利用模式识别技术识别鱼肉的鲜度

利用模式识别技术与紫外分光不镀分析法结合，根据鱼肉中的肌苷酸和肌苷的含量对鱼肉鲜度进行了识别，采用人工神经网络法和逐步判别分析法两种模式识别技术，判别结果令人满意。     

测定金鸡纳碱的流动注射化学发光新体系

过氧化氢和高碘酸钠溶液混合能产生弱化学发光,在这一体系中,金鸡纳碱的加入能极大地增强这一化学发光强度,该文对这一化学发光进行了初步的探讨,提出了可能的发光机理,并据此建立了测定金鸡纳碱(奎宁、奎尼丁和辛可宁)的高灵敏度化学发光法;测定奎宁、奎尼丁和辛可宁的线性范围分别为6.0×10-5～1.0×10-2g/L、4.0×10-5～1.0×10-2g/L和1.0×10-3～1.0×10-1g/L,检出限分别为2.1×10-5g/L,1.4×10-5g/L,3.5×10-4g/L;该法适用于奎宁药物的测定.     

Chemiluminescence Flow-Injection System for Rapid Detection of Red Tide Phytoplankton

Abstract

A chemiluminescent flow-injection analysis (FIA) system for the detection of the red tide phytoplankton Chattonella antiqua has been developed based on a Cypridina luciferin analog, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1, 2-α]-pyrazin-3-one (MCLA), which strongly emits light at 465 nm in the presence of superoxide. The system consisted of a two reagent feeding stream, a sample injector, a joint for mixing MCLA and sample, a chemiluminescence (CL) reaction cell, a CL detector and a recorder unit. The response time is approximately 1 min for one measurement cycle. The FIA system has an optimum pH of 10.7. The calibration curves for C. antiqua displayed linearity from 2 × 10³ to 2 × 10⁴ cells ml^?1. When applied to the measurement of C. antiqua, the sensitivity obtained using the FIA system is approximately 10 times higher than that of the cytochrome c method. The FIA system is a rapid practical method for the detection of C. antiqua.     

高灵敏反相流动注射化学发光法测定抗坏血酸

基于抗坏血酸对Ｆｅ２＋－Ｌｕｍｉｎｏｌ－Ｏ２体系化学发光的抑制效应，利用反相流动注射技术，建立了一个测定抗坏血酸的高灵敏化学发光新方法。该法检出限达２×１０－１０ｇ／ｍＬ；抗坏血酸浓度在 １×１０－９～１× １０－６ｇ／ｍＬ范围内与体系化学发光强度减小量呈良好线性相关；相对标准偏差为１．９％（Ｃ＝５×１０－８ｇ／ｍＬ，ｎ＝１１）。     

全固定化试剂流动注射化学发光测定铜

采用离子交换固定法把Ｌｕｍｉｎｏｌ（Ｌｕ），ＣＮ＾－固定在阴离子交换树脂上，串入流动注射系统中，当一定量洗脱剂被注入阴离子交换柱时，洗脱下来的Ｌｕ和ＣＮ＾－与分析物Ｃｕ＾２＋发生化学反应，产生化学发光，实现对Ｃｕ＾２＋的在线检测。本法检出限为１．３×１０＾－９ｇ／ｍＬ，线性范围为４．０×１０＾－９－６．０×１０＾－６ｇ／ｍＬ，ＲＳＤ为３．４％，单次测定在１ｍｉｎ内能完成。已用于井水中铜的测定，结果     

测定利福平的化学发光新体系

基于碱性介质中铜离子催化过氧化氢可氧化利福平产生化学发光这一现象，并结合流动注射分析技术建立起了一种测定利福平的新方法。该方法测定利福平的线性范围为 ４ × １０－７× １０－４ｇ／ｍｌ，方法的检出限为 ７× １０－８ｇ／ｍＬ，７次平行测定 ２ × １０－５ｇ／ｍＬ利福平的相对标准偏差为 ４．９％。成功地用于利福平眼药水中利福平含量的测定。     

FIA-3100流动注射仪数据采集系统的开发及其应用

介绍了一种数据采集系统,阐述了系统组成、实现和主要功能,并结合梯度稀释技术介绍了其在火电厂炉水磷酸根测定中的应用．     

流动体系高性能电流检测器的改进

采用在工作电极（ＷＥ）及辅助电极（ＣＥ）室衬垫尼龙网布的方法改进了本教研室提 出的 ＷＥ与ＣＥ正对面放置型的电流检测［１］。在进样 １００ μＬ样品（Ｂｒ－），流速２ ｍＬ／ｍｉｎ，检 测器电解效率达１８．９％，浓度电流线性范围为１０－２～１０－８ｍｏｌ／Ｌ，重复进样相对标准偏差小 于１％。     

