分子印迹固相萃取-超高效液相色谱串联质谱法测定猪肉中磺胺二甲氧嗪EI北大核心CSCD

建立了基于分子印迹聚合物(MIPs)为固相萃取填料的固相萃取技术结合超高效液相色谱串联质谱法(MISPE-UPLC-MS/MS)检测猪肉中磺胺二甲氧嗪。以磺胺二甲氧嗪为模板分子,三氟甲基丙烯酸为功能单体,采用沉淀聚合法制备了分子印迹固相萃取填料,并对萃取净化条件进行了优化。在优化的提取条件和分析条件下,对猪肉肌肉样品中磺胺二甲氧嗪进行分析,其检出限为1.225μg/kg;定量限为4.083μg/kg;双水平回收率在81.4%~106.9%;RSD为3.7%和12%。与M CX柱净化相比,分子印迹固相萃取柱能够有效去除基质效应,分离待测物与杂质。     

分子印迹固相萃取-超高效液相色谱串联质谱法测定猪肉中磺胺二甲氧嗪

建立了基于分子印迹聚合物(MIPs)为固相萃取填料的固相萃取技术结合超高效液相色谱串联质谱法(MISPE-UPLC-MS/MS)检测猪肉中磺胺二甲氧嗪。以磺胺二甲氧嗪为模板分子,三氟甲基丙烯酸为功能单体,采用沉淀聚合法制备了分子印迹固相萃取填料,并对萃取净化条件进行了优化。在优化的提取条件和分析条件下,对猪肉肌肉样品中磺胺二甲氧嗪进行分析,其检出限为1.225μg/kg;定量限为4.083μg/kg;双水平回收率在81.4%~106.9%;RSD为3.7%和12%。与M CX柱净化相比,分子印迹固相萃取柱能够有效去除基质效应,分离待测物与杂质。     

分子印迹固相萃取-高效液相色谱法测定饲料中磺胺类药物

建立了基于分子印迹聚合物(MIPs)为吸附剂的固相萃取技术结合高效液相色谱检测饲料中5种磺胺类药物(SAs)的方法。以磺胺嘧啶为模板,采用紫外光引发合成MIPs,以MIPs作为吸附剂制备固相萃取柱,并对上柱、淋洗和洗脱等萃取条件进行了优化。在优化的条件下,5种SAs的检出限为0.14～0.23 mg/kg;定量限为0.38～0.47 mg/kg;平均回收率在72.1%～89.3%之间;批内与批间相对标准偏差分别小于7.9%和9.2%。与碱性氧化铝柱净化相比,分子印迹固相萃取柱净化后杂质更少,选择性更好,方法的定量限更低。     

快速溶剂萃取–高效液相色谱法测定禽蛋中磺胺嘧啶

建立快速溶剂萃取–高效液相色谱法测定禽蛋中磺胺嘧啶残留的方法。用单因素和正交试验对禽蛋中磺胺嘧啶的萃取条件进行优化,确定了最佳萃取条件:以甲醇为萃取剂,在130℃循环萃取4次,冲洗体积分数为80%,萃取时间为25 min。色谱柱为Hypersil ODS2柱(4.6 mm×250 mm,5μm),流动相为甲醇–0.5%冰乙酸(25∶75),流量为1.0 m L/min,检测波长为265 nm。磺胺嘧啶的质量浓度在0.025~0.500 mg/m L范围内与色谱峰面积呈良好的线性关系,相关系数r=0.999 5,检出限为0.5μg/kg。加标回收率在83.0%~88.2%之间,测定结果的相对标准偏差为2.2%(n=9)。方法的精密度、准确度和基质效应均符合禽蛋样品检测要求,可用于禽蛋中磺胺嘧啶含量的测定。     

聚合物整体柱微萃取-高效液相色谱法检测鸡蛋中的磺胺嘧啶和磺胺二甲嘧啶残留

建立了鸡蛋中磺胺嘧啶和磺胺二甲嘧啶残留量的聚合物整体柱微萃取和高效液相色谱检测方法。以聚(甲基丙烯酸-乙二醇二甲基丙烯酸酯)毛细管整体柱作为萃取装置。为了得到较高的萃取效率,优化了影响萃取效率的参数(萃取流速、萃取体积、样品基质pH值)。样品经过匀浆、乙醇提取、磷酸盐缓冲溶液稀释、离心等步骤后直接进行萃取。鸡蛋中磺胺嘧啶和磺胺二甲嘧啶的检出限分别为11.2 ng/g和8.8 ng/g,在50～5000 ng/g的浓度范围内具有良好的线性关系。加标回收率大于65%,日内、日间测定的相对标准偏差不高于8.2%。结果表明,方法简单、快速、灵敏度高,适用于鸡蛋中磺胺嘧啶和磺胺二甲嘧啶的常规分析。     

