Preconcentration of indapamide from human urine using molecularly imprinted solid‐phase extraction

A simple, sensitive, and selective molecularly imprinted solid‐phase extraction and spectrophotometric method has been developed for the clean‐up and preconcentration of indapamide from human urine. Molecularly imprinted polymers were prepared by a non‐covalent imprinting approach using indapamide as a template molecule, 2‐(trifluoromethyl) acrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, N,N‐azobisisobutyronitrile as a thermal initiator and acetonitrile as a porogenic solvent. A non‐imprinted polymer was also prepared in the same way, but in the absence of template. Molecularly imprinted polymer and non‐imprinted polymer sorbents were dry‐packed into solid‐phase extraction cartridges. Eluates from cartridges were analyzed using a spectrophotometer for the determination of indapamide by referring to the calibration curve in the range 0.14–1.50 μg/mL. Preconcentration factor, limit of detection, and limit of quantification were 16.30, 0.025 μg/mL, and 0.075 μg/mL, respectively. A relatively high imprinting factor (9.3) was also achieved and recovery values for the indapamide spiked into human urine were in the range of 80.1–81.2%. In addition, relatively low within‐day (0.17–0.42%) and between‐day (1.1–1.4%) precision values were obtained as well. The proposed molecularly imprinted solid‐phase extraction and spectrophotometric method was successfully applied to selective extraction, preconcentration, and determination of indapamide from human urine samples.     

Development of a molecularly imprinted polymer for selective extraction followed by liquid chromatographic determination of sitagliptin in rat plasma and urine

A novel water-compatible molecularly imprinted solid-phase extraction (MISPE) combined with zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC) method for selective extraction and determination of sitagliptin in rat serum and urine was developed and validated. The effects of progenic solvents, pH, cross linker and amount of monomer were studied to optimize the efficiency and selectivity. The adsorption kinetics and isotherms were measured. The molecularly imprinted polymer (MIP) showed good specific adsorption capacity with an optimum of 180 mg/g at pH 7.5 and selective extraction of sitagliptin from rat plasma and urine. The recovery of sitagliptin from rat urine and plasma was >98%. The limits of detection (LOD) and quantification (LOQ) were 0.03 and 0.10 μg/L respectively. The proposed method overcomes the matrix effects of phospholipids generally encountered while preparation of plasma samples by precipitation of proteins.     

Efficient strategy for the selective determination of dopamine in human urine by molecularly imprinted solid‐phase extraction

An efficient molecularly imprinted solid‐phase extraction protocol was developed for the separation of dopamine (DA) from human urine. After successful validation of the analytical method using high‐performance liquid chromatography coupled with fluorescence detection, a new strategy for the selective determination of DA in the presence of norepinephrine and epinephrine in human urine was presented. In the proposed protocol, the LODs and quantification for DA were 166 ± 36 and 500 ± 110 nmol/L, respectively, and the total recoveries of DA in the range of 1–15 μmol/L varied between 98.3 and 101.1%. DA was detected in the real urine samples at the level of 47–167 μg/L (0.250–0.895 μmol/L). The superiority of the novel analytical strategy was shown by comparison with the results obtained for a commercially available imprinted sorbent.     

Preparation and utilization of a molecularly imprinted polymer for solid phase extraction of tramadol

In this paper, a highly selective molecularly imprinted polymer (MIP) for tramadol hydrochloride, a drug used to treat moderate to severe pain, was prepared and its use as solid-phase extraction (SPE) sorbent was demonstrated. The molecularly imprinted solid-phase extraction procedure followed by high performance liquid chromatography with ultraviolet detector (MISPE-HPLC) was developed for selective extraction and determination of tramadol in human plasma and urine. The optimal conditions for molecularly imprinted solid-phase extraction (MISPE) consisted of conditioning with 1 mL methanol and 1 mL of deionized water at neutral pH, loading of tramadol sample (50 μg L⁻¹) at pH 7.5, washing using 1 mL acetone and elution with 3 × 1 mL of 10% (v/v) acetic acid in methanol. The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of tramadol. Results from the HPLC analyses showed that the calibration curve of tramadol (using MIP from human plasma and urine) is linear in the ranges of 6–100 and 3–120 μg L⁻¹ with good precisions (1.9% and 2.9% for 5.0 μg L⁻¹), respectively. The recoveries for plasma and urine samples were higher than 81%.      