基于光度法的高精度海水pH值测量系统

基于光度法的海水pH值自动测量系统测定速度快,精密度高,是海洋酸化和碳循环研究急需的测量装置.本研究以光度法和流动注射分析技术为基础,通过整合泵阀流路体系、LED光源、流通池和光谱仪,研发了海水pH值自动测量系统.本系统在分析过程中不易产生气泡,利用指示剂在样品中的浓度变化校正指示剂的加入带来的测量偏差,操作简单方便,测量一个样品用时约为1.5 min,精密度为0.0013,准确度为0.0059,可在实验室或调查船中对所采集的海水快速地进行高精度pH值测量.     

Development of an efficient signal amplification strategy for label-free enzyme immunoassay using two site-specific biotinylated recombinant proteins

Constructing a recombinant protein between a reporter enzyme and a detector protein to produce a homogeneous immunological reagent is advantageous over random chemical conjugation. However, the approach hardly recombines multiple enzymes in a difunctional fusion protein, which results in insufficient amplification of the enzymatic signal, thereby limiting its application in further enhancement of analytical signal. In this study, two site-specific biotinylated recombinant proteins, namely, divalent biotinylated alkaline phosphatase (AP) and monovalent biotinylated ZZ domain, were produced by employing the Avitag–BirA system. Through the high streptavidin (SA)–biotin interaction, the divalent biotinylated APs were clustered in the SA–biotin complex and then incorporated with the biotinylated ZZ. This incorporation results in the formation of a functional macromolecule that involves numerous APs, thereby enhancing the enzymatic signal, and in the production of several ZZ molecules for the interaction with immunoglobulin G (IgG) antibody. The advantage of this signal amplification strategy is demonstrated through ELISA, in which the analytical signal was substantially enhanced, with a 32-fold increase in the detection sensitivity compared with the ZZ–AP fusion protein approach. The proposed immunoassay without chemical modification can be an alternative strategy to enhance the analytical signals in various applications involving immunosensors and diagnostic chips, given that the label-free IgG antibody is suitable for the ZZ protein.     

A Rapid Tandem Mass Spectrometric Assay for Determination of Ursolic Acid – Application to Analysis of Ursolic Acid in Four Species of Staphylea L. and Leaves of Staphylea Pinnata L. Gathered During Ontogenesis

Plant extracts of Staphylea L. exhibit a number of biological activities which are presumably attributed to ursolic acid. A rapid and specific tandem mass spectrometric (MS-MS) assay for the quantification of ursolic acid in the leaves of four species of Staphylea L. (Bladdernut) and in the leaves of S. pinnata L. during ontogenesis, was developed and validated. The samples were analyzed by flow injection analysis without chromatographic separation using a transport liquid of methanol/water/formic acid (80:20:0.1 v/v/v) at a flow-rate of 0.2 mL min⁻¹. The run cycle time was ~2-3 min injection-to-injection. Quantification was achieved using multiple reaction monitoring at MRM transition m/z 439 > 203. Calibration curves were linear over the concentration range of 2–20 μg mL⁻¹ with a lower limit of quantification of 2 μg mL⁻¹ (1.8 ± 0.297, RSD: 0.165). Validation data showed that the RSD% values were in the range of 1.8 to 6.8%, whereas the % DEVs ranged from −18 to −2% indicating reasonable and acceptable precision and accuracy, respectively. A recovery percent of 106.8 ± 10.3 of ursolic acid from spiked extracts samples, indicated the specificity and reliability of tandem mass procedure for determination of ursolic acid in the plant extracts. The derived data of sample analysis showed different contents of ursolic acid among various Staphylea species. The highest content of ursolic acid was found in the leaves extract of S. pinnata L. Additionally, the highest amount of ursolic acid accumulated in the leaves of S. pinnata L. was in the August /September period of the year. Smaller amounts of ursolic acid were found in samples collected before and after that time. The results obtained serve as a justification of determining the most appropriate time for collecting plant material as a source of ursolic acid.     

