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 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.

Synthesis and Solid Phase Extraction Performance Study of NNAL-specific Molecularly Imprinted Polymers Using Dummy Templates

Dummy molecularly imprinted polymers （DMIPs） for 4-（methylnitrosamino）-1-（3-pyridyl）-1-butanol （NNAL） were produced using three structural analogues as dummy template molecules. The chosen analogues were 4-（acetymethylamino）-1-（3-pyridyl）-butanol, 4- （methylamino）-1-（3-pyridyl）-1-butanol, and 1-（3-pyridyl）-1,4,-butanediol. The molecular recognition characteristics of the produced polymers were evaluated by X-ray photoelec- tron spectroscopy （XPS） and Fourier transform infrared spectroscopy （FT-IR）. Interactions between NNAL and methacrylic acid should be cooperative hydrogen bonds while the ni- trogen atom of the pyridine ring and the oxygen atom of the nitroso group in NNAL are two of the hydrogen-bond acceptors. It was further demonstrated that DMIP synthesized by 4-（acetymethylamino）-1-（3-pyridyl）-butanol had the best binding performance by XPS and FT-IR. Then dummy molecularly imprinted solid phase extraction （DMISPE） was developed for the determination of the analyte using the hit polymer as the sorbing material. Under optimal conditions, the recovery of NNAL dissolved in standard solution reached 93%. And the investigated polymer exhibited much higher binding of NNAL when nicotine was acted as the competitive molecule. Also the proposed method was applied to the measurement of NNAL spiked in blank urine samples with recoveries ranging from 87.2% to 101.2%.

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.

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.

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.

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%.

MISPE-HPLC检测水产品5种丁香酚麻醉剂的残留量

釆用分子印迹固相萃取结合高效液相色谱法,建立检测水产品中5种丁香酚类麻醉剂残留的方法。分别使用丁香酚、甲基丙烯酸、乙二醇二甲基丙烯酸酯作为模板分子、功能单体和交联剂,采用本体聚合法制备合成分子印迹聚合物并制成萃取柱。通过响应面分析法得出模板分子、功能单体、交联剂的最佳比例14.5523.21;样品溶剂选择甲醇能使5种丁香酚类化合物回收率达到90%;洗脱剂选择91的甲醇乙酸溶液能够使5种丁香酚类化合物回收率达90%以上;该方法的线性范围均为0.05-10μg/mL,相关系数为0.999 83-0.999 97,具有较好的线性关系;5种丁香酚类麻醉剂的定量限为0.05 mg/kg。该方法对样品的回收率为82.04%-99.29%,RSD为0.06%-3.96%。所建立的方法具有简单便于操作、准确快速、操作可行性高、有机溶剂耗量少等特点,可用于水产品中5种丁香酚类麻醉剂残留的测定。

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。

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.

虚拟模板MIPs-SPE联用技术对茶叶粗提物中咖啡因的分离纯化研究

目的 采用儿茶素作为虚拟模板制备分子印迹聚合物(Molecular imprintingpolymers,MIPs)结合固相萃取(Solid phase extraction,SPE)技术对茶叶粗提物中的咖啡因进行分离纯化。方法 以儿茶素为虚拟模板,4-乙烯基吡啶为功能单体,乙二醇二甲基丙烯酸酯为交联剂,聚苯乙烯为大分子拥挤试剂,以原位聚合的方式制备虚拟模板分子印迹聚合物。测定该分子印迹聚合物的保留性能、形貌特征和孔径分布等性能,以该分子印迹聚合物作为固相萃取吸附剂,对茶叶粗提物中的咖啡因进行分离纯化。结果 所制备儿茶素分子印迹聚合物对咖啡因的最优印迹因子为4.57。对茶叶粗提物中的咖啡因进行分离纯化后,在咖啡因纯度高于95%的条件下,咖啡因的回收率可达85%以上。结论 以儿茶素为虚拟模板合成的分子印迹聚合物,可以用于茶叶粗提物中咖啡因的分离纯化。

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。

分子印迹固相萃取-同位素稀释气相色谱质谱法测定肉制品中16种欧盟优控多环芳烃

结合分子印迹固相萃取对多环芳烃的特异性净化,建立了同位素稀释气相色谱质谱法测定肉制品中16种欧盟优控多环芳烃的分析方法.样品加入7种氘代同位素内标,经正己烷+二氯甲烷(7:3,V/V)混合溶液提取,分子印迹固相萃取柱净化,选择离子监测模式(SIM)下采集.在1.0—200 ng·mL^(−1)范围内,16种欧盟优控多环芳烃线性相关系数(r)均大于0.9990,不同加标浓度下,回收率为87.1%—114.8%,相对标准偏差(RSDs)(n=6)在1.0%—5.5%范围内,方法的检出限为0.2—0.3μg·kg^(−1),定量限为0.6—0.9μg·kg^(−1).方法前处理简单高效,灵敏度高,适用大批量肉制品中多环芳烃的快速测定.

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。

Molecularly imprinted polymers as the extracted sorbents of clenbuterol ahead of liquid chromatographic determination

A pre-treatment methodology for clenbuterol hydrochloride （CLEN） isolation and enrichment in a complex matrix environment was developed through exploiting molecularly imprinted polymers （MIPs）. CLEN-imprinted pol- ymers were synthesized by the combined use of ally-β-cyclodextrin （ally-13-CD） and methacrylic acid （MAA）, allyl-β-CD and acrylonitrile （AN）, and allyl-β-CD and methyl methacrylate （MMA） as the binary functional monomers. MAA-linked allyl-β-CD MIPs （M-MAA） were characterized by Fourier transform-infrared （FT-IR） spectroscopy and a scanning electron microscope （SEM）. Based upon the results, M-MAA polymers generally proved to be an excellent selective extraction compared to its references： AN-linked allyl-β-CD MIPs （M-AN） and MMA-linked allyl-β-CD MIPs （M-MMA）. M-MAA polymers were eventually chosen to run through a molecularly imprinted solid-phase extraction （MISPE） micro-column to enrich CLEN residues spiked in pig livers. A high recovery was achieved, ranging from 91.03% to 96.76% with relative standard deviation （RSD） ≤4.45%.

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。

Development of new solid phase extraction techniques in the last ten years

Solid phase extraction （SPE） is a widely used sample pretreatment method for separation, purification and enrichment, which has been established due to its significant advantages of time-saving, low consumption of solvent, high enrichment factor, high accuracy, etc. In recent years, a variety of new SPE methods such as molecularly imprinted solid phase extraction （MISPE）, magnetic solid phase extraction （MSPE）, solid phase micro-extraction （SPME）, etc., which are superior to the conventional SPE, have been developed and been widely applied to food, drugs, and environmental monitoring. In this paper, the basic principles and methods of SPE and its new applications in different areas are reviewed.