Water‐compatible molecularly imprinted polymer as a sorbent for the selective extraction and purification of adefovir from human serum and urine

A molecularly imprinted polymer has been synthesized to specifically extract adefovir, an antiviral drug, from serum and urine by dispersive solid‐phase extraction before high‐performance liquid chromatography with UV analysis. The imprinted polymers were prepared by bulk polymerization by a noncovalent imprinting method that involved the use of adefovir (template molecule) and functional monomer (methacrylic acid) complex prior to polymerization, ethylene glycol dimethacrylate as cross‐linker, and chloroform as porogen. Molecular recognition properties, binding capacity, and selectivity of the molecularly imprinted polymers were evaluated and the results show that the obtained polymers have high specific retention and enrichment for adefovir in aqueous medium. The new imprinted polymer was utilized as a molecular sorbent for the separation of adefovir from human serum and urine. The serum and urine extraction of adefovir by the molecularly imprinted polymer followed by high‐performance liquid chromatography showed a linear calibration curve in the range of 20–100 μg/L with excellent precisions (2.5 and 2.8% for 50 μg/L), respectively. The limit of detection and limit of quantization were determined in serum (7.62 and 15.1 μg/L), and urine (5.45 and 16 μg/L). The recoveries for serum and urine samples were found to be 88.2–93.5 and 84.3–90.2%, respectively.     

安定分子印迹聚合物的制备及应用

以安定为模板分子,通过本体聚合和沉淀聚合的方法合成了分子印迹聚合物材料,考察了交联剂、致孔剂及温度等条件对聚合物材料性能的影响。电镜扫描图片显示本体聚合得到的聚合物呈不规则形状,而沉淀聚合得到的则是微球颗粒,形状规则。吸附实验表明,聚合物微球对安定的最大吸附量约为130μg/g,对奥沙西泮和硝西泮的吸附量约为110μg/g,对安定类化合物具有较高的吸附性能和选择性。通过对比合成现象和聚合物性能,最终选用以DVB为交联剂、乙腈为致孔剂合成的聚合物微球为固相萃取材料填充固相萃取小柱,从饲料及猪尿样品中选择性地分离、富集痕量安定类药物。结合高效液相色谱法检测,奥沙西泮、硝西泮和安定3种药物在0.1～20 mg/L范围内线性良好,相关系数为0.999 6～0.999 9,检出限(S/N=3)为0.03～0.08 mg/L,加标回收率为66%～79%。该方法为安定类药物的检测提供了一种新途径。     

Development of a molecularly imprinted solid‐phase extraction sorbent for the selective extraction of telmisartan from human urine

A novel molecularly imprinted solid‐phase extraction with spectrofluorimetry method has been developed for the selective extraction of telmisartan from human urine. Molecularly imprinted polymers were prepared by a noncovalent imprinting approach through UV‐radical polymerization using telmisartan as a template molecule, 2‐dimethylamino ethyl methacrylate as a functional monomer, ethylene glycol dimethacrylate as a cross‐linker, N,N‐azobisisobutyronitrile as an initiator, chloroform as a porogen. Molecularly imprinted polymers and nonimprinted control polymer sorbents were dry‐packed into solid‐phase extraction cartridges, and eluates from cartridges were analyzed using a spectrofluorimeter. Limit of detection and limit of quantitation values were 11.0 and 36.0 ng/mL, respectively. A very high imprinting factor (16.1) was achieved and recovery values for the telmisartan spiked in human urine were in the range of 76.1–79.1%. In addition, relatively low within‐day (0.14–1.6%) and between‐day (0.11–1.31%) precision values were obtained. Valsartan was used to evaluate the selectivity of sorbent as well. As a result, a sensitive, selective, and simple molecularly imprinted solid‐phase extraction with spectrofluorimetry method has been developed and successfully applied to the direct determination telmisartan in human urine.     

Determination of sulfadiazine in eggs using molecularly imprinted solid‐phase extraction coupled with high‐performance liquid chromatography

The development of a simple and effective method for the isolation and purification of sulfadiazine residues in food of animal origin is of great significance since it is a great danger to human health. An off‐line molecularly imprinted solid‐phase extraction with high‐performance liquid chromatography method was proposed for the selective pretreatment and determination of sulfadiazine in eggs, rapidly and effectively. The molecularly imprinted polymer was proved to have a homogeneous spherical structure and porous surface morphology with excellent adsorption capacity of 5258 μg/g for sulfadiazine. The newly established method showed a good linearity in the range of 0–200 μg/L, low limits of detection (0.06 μg/L), acceptable reproducibility (RSD, 2.60–5.03%, n = 3), and satisfactory relative recoveries (78.22–86.10%). It was demonstrated that the proposed molecularly imprinted solid‐phase extraction with high‐performance liquid chromatography method could be applied to determine sulfadiazine in eggs, which simplified the pretreatment procedure and improved the accuracy of the analysis process by reducing the loss of sulfadiazine in the fat‐removing procedure compared with traditional methods. Molecularly imprinted solid‐phase extraction with excellent selectivity and adsorption capacity is a simple, rapid, selective, and effective pretreatment method for the determination of sulfadiazine in egg samples.     