Solid phase extraction for the speciation and preconcentration of inorganic selenium in water samples: A review

Selenium is an essential element for the normal cellular function of living organisms. However, selenium is toxic at concentrations of only three to five times higher than the essential concentration. The inorganic forms (mainly selenite and selenate) present in environmental water generally exhibit higher toxicity (up to 40 times) than organic forms. Therefore, the determination of low levels of different inorganic selenium species in water is an analytical challenge. Solid-phase extraction has been used as a separation and/or preconcentration technique prior to the determination of selenium species due to the need for accurate measurements for Se species in water at extremely low levels. The present paper provides a critical review of the published methods for inorganic selenium speciation in water samples using solid phase extraction as a preconcentration procedure. On the basis of more than 75 references, the different speciation strategies used for this task have been highlighted and classified. The solid-phase extraction sorbents and the performance and analytical characteristics of the developed methods for Se speciation are also discussed.     

Flow injection analysis as a tool for enhancing oceanographic nutrient measurements—A review

Macronutrient elements (C, N and P) and micronutrient elements (Fe, Co, Cu, Zn and Mn) are widely measured in their various physico-chemical forms in open ocean, shelf sea, coastal and estuarine waters. These measurements help to elucidate the biogeochemical cycling of these elements in marine waters and highlight the ecological and socio-economic importance of the oceans. Due to the dynamic nature of marine waters in terms of chemical, biological and physical processes, it is advantageous to make these measurements in situ and in this regard flow injection analysis (FIA) provides a suitable shipboard platform. This review, therefore, discusses the role of FIA in the determination of macro- and micro-nutrient elements, with an emphasis on manifold design and detection strategies for the reliable shipboard determination of specific nutrient species. The application of various FIA manifolds to oceanographic nutrient determinations is discussed, with an emphasis on sensitivity, selectivity, high throughput analysis and suitability for underway analysis and depth profiles. Strategies for enhancing sensitivity and minimizing matrix effects, e.g. refractive index (schlieren) effects and the important role of uncertainty budgets in underpinning method validation and data quality are discussed in some detail.     

Recent developments and applications of screen-printed electrodes in environmental assays—A review

Screen-printed electrodes (SPEs), which are used as economical electrochemical substrates, have gone through significant improvements over the past few decades with respect to both their format and their printing materials. Because of their advantageous material properties, such as disposability, simplicity, and rapid responses, SPEs have been successfully utilised for the rapid in situ analysis of environmental pollutants. This critical review describes the basic fabrication principles, the configuration designs of SPEs and the hybrid analytical techniques based on SPEs. We mainly overview the electrochemical applications of SPEs in environmental analysis over the past 3 years, including the determination of organic compounds, heavy metals and gas pollutants.     

Carbon nanotubes as solid-phase extraction sorbents prior to atomic spectrometric determination of metal species: A review

New materials have significant impact on the development of new methods and instrumentation for chemical analysis. From the discovery of carbon nanotubes in 1991, single and multi-walled carbon nanotubes – due to their high adsorption and desorption capacities – have been employed as sorption substrates in solid-phase extraction for the preconcentration of metal species from diverse matrices. Looking for successive improvements in sensitivity and selectivity, in the past few years, carbon nanotubes have been utilized as sorbents for solid phase extraction in three different ways: like as-grown, oxidized and functionalized nanotubes. In the present paper, an overview of the recent trends in the use of carbon nanotubes for solid phase extraction of metal species in environmental, biological and food samples is presented. The determination procedures involved the adsorption of metals on the nanotube surface, their quantitative desorption and subsequent measurement by means of atomic spectrometric techniques such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry or inductively coupled plasma atomic emission spectrometry/mass spectrometry, among others. Synthesis, purification and types of carbon nanotubes, as well as the diverse chemical and physical strategies for their functionalization are described. Based on 140 references, the performance and general properties of the applications of solid phase extraction based on carbon nanotubes for metal species atomic spectrometric determination are discussed.     

Room temperature phosphorescence in the liquid state as a tool in analytical chemistry

A wide-ranging overview of room temperature phosphorescence in the liquid state (RTPL¹) is presented, with a focus on recent developments. RTPL techniques like micelle-stabilized (MS)-RTP, cyclodextrin-induced (CD)-RTP, and heavy atom-induced (HAI)-RTP are discussed. These techniques are mainly applied in the stand-alone format, but coupling with some separation techniques appears to be feasible. Applications of direct, sensitized and quenched phosphorescence are also discussed. As regards sensitized and quenched RTP, emphasis is on the coupling with liquid chromatography (LC) and capillary electrophoresis (CE), but stand-alone applications are also reported. Further, the application of RTPL in immunoassays and in RTP optosensing—the optical sensing of analytes based on RTP—is reviewed. