility of using the polymer for solid-phase extraction （SPE） of cotinine from biological samples has been investigated. The results show that cotinine can be quantitatively retained and eluted from the polymer. Experiments with human urine samples indicate that clean target analyte is obtained for HPLC with UV detection using the protocol.

Molecularly Imprinted Polymers for Selective Extraction of Crystal Violet from Natural Seawater coupled with HighPerformance Liquid Chromatographic Determination

Molecularly imprinted polymers(MIPs) were prepared by the bulk polymerization using crystal violet as the template molecule, and the methacrylic acid and ethylene glycol dimetheacrylate as functional monomer and cross-linker, respectively. Systematic investigations of synthetic conditions were conducted. The surface morphology and recognition mechanism of the obtained polymers were studied using scanning electron microscope and spectrophotometric analysis. MIPs showed high affinity to template molecule and were successfully applied as special solid-phase extraction sorbent for selective extraction of crystal violet from natural seawater. An off-line molecularly imprinted solid-phase extraction(MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of crystal violet was also established. MISPE columns have good recoveries for crystal violet standard solutions and good linearity was obtained over the concentration range of 0-200 μg L-1(R2 > 0.99). Finally, two natural seawater samples were investigated. The recoveries of spiked seawater on the MISPE columns were from 44.47% to 62.34%, the relative standard deviation(n=3) being in the range of 2.89%-5.96%.

Preparation of Magnetic Molecularly Imprinted Polymers for Selective Isolation and Determination of Kaempferol and Protoapigenone in Macrothelypteris torresiana

Novel uniform-sized magnetic molecularly imprinted polymers （MMIPs） were synthe- sized for selective recognition of active antitumor ingredients of kaempferol （KMF） and protoapi- genone （PA） in Macrothelypteris torresiana （M. torresiana） by surface molecular imprinting tech- nique in this study. Super paramagnetic core-sheU nanoparticles （γ-MPS-SiO2@Fe3O4） were used as seeds, KMF as template molecule, acrylamide （AM） as functional monomer, and N, N＇-methylene bisacrylamide （BisAM） as cross-linker. The prepared MMIPs were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectrum fiT/R）, transmission electron microscopy （TEM） and thermo-gravimetric analysis （TGA）, respectively. The recognition capacity of MMIPs was 2.436 times of non-imprinted polymers. The adsorption results based on kinetics and isotherm analysis were in accordance with the pseudo-second-order model （R2=0.9980） and the Langmuir adsorption model （R2=0.9944）. The value of E （6.742 kJ/mol） calculated from the Dubinin-Radushkevich isotherm model suggested that the physical adsorption via hydrogen-bonding might be predominant. The Scatchard plot showed a single line （R2=0.9172） and demonstrated the homogeneous recognition sites on MMIPs for KMF. The magnetic solid phase extraction （MSPE） based on MMIPs as sorbent was established for fast and selective enrichment of KMF and its structural analogue PA from the crude extract of M. torresiana and then KMF and PA were detected by HPLC-UV. The established method showed good performance and satisfactory results for real sample analysis. It also showed the feasi- bility of MMIPs for selective recognition of active structural analogues from complex herbal extracts.

The Application of Molecularly Imprinted Polymers

Molecularly imprinted technology (MIT) has the characteristics of specificity and high selectivity, which is one of the most promising methodologies. Besides, the polymers are made using MIT as the functional material of solid-phase extraction and chromatographic fractionating and sensor, because of the characteristics of the high selectivity, the better stability and easy preparation. This review introduces the progress in the application of MIT and summarizes its application in the chemistry.

Selective Solid-phase Extraction of Aloe Emodin from Aloe by Molecularly Imprinted Polymers

The extraction and separation of aloe emodin were optimized via selective molecularly imprinted solid-phase extraction. Molecularly imprinted polymer was prepared from the functional monomer, methacrylic acid and a mixture of ethanol/dodecanol（90/10, volume ratio） as porogen. It overcomes the common problems of imprin- ting biological polar compounds and shows high selectivity compared favorably with those of non-imprinted polymer and commercially available C18 and silica cartridges in similar aloe emodin tests. Good linearity was obtained be- tween 0.002 and 2.5 mg/mL（r2=0.998） with relative standard deviations below 3.3%.

Molecularly Imprinted Polymer for Solid-Phase Extraction of Ecteinascidin 743 from Sea Squirt

Ecteinascidin 743 from sea squirt is one of the most original anti-tumoral activity compounds, as proven by the Natural Cancer Institute. Ecteinascidin 743 could be obtained with traditional liquid extraction, but it should be purified and separated from the extract. A molecularly imprinted solid-phase extraction procedure was developed for the selective separation. Ecteinascidin 743 was used as the template and the polymer was synthesized in a methanol environment. Water and n-hexane as the washing solvents can eliminate most of the interference. Good linearity and low relative standard deviations （less than 4.39%）justify its continuing development.

Determination of particulate polycyclic aromatic hydrocarbons in ambient air by gas chromatography-mass spectrometry after molecularly imprinted polymer extraction

A solid phase extraction procedure(SPE)is described for the quantitative analysis of polycyclic aromatic hydrocarbons(PAHs)in atmospheric particulate matter(PM),as ubiquitous environmental pollutants routinely measured in air qualitymonitoring.A SPE cartridge was used based on a molecular imprinted polymer(MIP-SPE)properly tailored for selective retention of PAHs with 4 and more benzene fused rings.The performance of the clean-up procedure was evaluated with the specific concern of selective purification towards saturated hydrocarbons,which are the PM components mostly interfering GC analysis of target PAHs.Under optimized operative conditions,the MIP-SPE provided analyte recovery close to 95%for heavier PAHs,from benzo(α)pyrene to benzo(ghi)perylene,and close to 90%for four benzene rings PAHs,with good reproducibility(RSDs:2.5%-5.9%).Otherwise,C_(17)-C_(32) n-alkanes were nearly completely removed.The proposed method was critically compared with Solid Phase Micro Extraction(SPME)using a polyacrylate fiber.Both methods were successfully applied to the analysis of ambient PM2.5 samples collected at an urban polluted site.Between the two procedures,the MIP-SPE provided the highest recovery(R%≥93%)for PAHs with 5 and more benzene rings,but lower for lighter PAHs.In contrast,SPME showed a mean acceptable R%value(∼80%)for all the investigated PAHs,except for the heaviest PAHs in the most polluted samples(R%:110%-138%),suggesting an incomplete purification from the interfering n-hydrocarbons.

Synthesis of curcuminoid-imprinted polymers applied to the solidphase extraction of curcuminoids from turmeric samples

A molecular imprinting polymer technique was successfully applied to precipitation polymerization by using styrene as a functional monomer, curcuminoids as templates, acetonitrile as a porogenic solvent,benzoyl peroxide as the initiator, and ethylene glycol dimethacrylate as the crosslinker. The effects of interaction on the adsorption capacity of the molecularly imprinted polymer(MIP) and non-imprinted polymer(NIP) were investigated. A comparison of the adsorption capacity for MIP and NIP indicated that the NIP had the lowest adsorption capacity. The curcuminoid-imprinted polymer(Cur-MIP) was synthesized from 0.0237 mmol of styrene, 47.0 g of acetonitrile, 1.0238 mmol of ethylene glycol dimethacrylate, 0.0325 mmol of curcuminoids, and 0.2480 mmol of benzoyl peroxide. A high-performance liquid chromatography method with fluorescence detection was developed and validated for various chromatographic conditions for the determination of the curcuminoids in turmeric samples. The sample solution was separated using the Cur-MIP via solid-phase extraction and analyzed on a Brownlee analytical C_(18) column(150 mm ×6 mm, 5 mm) using an isocratic elution consisting of acetonitrile and 0.1%trichloroacetic acid(40:60, v/v). The flow rate was maintained at 1.5 m L/min. The fluorescence detector was set to monitor at λex? 426 nm and λem? 539 nm. The quantification limit values were found to be16.66, 66.66, and 33.33 mg/L for curcumin, demethoxycurcumin, and bisdemethoxycurcumin, respectively. Thus, we concluded that the Cur-MIP and high-performance liquid chromatographic-fluorescence method could be applied to selective extraction and could be used as a rapid tool for the determination of curcuminoids in medicinal herbal extracts.

Molecularly Imprinted Micro-Solid-Phase Extraction for the Selective Determination of Phenolic Compounds in Environmental Water Samples with High Performance Liquid Chromatraphy

2,4,6-trichlorophenol molecularly imprinted suspension polymer has been prepared and applied to the molecularly imprinted micro-solid-phase extraction procedure for selective preconcentration of phenolic compounds from environmental water samples. The influence of functional monomer, cross-linker, polymerization condition, porogen, and the ratio of template molecule and functional monomer to cross-linker on the size of the obtained particles were investigated. It was found that methyacrylic acid as functional monomer, divinylbenzene as cross-linker, the molar ratio of template molecule and functional monomer to cross-linker was 1:4:20, the amount of AIBN was 100 mg, ultraviolet radiation at 365 nm were the optimal conditions, and at these conditions, the polymers had the best adsorption efficiency and had the monodispersity of 2 - 3 μm microsphere particles. The characteristics of the MIMSPE method were valid by high performance liquid chromatography. This MIMSPE-HPLC method has been successfully applied to the direct preconcentration and determination of phenolic compounds (phenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol) in environmental water samples.

Preparation and adsorption behaviors of Cu(Ⅱ) ion-imprinted polymers

Imprinted polymers were prepared for selective removal of Cu(II) ions from metal solutions. Three ion-imprinted polymers were synthesized with methacrylic acid (MAA), acrylamide (AA) and N,N'-methylenebisacrylamide (MBAA) respectively as the functional monomers, ethleneglycoldimethacrylate (EGDMA) as the cross-linking agent, 2,2'-azobisisobutyronitrile (AIBN) as the initiator and Cu (II) ion as the imprint ion. The template Cu (II) ion was removed from the polymer by leaching with a liquid of a 1:1 volumetric ratio of HCl to ethylenediaminetetraacetic acid (EDTA). The capacity and selectivity of Cu(II) ion adsorption were investigated with the three imprinted polymers and their non-imprinted counterparts. The polymers have a maximum adsorption capacity at pH 7.0. The isotherm of their batch adsorption of Cu(II) ions shows a Langmuir adsorption pattern. Imprinted polymers all have a much higher capacity and higher selectivity of Cu(II) adsorption than non-imprinted ones. MAA polymer benefits the most from imprinting. Imprinted MAA polymer has the highest selectivity when used to rebind Cu (II) ion from an aqueous solution in the presence of other metal ions. Ion imprinting can be a promising technique of preparing selective adsorbents to separate and preconcentrate metal in a medium of multiple competitive metal ions through solid phase extraction (SPE).

分子印迹固相萃取-高效液相色谱法测定果蔬中4种有机磷类农药的残留量

以4种目标物丙溴磷、毒死蜱、二嗪磷、辛硫磷的混合物作为模板分子,乙二醇二甲基丙烯酸酯为交联剂、甲基丙烯酸为功能单体,通过水热聚合法制备分子印迹聚合物(MIPs),将MIPs填充在聚丙烯空柱中制备MIPs固相萃取(MIPs-SPE)柱。将果蔬样品洗净、晾干、粉碎后,分取5.00 g,加入2 g无水硫酸钠,研磨均匀。加入30 mL乙腈,超声1.5 h,离心10 min。分取1 mL上清液过活化好的MIPs-SPE柱,用4 mL正己烷淋洗,6 mL体积比9∶1的甲醇-乙酸混合溶液洗脱。收集洗脱液,于35℃氮气吹干,用1 mL乙腈定容,用高效液相色谱法分析。结果显示:MIPs可特异性识别4种目标物,对目标物的吸附量约非分子印迹聚合物(NIPs)的2.5倍,对硫磷、马拉硫磷、甲拌磷、甲基毒死蜱的吸附量显著低于目标物的;经MIPs-SPE柱净化后,样品大部分基质成分被去除,目标物测定无干扰。4种目标物的浓度在0.005~2.0μmol·L^(−1)内和对应的峰面积呈线性关系,检出限(3S/N)为0.0015~0.0040μmol·L^(−1);在0.01,0.5,1.0,2.0 mg·kg^(−1)加标浓度水平下,4种目标物的回收率为85.9%~102%,测定值的相对标准偏差(n=5)为3.0%~7.1%。方法用于4种果蔬样品的分析,在草莓样品中检出了丙溴磷(检出量为0.07 mg·kg^(−1)),甘蓝样品中检出了辛硫磷(检出量为0.05 mg·kg^(−1)),其他样品中均未检出这4种目标物。