加替沙星分子印迹聚合物的制备及其应用

以加替沙星为模板分子,采用溶胶-凝胶分子印迹技术,合成具有分子识别作用的新型有机-无机杂化分子印迹聚合物,对其进行吸附性能研究证明了印迹聚合物对加替沙星的专一吸附性能。以该印迹聚合物为固相萃取材料填充固相萃取柱,优化固相萃取条件,结合超高效液相色谱法,对牛奶样品进行检测。建立了分子印迹固相萃取方法,分离富集并检测牛奶中的加替沙星,其回收率为79.87%,富集倍数为38,高于市售C18柱,具有一定的实际应用价值。     

分子印迹化学发光传感器在线检测牛肉与鸡肉组织中残留的磺胺嘧啶

以分子印迹作为识别体,制成高灵敏度和高选择性的化学发光传感器在线检测牛肉与鸡肉组织中残留的磺胺嘧啶。磺胺嘧啶作为靶分子,通过悬浮聚合制备了1～10μm的分子印迹聚合物。将分子印迹聚合物装入聚四氟乙烯管中,作为固相萃取柱,并联在八通阀上,用于在线选择吸附磺胺嘧啶。在最佳条件下,测得磺胺嘧啶线性范围7.0×10–9～9.0×10–7g/mL,方法的检出限为(3σ)2×10–10g/mL,11次平行测定3.0×10–8g/mL的磺胺嘧啶溶液的化学发光强度相对标准偏差为3.4%。方法能够用于检测肉类产品中残留的磺胺嘧啶。     

固相萃取–高效液相色谱法测定地表水中4种磺胺类抗生素

建立固相萃取–高效液相色谱法测定地表水中磺胺嘧啶、磺胺二甲嘧啶、磺胺氯哒嗪、醋磺胺甲恶唑4种磺胺类抗生素。样品采用HLB柱进行萃取富集,流动相为甲醇–水(体积比为20∶80),流量为0.5 m L/min,用SPD检测器检测,检测波长为270 nm;采用外标法定量。4种磺胺类抗生素质量浓度在4~160 ng/L范围内与色谱峰面积的线性关系良好,相关系数不低于0.998 2,方法检出限为1.0~1.7 ng/L,样品加标回收率为75.2%~97.4%,测定结果的相对标准偏差为2.8%~6.1%(n=7)。该方法操作简便,灵敏度高,可用于地表水中磺胺类抗生素的检测。     

固相萃取–高效液相色谱法同时测定饲料中4种磺胺类药物残留

建立固相萃取–高效液相色谱法同时测定饲料中的磺胺嘧啶、磺胺二甲嘧啶、磺胺甲恶唑、磺胺喹恶啉4种磺胺类药物残留的方法。样品用乙腈提取,然后用碱性氧化铝固相萃取柱净化,色谱柱为C_(18)柱(250 mm×4.6mm,5μm),以水–乙腈(体积比为75∶25,含0.3%乙酸)为流动相,流量为1.0 mL/min,检测波长为270 nm。4种磺胺类药物的质量浓度在1~10μg/mL范围内与其色谱峰面积呈良好的线性,相关系数均大于0.999,检出限为0.025~0.133μg/g。磺胺类药物测定结果的相对标准偏差为0.22%~0.30%(n=6),样品加标回收率为93.6%~106.7%。实际饲料样品中均未检出这4种磺胺组分。该方法具有干扰少,灵敏度高,重复性好的优点,可以作为饲料中的磺胺类药物残留的一种检测方法。     

分散液液微萃取-高效液相色谱法测定水中磺胺类药物残留

建立了分散液液微萃取-高效液相色谱法测定水样中氨苯磺胺、磺胺嘧啶,磺胺二甲基嘧啶3种磺胺药物残留的检测方法。对萃取剂、分散剂的种类和体积、pH、盐浓度等影响萃取效率的因素进行了优化。在最优的萃取条件下,3种抗菌药的测定线性范围为1~1000μg/L,r≥0.9997,检出限为0.07~0.25μg/L(S/N=3)。应用于5种不同水样中磺胺类抗菌药残留的分析,目标分析物的加标回收率在82.0%~104.0%之间,相对标准偏差小于5.9%。     