Molecularly imprinted solid-phase extraction for the selective determination of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs in human whole blood by gas chromatography-mass spectrometry

A novel method is described for the extraction of methamphetamine, amphetamine, and methylenedioxyphenylalkylamine designer drugs, such as 3,4-methylenedioxy-methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxyethylamphetamine, N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine, and 3,4-(methylenedioxyphenyl)-2-butanamine, from human whole blood using molecularly imprinted solid-phase extraction as highly selective sample clean-up technique. Whole blood samples were diluted with 10 mmol/L ammonium acetate (pH 8.6) and applied to a SupelMIP-Amphetamine molecularly imprinted solid-phase extraction cartridge. The cartridge was then washed to eliminate interferences, and the amphetamines of interest were eluted with formic acid/methanol (1:100, v/v). After derivatization with trifluoroacetic anhydride, the analytes were quantified using gas chromatography-mass spectrometry. Recoveries of the seven amphetamines spiked into whole blood were 89.1-102%. The limits of quantification for each compound in 200 μL of whole blood were between 0.25 and 1.0 ng. The maximum intra- and inter-day coefficients of variation were 9.96 and 13.8%, respectively. The results show that methamphetamine, amphetamine, and methylenedioxyphenylalkyl-amine designer drugs can be efficiently extracted from crude biological samples such as whole blood by molecularly imprinted solid-phase extraction with good reproducibility. This extraction method will be useful for the pretreatment of human samples before gas chromatography-mass spectrometry.     

Synthesis of molecularly imprinted polymer adsorbents for solid‐phase extraction of strobilurin fungicides from agricultural products

Molecularly imprinted polymers for strobilurin fungicides were prepared by precipitation polymerization employing azoxystrobin as template molecular together with methacrylic acid monomer and trimethylolpropane triacrylate cross‐linker. Morphological characterization showed molecularly imprinted polymers were uniform spherical particles with about 0.2 μm in diameter, while the morphologies of nonimprinted polymers were irregular bulk. The equilibrium binding and selective experiments proved that molecularly imprinted polymers possessed a higher affinity toward four fungicides compared to nonimprinted polymers and heterogeneous binding sites were found in the molecularly imprinted polymers. Molecularly imprinted solid‐phase extraction conditions, including sample loading solvents, selective washing, and elution solvents, were carefully optimized. The developed method showed good recoveries (70.0–114.0%) with relative standard deviations in range of 1.0–9.8% (n  =  3) for samples (cucumber and peach) spiked at three different levels (10, 50, and 100 μg/ kg). The detection limit (signal/noise = 3) ranged from 0.01 to 0.08 μg/kg. The results demonstrated good potential use of this convenient and highly efficient method for determining trace strobilurin fungicides in agricultural products.     

Determination of ofloxacin and lomefloxacin in chicken muscle using molecularly imprinted solid-phase extraction coupled with liquid chromatography

A new molecularly imprinted solid-phase extraction (MISPE) procedure combined with liquid chromatography was developed for the simultaneous selective extraction and determination of ofloxacin (OFL) and lomefloxacin (LOM) in chicken muscle samples. The water-compatible molecularly imprinted microspheres (MIMs) were synthesized by aqueous suspension polymerization using 2-hydroxy-3-naphthoic acid and 1-methylpiperazine as mimic templates. The MIMs applied as selective sorbents in SPE method showed high selectivity and affinity to OFL and LOM in complex biological matrices. Good linearity was obtained in a range of 0.025-2.0 μg/g, and the average recoveries of OFL and LOM at three spiked levels ranged from 94.4 to 96.9%, respectively, with the relative standard deviation ≤4.7%. The developed MISPE-HPLC method was successfully applied to the isolation of OFL and LOM in chicken muscles, which demonstrated the potential ability of the novel MIMs for selective extraction of fluoroquinolones in biological samples.     