分子印迹技术在大环内酯类药物检测中的应用

分子印迹技术是模拟酶-底物、抗原-抗体之间的相互作用,对印迹分子进行专一识别的技术,能够特异性识别模板或类似物,常被用于分析样品的预处理,可对样品进行高效提取和净化。大环内酯类药物是畜牧业中常用抗生素之一,广泛用于畜禽呼吸道、胃肠道感染等疾病的预防与治疗,但不规范使用可能导致其在动物产品及环境中残留,对人类健康产生威胁。文章针对分子印迹技术对大环内酯类药物残留检测的预处理技术研究进展进行综述,重点对分子印迹固相萃取和磁性分子印迹固相萃取进行介绍,并对分子印迹技术在大环内酯类药物残留分析预处理的应用前景进行展望,为优化大环内酯类抗生素检测前处理方法提供参考。

用于复杂生物样品体系分离与识别的分子印迹技术最新进展

由生物样品中复杂组分所导致的基质效应会严重影响分离分析技术的准确性、灵敏度与可靠性。免疫亲和技术作为降低或消除基质效应的方法已被广泛应用于诊断分析和蛋白纯化等领域,但该技术仍存在明显的缺点,如成本高昂、制备流程繁琐、保存条件苛刻以及配体浸出等问题。目前,如何通过有效降低或消除复杂生物样品中的基质效应来实现痕量目标分析物的分离及识别仍是一个具有挑战性的问题。分子印迹技术(molecular imprinting technology,MIT)一直被广泛应用于固相萃取与色谱分离等领域,随着MIT的发展,各种新型印迹策略被提出;其中,分子印迹聚合物(molecularly imprinted polymer,MIP)作为一种能够模拟抗原-抗体间相互作用的高分子聚合物,可以从各种复杂生物样品中提取出目标分析物,从而有效消除基质效应的影响。MIP不仅拥有高特异性与高亲和力的优点,而且与抗体和适配体等生物大分子相比,MIP还具有稳定性高、成本低廉以及制备简便等优势。近年来一些基于MIT的传统分离技术得到了深入发展,其中包括色谱固定相以及固相萃取吸附剂等。此外,结合了MIT与高灵敏检测技术的分析方法在疾病诊断和生物成像等领域也受到了广泛关注。本文着重介绍了近年来发展的新型印迹策略,并介绍了基于MIP的分离分析方法在各领域中的应用以及现阶段存在的不足,最后对MIT的未来发展方向做出了展望。

分子印迹固相微萃取-超高效液相色谱串联质谱法检测肉牛体内三种苯二氮䓬类药物

以阿普唑仑、咪达唑仑、艾司唑仑为模板分子,苯基三甲氧基硅烷为功能单体,四乙氧基硅烷为交联剂,在乙醇-水体系中制备分子印迹聚合物,并在不锈钢丝上镀膜形成固相微萃取探针,结合超高效液相色谱串联质谱,快速检测生物检材中痕量苯二氮䓬类药物残留。3种苯二氮䓬类药物在0.1~100.0μg/L范围内线性关系良好,相关系数(R^(2))为0.994~0.997,检出限(S/N=3)为0.1~0.2μg/L。将开发的方法用于肉牛血液和尿液样本品中3种苯二氮䓬类药物的检测,加标回收率为80.9%~102.9%,重复6次试验的标准偏差<7.2%。结果表明,该方法前处理简单快速灵敏、检测准确度高,可用于活体动物中痕量苯二氮䓬类药物的快速检测。

分子印迹固相萃取-高效液相色谱法检测蔬菜中氧化乐果残留

通过水热聚合法制备氧化乐果分子印迹聚合物,模板分子为氧化乐果,交联剂为乙二醇二甲基丙烯酸酯、功能单体为甲基丙烯酸。将该氧化乐果分子印迹聚合物作为填料制备分子印迹固相萃取柱,优化固相萃取条件,建立了分子印迹固相萃取-高效液相色谱法测定蔬菜中氧化乐果的方法。在0.1×10^(-8)~2.0×10^(-6)mol·L^(-1)浓度范围内,氧化乐果线性关系良好,相关系数为0.9997,检出限为0.1×10^(-9)mol·L^(-1)(S/N=3)。不同添加水平(2.3×10^(-8)、2.3×10^(-7)、2.3×10^(-6)mol·kg^(-1)),加标回收率为86.9%~101.2%,相对标准偏差为3.61%~7.11%。结果表明:该方法操作简单、准确高效、特异性好、重现性高,适用于蔬菜中氧化乐果的测定。