Separation and determination of ciprofloxacin in seawater,human blood plasma and tablet samples using molecularly imprinted polymer pipette‐tip solid phase extraction and its optimization by response surface methodology

By synthesizing a molecular imprinted polymer as an efficient adsorbent, ciprofloxacin was micro‐extracted from seawater, human blood plasma and tablet samples by pipette‐tip micro solid phase extraction and determined spectrophotometrically. Response surface methodology was applied with central composite design to build a model based on factors affecting on microextraction of ciprofloxacin; including volume of eluent solvent, number of extraction cycles, number of elution cycles, and pH of sample. Other factors that affect extraction efficiency, such as type of eluent solvent, volume of sample, type, and amount of salt were optimized with one‐variable‐at‐a‐time method. Under optimum extraction condition, pH of sample solution was 7.0, volume of eluent solvent (methanol) was 200 µL, volume of sample solution was 10 mL, and the number of extraction and elution cycles was five and seven, respectively, amount of Na₂SO₄ (as salt) and MIP (as sorbent) were optimized at 150 and 2 mg, respectively. The linear range of the suggested method under optimum extraction factors was 5–150 µg/L with a limit of detection of 1.50 µg/L for the analyte. Reproducibility of the method (as relative standard deviation) was better than 7%.     

Room temperature fabrication of magnetic covalent organic frameworks for analyzing sulfonamide residues in animal-derived foods

A magnetic solid phase extraction method based on magnetic covalent organic frameworks (TpBD@Fe₃O₄; 2,4,6-triformylphloroglucinol (Tp) and benzidine (BD)) combined with high performance liquid chromatography has been developed to detect the sulfonamides including sulfadiazine, sulfamerazine, sulfamethazine, and sulfamethoxazole in milk and meat. TpBD@Fe₃O₄ were synthesized at room temperature under mild reaction conditions with a simple and rapid operation. The TpBD@Fe₃O₄ exhibited higher extraction efficiency because of the π–π and electrostatic interactions between the benzene ring structure of the TpBD and the sulfonamide molecules. The extraction conditions including the dosage of adsorbents, the type and dosage of eluent, the elution time, and the pH of the sample solution were fully optimized. The detection results showed good linearity over a wide range (50–5 × 10⁴ ng/mL) and low detection limits (3.39–5.77 ng/mL) for the sulfonamide targets. The practicability of this magnetic solidphase extraction-high-performance liquid chromatography method was further evaluated by analyzing milk and meat samples, with recoveries of the targets of 71.6–110.8% in milk and 71.9–109.7% in pork. The successful detection of sulfonamides residues has demonstrated the TpBD@Fe₃O₄ excellent practical potential for analyzing pharmaceutical residues in animal-derived foods.     

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.     

Graphene as Solid-Phase Extraction Adsorbent for CZE Determination of Sulfonamide Residues in Meat Samples

A solid-phase extraction (SPE) using graphene as adsorbent coupled with capillary zone electrophoresis method was developed for the determination of four sulfonamide residues (sulfadimidine, sulfadimethoxine, sulfathiazole and sulfadiazine) in meat sample. Several condition parameters, such as elution solvents and volumes, sample pH and sample volume were optimized to obtain high SPE recoveries and extraction efficiency. Intra-day precisions of sulfonamides were in the range of 2.5–2.6 % and the inter-day precisions of sulfonamides were in the range of 2.6–3.4 %. Recoveries were 60.9–66.6 % for sulfadiazine and 86.1–111.4 % for other three sulfonamides in spiked meat sample. The developed method was successfully applied for the determination of sulfonamides in meat samples.     

Simultaneous determination of multiveterinary drug residues in pork meat by liquid chromatography‐tandem mass spectrometry combined with solid phase extraction

An LC‐MS/MS method developed for simultaneous analysis of 54 veterinary drug residues of six families in pork meat samples, including sulfanilamide, nitroimidazoles, quinolones, macrolide antibiotics, lincosamides, and praziquantel. The pork meat sample was prepared by extraction with ACN, and clean‐up on a C₁₈ SPE cartridge. The sample was separated on a C₈ column and eluted with ACN, methanol, and formic acid. The MS/MS detector is operated in the multiple reaction monitoring mode, acquiring two specific precursor‐product ion transitions per target compound. The method showed excellent linearity (R² ≥ 0.99) and high precision (relative SD, RSD ≤ 19.8%) for all compounds. The method quantification limits of 54 veterinary drug residues were in the range of 0.3–3.0 μg/kg. Recoveries for most analytes based on matrix‐matched calibration in matrices were 20.9–121.0%. This method has been successfully applied for analysis of more than 100 pork meat samples from the local market; five of the 54 drugs were detected.     