Selective and sensitive determination of protoberberines by capillary electrophoresis coupled with molecularly imprinted microextraction

In this work, we developed a novel molecularly imprinted solid‐phase microextraction with capillary electrophoresis method for the selective extraction and determination of protoberberines in complicated samples. The imprinted monolith was prepared in a micropipette tip‐based device by using acrylamide as the functional monomer, ethyleneglyoldimethacrylate as the cross‐linker and dimethylsulfoxide as the porogen, and exhibited an imprinting factor of 2.41 to berberine, 2.36 to palmatine and 2.38 to jatrorrhizine. Good capillary electrophoresis separation was achieved by using 20 mM phosphate buffer at pH 7 as running buffer with the addition of organic modifier of 10% methanol. Parameters such as sample pH value, sample flow rate and sample volume were investigated for imprinted monolith‐based solid‐phase microextraction. An imprinted solid‐phase microextraction with capillary electrophoresis method was developed, the method showed a wide linear range (0.3–50 μg/mL), good linearity (R² ≥ 0.9947) and good reproducibility (relative standard deviations ≤ 0.73%), the limit of detection was as low as 0.1 μg/mL, which was lower than some reported methods based on capillary electrophoresis for protoberberines. The method has been applied for determination of three common protoberberines in Cortex Phellodendri Chinensis, by using a molecularly imprinted monolith as the selective sorbent, most of the matrices in the Cortex Phellodendri Chinensis sample were removed and three protoberberines were selectively enriched and well determined.     

Determination of pharmaceuticals in wastewaters using solid-phase extraction-liquid chromatography-tandem mass spectrometry

Four different commercial sorbents for solid-phase extraction have been evaluated for the extraction of a group of acidic pharmaceuticals in terms of selectivity and capacity: Oasis hydrophilic-lipophilic balance (HLB), Oasis MAX (strong anion exchange), Oasis WAX (weak anion exchange) and a commercial available molecularly imprinted polymer specific for non-steroidal anti-inflammatory drugs. Among the sorbents studied, molecularly imprinted polymer proved to be very effective in the reduction of matrix interferences and the selective extraction of acidic pharmaceuticals, such as salicylic acid, ibuprofen, fenoprofen, diclofenac and naproxen, among others, from effluent wastewater samples. Moreover, molecularly imprinted solid-phase extraction protocol was applied to liquid chromatography coupled to tandem mass spectrometry (MS/MS) with the purpose of evaluating the clean-up effect on ion suppression/enhancement when the complexity of the samples increases and a reduction of this effect was observed. Molecularly imprinted solid-phase extraction followed by liquid chromatography coupled to ultraviolet detection and liquid chromatography coupled to tandem mass spectrometry validation methodologies with effluent wastewaters were developed, obtaining recoveries between 70 and 85% and limits of detection at low levels of μg/L (0.15-1 μg/L) and ng/L (0.5-2 ng/L), respectively. The final application of molecularly imprinted solid-phase extraction and liquid chromatography coupled to MS/MS detection showed the presence of acidic pharmaceuticals studied in this work in effluent wastewaters (相似文献   

Pharmacokinetic study and the extraction efficiency of bulk and precipitated ibuprofen-imprinted polymer sorbents for gas chromatography and gas chromatography-mass spectrometry ibuprofen bio-analysis

Bulk and precipitation polymerization methods were used to prepare ibuprofen-molecularly imprinted polymers. Molecularly imprinted polymer-bulk and -precipitation were synthesized in acetonitrile, likewise molecularly imprinted polymer-bulk (mixture) and molecularly imprinted polymer-precipitation (mixture) in a mixture of acetonitrile/toluene (75:25 v/v). N₂ adsorption-desorption analysis data revealed that molecularly imprinted polymer-precipitation (mixture) has the highest specific surface area (200.74 m²/g). The surface chemistry and morphology of the synthesized sorbents were investigated by Fourier-transform infrared analysis and scanning electron microscope micrographs respectively. The prepared sorbents in the mixture of solvents were used in a dispersive solid-phase extraction process for selective extraction and pre-concentration of ibuprofen from urine and human plasma samples. The detection limits were 62.91 and 7.89 ng/ml using molecularly imprinted polymer-bulk (mixture) and molecularly imprinted polymer-precipitation (mixture), respectively. Also, the sorbents showed selective behavior to extract ibuprofen in the presence of naproxen, fenoprofen, and ketoprofen. Overall, the results showed that the precipitation method in the mixture of acetonitrile/toluene resulted in the preparation of a sorbent with the highest extraction efficiency. Furthermore, a pharmacokinetic study was done. The maximum plasma concentration, the time required for maximum plasma concentration, and plasma half-life were 28.95 μg/ml, 2, and 2.39 h, respectively.     

