稀土配合物分子印迹荧光探针的制备及检测孔雀石绿的残留

Preparation of Molecularly Imprinted Fluorescent Probe for Rare Earth Complex and Determination of Malachite Green Residue

孔雀石绿是一种人工合成的三苯甲烷类化合物。孔雀石绿的常规检测方法前期处理复杂、耗时长、需要使用大型仪器等缺点导致不能及时的对其进行检测。所以研究出一种能够高效、便捷、快速的检测孔雀石绿残留的方法具有十分重要的意义。分子印迹聚合物(MIPs)是一种多孔隙材料,具有特定的识别位点,可以对特定的目标分子进行识别和吸附。稀土配合物在618 nm处发射荧光,孔雀石绿的最大吸收波长是618 nm,二者重合产生荧光猝灭效应,由此研究出了一种稀土配合物分子印迹荧光探针来检测水产品中的孔雀石绿的方法。利用分子印迹技术固定稀土配合物并吸附水产品中的孔雀石绿,通过在618 nm处检测其荧光猝灭程度来计算水产品中孔雀石绿的具体含量。采用沉淀聚合法,以隐性孔雀石绿为模板,甲基丙烯酸为功能单体,二甲基丙烯酸乙二醇酯为交联剂,改性二氧化硅为核,稀土荧光配合物Eu(MAA)_(3)Phen为荧光物质,在模板∶单体∶交联剂=1∶4∶10,稀土配合物为15 mg,乙腈60 mL的条件下,制备了一种孔雀石绿分子印迹聚合物,通过对其进行TEM和FTIR的扫描分析验证了已经成功合成稀土配合物分子印迹,检测荧光寿命时发现在未加入孔雀石绿前荧光寿命为1094.11μs,而加入孔雀石绿后的荧光寿命为587.49μs,荧光寿命的减少说明孔雀石绿对MIPs的猝灭属于荧光共振能量转移FRET。在验证MIPs的选择性和吸附性能以后,对孔雀石绿进行检测。结果表明,优化条件下聚合物对孔雀石绿的线性范围为0~20μmol·L^(-1),荧光猝灭系数F_(0)/F与孔雀石绿浓度呈现良好的线性关系,线性方程为F_(0)/F=1.008c+0.344(0.1~1μmol·L^(-1),R^(2)=0.991),F_(0)/F=0.587 c+0.570(1~20μmol·L^(-1),R^(2)=0.999),检出限为0.037μmol·L^(-1)(3σ/S,n=9),将其作为荧光探针成功应用于鱼肉中孔雀石绿的检测,加标回收率在95.61%~102.51%范围。说明研究出的稀土配合物分子印迹荧光探针可以便捷、快速、准确地检测出孔雀石绿的残留量。

Malachite green is an artificially synthesized triphenylmethane compound.The disadvantages of conventional detection methods for malachite green,such as complicated pre-treatment,long time-consuming and requiring the use of large instruments,result in the inability to detect promptly.So it is of great importance to invent a method that can detect malachite green residue effectively,rapidly and conveniently.Molecularly Imprinted Polymers(MIPs)are multiporous materials with specific recognition sites that allow the recognition and adsorption of specific target molecules.The rare-earth complexes emit fluorescence at 618 nm,and the maximum absorption wavelength of malachite green is also 618 nm,and the combination of the two produces fluorescence quenching effect.Thereby a rare-earth complex based molecularly imprinted fluorescent probe was developed to detect malachite green in aquatic products.The specific content of malachite green in aquatic products was calculated by detecting the degree of its fluorescence quenching at 618 nm.A malachite green molecularly imprinted polymer was prepared by precipitation polymerization method using cryptic malachite green as a template,methacrylic acid as a functional monomer,ethylene dimethacrylate as a crosslinking agent,modified silica as a core,and the rare-earth fluorescent complex Eu(MAA)_(3) phen as a fluorochrome,in the following conditions∶template∶monomer∶crosslinker=1∶4∶10,Rare earth complexes=15 mg,acetonitrile 60 mL,Molecular imprinting of rare-earth complexes,which have been successfully synthesized,was verified by carrying out TEM and FT-IR scanning analysis,and the fluorescence lifetime when examined was found to be 1094.11μs.However,the fluorescence lifetime after the addition of malachite green was 587.49μs.The decrease of fluorescence lifetime illustrated that the quenching of MIPs by malachite green belonged to the fluorescence resonance energy transfer fret.After verifying the selectivity and adsorption properties of MIPs,malachite green was examined.The linear range of the optimized polymer for malachite green was 0~20μmol·L^(-1),the fluorescence quenching coefficient F_(0)/F shows a good linear relationship with the malachite green concentration,and the linear equation is F_(0)/F=1.008c+0.344(0.1~1μmol·L^(-1),R^(2)=0.991),F_(0)/F=0.587 c+0.570(1~20μmol·L^(-1),R^(2)=0.999)with a detection limit of 0.037μmol·L^(-1)(3σ/S,N=9),which was successfully applied as a fluorescent probe for the detection of malachite green in fish meat,with spiking recoveries in the range of 95.61%~102.51%.These results indicate that the developed MIP based probes can detect malachite green residues easily,rapidly and accurately.