毛细管区带电泳技术快速分离检测爆炸残留物中的无机离子

利用间接紫外毛细管区带电泳方法完成了对爆炸残留物中7种无机离子(K+,NH+4,NO-2,NO-3,SO2-4,ClO-3,ClO-4)的分离检测。阳离子测定采用的缓冲体系为10 mmol/L吡啶（pH 4.5）-3 mmol/L冠醚,K+和NH+4在2.6 min内达到基线分离,检出限分别为0.25 mg/L和0.10 mg/L(S/N=3)。阴离子测定采用的缓冲体系为40 mmol/L硼酸-1.8 mmol/L重铬酸钾-2 mmol/L硼酸钠（pH 8.6）,氢氧化四甲铵为电渗流改性剂,5种阴离子在4.6 min内达到基线分离,检出限为0.10～1.85 mg/L。该方法已成功地应用于实际爆炸物样品种类的判定分析,取得了很好的结果。     

液相色谱-电喷雾电离质谱法检测尿液中的3种合成类固醇药物

研究建立了合成类固醇药物群勃龙、四氢孕三烯炔酮和孕三烯酮的液相色谱-电喷雾质谱的检测方法。尿样经过β-葡萄糖醛酸酶酶解和叔丁基甲醚提取后,采用Zorbax SB-C18分析柱(150 mm×2.1 mm,5 μm),在流动相为pH 3.5的甲酸铵缓冲液-乙腈的条件下进行梯度洗脱,在正离子模式下检测。考察了不同的质谱条件对这类化合物检测结果的影响。建立了人尿液中合成类固醇药物的液相色谱-电喷雾电离质谱的初筛和确证方法。     

离子色谱同时分离测定三氟甲烷磺酸根,氟硼酸根及常见无机阴离子

建立了离子色谱-直接电导检测同时测定三氟甲烷磺酸根,氟硼酸根及常见无机阴离子(F-,Cl-,Br-,NO3-,SO24-)的方法。实验采用Shim-pack IC-A3阴离子交换色谱柱,分别选用对羟基苯甲酸-三(羟甲基)氨基甲烷-硼酸,邻苯二甲酸-三(羟甲基)氨基甲烷,邻苯二甲酸氢钾为淋洗液,考察了淋洗液种类,浓度及色谱柱温度对分离测定三氟甲烷磺酸根,氟硼酸根及常见无机阴离子的影响。最佳色谱条件为:以1.2mmol/L邻苯二甲酸氢钾为淋洗液,柱温30℃,流速1.0mL/min。在此条件下,可同时基线分离7种阴离子,且色谱峰形对称。所测阴离子的检出限(S/N=3)为0.02～1.88mg/L,保留时间和峰面积的相对标准偏差(n=5)分别小于0.17%和2.05%。应用本方法测定离子液体中三氟甲烷磺酸根,氟硼酸根及常见无机阴离子,加标回收率在97.0%～102.8%之间。本方法简单,准确,可靠,具有较好的实用性。     

Beyond labels: A review of the application of quantum dots as integrated components of assays, bioprobes, and biosensors utilizing optical transduction

A comprehensive review of the development of assays, bioprobes, and biosensors using quantum dots (QDs) as integrated components is presented. In contrast to a QD that is selectively introduced as a label, an integrated QD is one that is present in a system throughout a bioanalysis, and simultaneously has a role in transduction and as a scaffold for biorecognition. Through a diverse array of coatings and bioconjugation strategies, it is possible to use QDs as a scaffold for biorecognition events. The modulation of QD luminescence provides the opportunity for the transduction of these events via fluorescence resonance energy transfer (FRET), bioluminescence resonance energy transfer (BRET), charge transfer quenching, and electrochemiluminescence (ECL). An overview of the basic concepts and principles underlying the use of QDs with each of these transduction methods is provided, along with many examples of their application in biological sensing. The latter include: the detection of small molecules using enzyme-linked methods, or using aptamers as affinity probes; the detection of proteins via immunoassays or aptamers; nucleic acid hybridization assays; and assays for protease or nuclease activity. Strategies for multiplexed detection are highlighted among these examples. Although the majority of developments to date have been in vitro, QD-based methods for ex vivo biological sensing are emerging. Some special attention is given to the development of solid-phase assays, which offer certain advantages over their solution-phase counterparts.     

Development and characterization of a magnetic bead-quantum dot nanoparticles based assay capable of Escherichia coli O157:H7 quantification

The development and characterization of a magnetic bead (MB)-quantum dot (QD) nanoparticles based assay capable of quantifying pathogenic bacteria is presented here. The MB-QD assay operates by having a capturing probe DNA selectively linked to the signaling probe DNA via the target genomic DNA (gDNA) during DNA hybridization. The signaling probe DNA is labeled with fluorescent QD₅₆₅ which serves as a reporter. The capturing probe DNA is conjugated simultaneously to a MB and another QD₆₅₅, which serve as a carrier and an internal standard, respectively. Successfully captured target gDNA is separated using a magnetic field and is quantified via a spectrofluorometer. The use of QDs (i.e., QD₅₆₅/QD₆₅₅) as both a fluorescence label and an internal standard increased the sensitivity of the assay. The passivation effect and the molar ratio between QD and DNA were optimized. The MB-QD assay demonstrated a detection limit of 890 zeptomolar (i.e., 10⁻²¹ mol L⁻¹) concentration for the linear single stranded DNA (ssDNA). It also demonstrated a detection limit of 87 gene copies for double stranded DNA (dsDNA) eaeA gene extracted from pure Escherichia coli (E. coli) O157:H7 culture. Its corresponding dynamic range, sensitivity, and selectivity were also presented. Finally, the bacterial gDNA of E. coli O157:H7 was used to highlight the MB-QD assay's ability to detect below the minimum infective dose (i.e., 100 organisms) of E. coli O157:H7 in water environment.     