Rapid, simple and selective determination of 2,4-dinitrophenol by molecularly imprinted spin column extraction coupled with fluorescence detection

A rapid, simple and selective method based on molecularly imprinted, spin column extraction coupled with fluorescence detection was successfully established for the determination of 2,4-dinitrophenol in serum samples. The 2,4-dinitrophenol imprinted polymers exhibited highly selective recognition for the template molecule and the maximum adsorption capacity was 138.9 mg/g. The results indicated that when water is used as the loading solution, only 2,4-dinitrophenol could be adsorbed on the spin column without the remaining structural analogs（2-nitrophenol, 4-nitrophenol and phenol）. After eluting with acetonitrile/acetic acid（9/1, v/v）, 2,4-dinitrophenol in serum samples could be determined by using the fluorescence spectrometer, based on the fluorescence enhancement of fluorescein by the template molecule. Under the optimal conditions, the spiked recovery ranged from 95.8% to 103.4% and the detection limit was 1 nmol/L. The results confirmed the reliability and practicality of the protocol and revealed a good perspective of this method for biological sample analysis.

适配体功能化分子印迹聚合物的研究进展

适配体在靶标的特异性识别和信号转换方面具有独特的技术优势,将适配体与分子印迹技术相结合,获得的适配体功能化分子印迹聚合物表现出优异的选择性识别能力和传感性能。基于此,介绍了适配体功能化分子印迹聚合物的制备方法,并对其在生物传感器以及分离与富集方面的应用进行了综述和展望(引用文献73篇)。

分子印迹固相萃取-液液微萃取-气相色谱法测定鱼样品中痕量环境激素

以题示方法测定鱼样品中痕量的双酚A(BPA)、苯胺(AN)、二苯胺(DPA)、4-氯-二甲基苯胺(CMAN)、3-氨基酚(3-AP)、苯酚(PH)等6种环境激素。以双酚A&苯胺双模板磁性分子印迹聚合物(D-MIP)为固相萃取剂,甲醇及乙酸混合溶液为洗脱剂,萃取鱼样品中6种环境激素;乙腈为分散剂,正辛醇为萃取剂,液液微萃取洗脱液,等体积甲醇稀释萃取液后进行气相色谱检测。结果表明,鱼样品经处理后基质干扰已消除,6种环境激素能有效分离。对固相萃取及液液微萃取进行了条件优化,优化结果为:洗脱剂甲醇与乙酸用量为3 mL(V甲醇∶V乙酸=8∶2),洗脱时间2 min,D-MIP用量30 mg,固相萃取时间10 min,鱼样品溶液体积50 mL;液液微萃取剂为正辛醇,正辛醇用量90μL,乙腈为分散剂,乙腈用量0.5m L,5 mL10%NaCl溶液,pH=7。在优化的条件下,6种环境激素的标准曲线的线性范围为0.1~50μg/L,检出限(3S/N)为0.1~0.5 ng/L;对空白鲫鱼肉样品进行2个浓度水平的加标回收试验,6种环境激素的回收率为86.1%~92.5%,测定值的相对标准偏差(n=3)均小于1.8%;方法用于6种鱼样品的分析,只有鲫鱼鳃含有BPA 0.1μg/kg,其他均未检出。此方法将为鱼类中环境激素的含量检测提供方法依据。

虚拟模板表面分子印迹聚合物固相萃取噻虫嗪

采用共价有机骨架MCTP-1为载体材料,6-苄氨基嘌呤为虚拟模板,采用沉淀聚合的方法合成噻虫嗪表面分子印迹聚合物(MCTP-1@MIPs)。利用红外光谱、扫描电镜和X-射线衍射对所合成的聚合物进行表征。吸附测试表明,在0.5~30μg/mL测定范围内最大吸附量可达8.81μg/mg,且10 min即可达吸附-解析平衡,聚合物对噻虫嗪的印迹因子为2.04,对于噻虫嗪具有高选择性。将聚合物作为柱填料,制备成固相萃取柱,优化固相萃取柱使用条件,使用高效液相色谱-二极管阵列检测器进行检测,建立一种灵敏可靠的检测噻虫嗪的方法。为水中噻虫嗪残留的分离富集检测提供了新思路。