Preparation and selective recognition of a novel solid‐phase microextraction fiber combined with molecularly imprinted polymers for the extraction of parabens in soy sample

A prepared molecularly imprinted polymer with ethyl p‐hydroxybenzoate as template molecule was applied for the first time to a homemade solid‐phase microextraction fiber. The molecularly imprinted polymer‐coated solid‐phase microextraction fiber was characterized by scanning electron microscopy and thermogravimetric analysis. Various parameters were investigated, including extraction temperature, extraction time, and desorption time. Under the optimum extraction conditions, the molecularly imprinted polymer‐coated solid‐phase microextraction fiber exhibited higher selectivity with greater extraction capacity toward parabens compared with the nonimprinted polymer‐coated solid‐phase microextraction fiber and commercial fibers. The molecularly imprinted polymer‐coated solid‐phase microextraction fiber was tested using gas chromatography to determine parabens, including methyl p‐hydroxybenzoate, ethyl p‐hydroxybenzoate, and propyl p‐hydroxybenzoate. The linear ranges were 0.01–10 μg/mL with a correlation coefficient above 0.9943. The detection limits (under signal‐to‐noise ratio of 3) were below 0.30 μg/L. The fiber was successfully applied to the simultaneous analysis of three parabens in spiked soy samples with satisfactory recoveries of 95.48, 97.86, and 92.17%, respectively. The relative standard deviations (n=6) were within 2.83–3.91%. The proposed molecularly imprinted polymer‐coated solid‐phase microextraction method is suitable for selective extraction and determination of trace parabens in food samples.     

Selective solid‐phase extraction using a molecularly imprinted polymer for the analysis of patulin in apple‐based foods

The aim of this work was to evaluate the use of a molecularly imprinted polymer as a selective solid‐phase extraction sorbent for the clean‐up and pre‐concentration of patulin from apple‐based food products. Ultra high pressure liquid chromatography coupled to ultraviolet absorbance detection was used for the analysis of patulin. The molecularly imprinted polymer was applied, for the first time, to the determination of patulin in apple juice, puree and jam samples spiked within the maximum levels specified by the European Commission No. 1881/2006. High recoveries (>77%) were obtained. The method was validated and found to be linear in the range 2–100 μg/kg with correlation coefficients greater than 0.965 and repeatability relative standard deviation below 11% in all cases. Compared with dispersive solid‐phase extraction (QuEChERS method) and octadecyl sorbent, the molecularly imprinted polymer showed higher recoveries and selectivity for patulin. The application of Affinisep molecularly imprinted polymer as a selective sorbent material for detection of patulin fulfilled the method performance criteria required by the Commission Regulation No. 401/2006, demonstrating the suitability of the technique for the control of patulin at low ppb levels in different apple‐based foods such as juice, puree and jam samples.     

Magnetic molecularly imprinted composite for the selective solid‐phase extraction of p‐aminosalicylic acid followed by high‐performance liquid chromatography with ultraviolet detection

A new method for the selective extraction of p‐aminosalicylic acid from aqueous and urine samples has been developed using magnetic molecularly imprinted polymer nanoparticles before determination by high‐performance liquid chromatography. The Fe₃O₄ nanoparticles were first prepared through the chemical coprecipitation of Fe²⁺ and Fe³⁺ and then coated with a vinyl shell. Subsequently, a layer of molecularly imprinted polymers was grafted onto the vinyl‐modified magnetic nanoparticles by precipitation polymerization. FTIR spectroscopy, scanning electron microscopy, vibrating sample magnetometry, and thermogravimetric analysis were applied to characterize the sorbent properties. Moreover, the predominant parameters affecting the magnetic solid phase extraction such as sample pH, sorption and elution times, the amount of sorbent, and composition and volume of eluent were investigated thoroughly. The maximum sorption capacity of the imprinted polymer toward p‐aminosalicylic acid was 70.9 mg/g, which is 4.5 times higher than that of the magnetic nonimprinted polymer. The magnetic molecularly imprinted polymer nanoparticles were applied for the selective extraction of p‐aminosalicylic acid from aqueous and urine samples and satisfactory results were achieved. The results illustrate that magnetic molecularly imprinted polymer nanoparticles have a great potential in the extraction of p‐aminosalicylic acid from environmental and biological matrices.     