On-line solid-phase extraction-HPLC-fluorescence detection for simultaneous determination of puerarin and daidzein in human serum

Response surface methodology (RSM) was applied to the optimization of on-line solid-phase extraction (SPE) parameters, and an automated system of on-line SPE coupled with high-performance liquid chromatography (HPLC) with fluorescence detection was developed for the determination of puerarin and daidzein in human serum. The human serum sample of 50 μL was injected into a conditioned C18 SPE cartridge, and the matrix was washed out with acetonitrile-KH₂PO₄-triethylamine buffer (0.01 M, pH 7.4) (3:97, v/v) for 3 min at a flow rate of 0.25 mL/min. Then the target analytes were eluted and transferred to the analytical column. A chromatographic gradient elution was programmed with the mobile phase consisting of acetonitrile and KH₂PO₄-triethylamine buffer, and the analytes were determined with a fluorescence detector at excitation wavelength of 350 nm and emission wavelength of 472 nm, respectively. The proposed method presented good linear relations (0.85-170 μg/mL for puerarin and 0.2-40 μg/mL for daidzein), satisfactory precision (RSD < 8%), and accredited recovery (92.5-107.8%).     

纳米材料电化学与生物传感器——有机微污染物检测新途径

本文介绍了近年来纳米材料电化学与生物传感器在有机微污染物检测中的研究现状,分析了这些传感器中纳米材料修饰电极的特点,重点阐述了纳米材料在有机微污染物检测中的重要作用,列举了一些纳米材料电化学与生物传感器在有机微污染物检测中的应用。最后对纳米材料电化学与生物传感器用于有机微污染物的检测研究进行了简要评述和展望。     

基于场放大进样及Au纳米粒子双重富集用于大肠杆菌检测的毛细管电泳电化学免疫分析法

利用Au纳米粒子作为辣根过氧化物酶(HRP)标记抗体的载体,结合电堆积预富集技术,发展了一种基于场放大进样及Au纳米粒子双重富集的毛细管电泳电化学免疫分析技术用于大肠杆菌的检测.大肠杆菌与酶标抗体免疫反应后直接进行场放大进样预富集,免疫样品快速迁移并堆积在毛细管入口端,同时带负电荷的金纳米粒子向阳极端迁移,在样品与缓冲溶液的界面处吸附样品离子.金纳米粒子作为多酶载体使检测信号进一步放大.以标记在抗体上的HRP催化H2O2氧化邻苯二胺产生的电流信号来检测大肠杆菌.同常规电动进样毛细管电泳相比,该双重富集技术可使灵敏度提高1400倍.该方法对大肠杆菌检测的线性范围为2.0～2000.0 cfu mL-1,检出限为1.0 cfu mL-1,实现了对扇贝样品中大肠杆菌的快速、灵敏检测.     

2,5-二(4’-羧基苯基)-1-苯基吡咯对胺的“点亮”荧光检测

基于水溶性2,5-二(4’-羧基苯基)-1-苯基吡咯的羧酸钠盐(TPP-2COONa)具有质子化荧光淬灭、去质子化荧光增强的特征.在研究了TPP-2COONa的紫外吸收光谱和荧光发射光谱对pH的响应规律的同时,以此为荧光探针,证实了TPP-2COOH对于多种胺类(氨水、二异丙胺、异丙胺和三乙胺)荧光增强响应明显,而对芳香胺(吡咯、苯胺、吡啶)没有任何荧光响应,其中对于氨水最为敏感,在很窄的pH区间和低浓度范围内荧光强度大幅度增长,体现了该探针对于氨水具有良好的选择性和灵敏度,并可简易实现"在线裸眼检测".     

高效毛细管电泳-二极管阵列检测法测定土壤中的苯酚

建立了高效毛细管电泳-二极管阵列检测器测定土壤样品中苯酚的方法,研究了检测波长、缓冲体系、缓冲体系的pH值及浓度、分离电压、进样时间及压力等因素。结果表明,在温度25℃、pH=10的30mmol/L K2HPO4+0.5mmol/L十四烷基三甲基溴化铵(TTAB)运行缓冲溶液、检测波长206nm、20kV运行电压、负电压模式、0.5psi进样10s条件下,苯酚在4.2到4.4min内出峰,迁移时间和峰面积的相对标准偏差(RSD)分别为0.11%、0.28%,检出限(3Sb/Sx)为0.01mg/L。该方法成功地应用于土壤中苯酚的测定,其回收率为98.4%。