Determination of 10 sulfonamide residues in meat samples by liquid chromatography with ultraviolet detection

A liquid chromatography (LC) method is described for the simultaneous determination of 10 commonly used sulfonamide drug residues in meat. The 10 sulfonamide drugs of interest were sulfadiazine, sulfathiazole, sulfamerazine, sulfadimidine, sulfamethizole, sulfamonomethoxine, sulfachloropyridazine, sulfadoxine, sulfadimethoxine, and sulfaquinoxaline. The residues were extracted with acetone-chloroform (1 + 1). Sulfonamides were quantitatively retained in the extracting solution and afterwards eluted from a cation-exchanger solid-phase extraction cartridge with a solution of methanol-aqueous ammonia. The solution was dried, reconstituted with 5 mL methanol and filtered before analysis by LC-ultraviolet using a C18 column with a mobile phase gradient of potassium dihydrogen phosphate buffer, pH 2.5, and methanol-acetonitrile (30 + 70, v/v). The method was applied to cattle, swine, chicken, and sheep muscle tissues. The validation was performed with a fortified cattle meat sample at level of 100 ppb, which is the administrative maximum residue limit for sulfonamides in the European Union. The limit of quantitation for all sulfonamides was between 3 and 14 ppb. Recovery was evaluated for different meat matrixes. The mean recovery values were between 66.3% for pork meat samples and 71.5% for cattle meat samples.     

Room temperature ionic liquid-mediated molecularly imprinted polymer monolith for the selective recognition of quinolones in pork samples

A novel molecularly imprinted polymer monolith was prepared by the room temperature ionic liquid-mediated in situ molecular imprinting technique, using norfloxacin (NOR) as the template, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker. The optimal synthesis conditions and recognition properties of NOR-imprinted monolithic column were investigated. The results indicated that the imprinted monoliths exhibited good ability of selective recognition against the template and its structural analog. Using the fabricated material as solid-phase extraction sorbent, a sample pre-treatment procedure of molecularly imprinted solid-phase extraction coupling with HPLC was developed for determination of trace quinolone residues in animal tissues samples. The recoveries ranging from 78.16 to 93.50% for eight quinolones antibiotics such as marbofloxacin, NOR, ciprofloxacin, danofloxacin, difloxacin, oxolinic acid, flumequine and enrofloxacin were obtained.     

A high selective ion‐imprinted polymer grafted on a novel nanoporous material for efficient gold extraction

In this work, for the first time, an ion‐imprinted polymer was developed for selective extraction and determination of gold ions. To increase the sorbent efficiency, this polymer was coated on a novel nanoporous carbon‐based material, carbohydrate‐derived Max‐Planck Gesellschaft 1, which is also the first example of grafting imprinted polymer on nanoporous‐carbon material. These particles were applied successfully for preconcentration of ultratrace amount of gold ions, following determination by flame atomic absorption spectrometry. Some effective factors on the efficiency of gold ions extraction, such as concentration and volume of eluent, sample and eluent flow rates, and also effect of interfering ions especially palladium and platinum ions, were investigated. The LOD was determined to be 0.27 ng/mL. Furthermore, the precision of the method was calculated to be 2.14% under optimal conditions with recovery more than 97.3%. The technique was also used to determine the concentration of gold ions in mine stone samples with satisfactory results. The accuracy of this method was investigated by determination of gold ions concentrations in several reference materials with certified gold content.     

Dual‐templates molecularly imprinted monolithic columns for the evaluation of serotonin and histamine in CEC

To extend the application of molecularly imprinted polymers, the dual‐templates molecularly imprinted monolithic columns were developed in a capillary format. Two templates serotonin and histamine were simultaneously imprinted using two different functional monomers such as methacrylic acid (MAA) and methylenesuccinic acid (MSA) in a mixture of ethylene glycol dimethacrylate (EDMA) as a cross‐linker and AIBN as polymerization initiator dissolved in DMF as porogen. The resulting molecular imprinted polymers (MIPs) were characterized based on their performance in the CEC separation of two imprinted templates. The optimization parameters such as pH, ACN composition, and concentration of the eluent were varied to achieve best resolution and efficiency for CEC separation of templates with each MIP column. It was found that the MIP monolith column fabricated using MSA offered better resolution and separation efficiency compared to column fabricated with MAA. This work utilized the dual‐templates imprinting approach successfully and broadens the scope of multi‐templates imprinting capabilities in capillary format in CEC application.