Determination of Acrolein‐Derived 3‐Hydroxypropylmercapturic Acid in Human Urine Using Solid‐phase Extraction Combined with Molecularly Imprinted Mesoporous Silica and LC‐MS/MS Detection

A novel method for the analysis of (3‐hydroxypropyl)mercapturic acid (HPMA), a major acrolein metabolite in human urine incorporating a molecularly imprinted solid‐phase extraction (MISPE) process using N‐acetylcysteine ‐imprinted mesoporous silica particles coupled with LC‐MS/MS detection was developed. The molecularly imprinted mesoporous silica particles were synthesized based on the supported material of ordered mesoporous silica SBA‐15 with N‐acetylcysteine (NAC) as template using surface molecular imprinting technology. The condition of MISPE procedures was optimized. The use of MISPE improved the accuracy and precision of the LC‐MS method and lowered the limit of detection (0.23 ng/mL). The recoveries at three spiked levels ranged between 88.5% to 108.6%. The developed MISPE method enabled the selective extraction of HPMA successfully in human urine and could be used as an effective approach for the determination of ultra‐trace HPMA in complex biological matrices. The results in real samples showed that median levels of HPMA were significantly higher (1922.0 ng/mg of creatinine, N = 75) in smokers than in nonsmokers (759.1 ng/mg of creatinine, N = 5), demonstrating the higher acrolein uptake in smokers than in nonsmokers.     

Novel adsorptive materials by adenosine 5ʹ‐triphosphate imprinted‐polymer over the surface of polystyrene nanospheres for selective separation of adenosine 5ʹ‐triphosphate biomarker from urine

In this study, we have developed a method to assess adenosine 5?‐triphosphate by adsorptive extraction using surface adenosine 5′‐triphosphate‐imprinted polymer over polystyrene nanoparticles (412 ± 16 nm) for selective recognition/separation from urine. Molecularly imprinted polymer was synthesized by emulsion copolymerization reaction using adenosine 5′‐triphosphate as a template, functional monomers (methacrylic acid, N‐isopropyl acrylamide, and dimethylamino ethylmethacrylate) and a crosslinker, methylenebisacrylamide. The binding capacities of imprinted and non‐imprinted polymers were measured using high‐performance liquid chromatography with UV detection with a detection limit of 1.6 ± 0.02 µM of adenosine 5′‐triphosphate in the urine. High binding affinity (Q_MIP, 42.65 µmol/g), and high selectivity and specificity to adenosine 5′‐triphosphate compared to other competitive nucleotides including adenosine 5?‐diphosphate, adenosine 5?‐monophosphate, and analogs such as adenosine, adenine, uridine, uric acid, and creatinine were observed. The imprinting efficiency of imprinted polymer is 2.11 for urine (Q_MIP, 100.3 µmol/g) and 2.51 for synthetic urine (Q_MIP, 48.5 µmol/g). The extraction protocol was successfully applied to the direct extraction of adenosine 5′‐triphosphate from spiked human urine indicating that this synthesized molecularly imprinted polymer allowed adenosine 5′‐triphosphate to be preconcentrated while simultaneously interfering compounds were removed from the matrix. These submicron imprinted polymers over nano polystyrene spheres have a potential in the pharmaceutical industries and clinical analysis applications.     

Application of a magnetic molecularly imprinted polymer for the selective extraction and trace detection of lamotrigine in urine and plasma samples

Magnetic molecularly imprinted polymers have been synthesized for the selective preconcentration and trace determination of lamotrigine (LTG) in urine and plasma samples. The magnetic nanoparticles were modified by tetraethyl orthosilicate and 3‐methacryloxypropyl trimethoxysilane before imprinting. The magnetic molecularly imprinted polymers were prepared via surface molecular imprinting technique, using Fe₃O₄ as a magnetic component, LTG as template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross‐linker, and 2,2′‐azobisisobutyronitrile as a radical initiator in methanol/acetonitrile (50:50, v/v) as the porogen. The obtained sorbent was characterized using scanning electron microscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction, and thermal analysis. Separation of the sorbent from the sample solution was simply achieved by applying an external magnetic field. Determination of the extracted drug was performed by high‐performance liquid chromatography with UV detection. Under the optimum extraction conditions, the method detection limits were 0.7 μg/L (based on S/N of 3) for urine samples and 0.5 μg/L for plasma samples. A linear dynamic range of 1–1000 μg/L was obtained for LTF in plasma and urine samples. Finally, the applicability of the proposed method was evaluated by extraction and determination of LTG in urine and plasma samples.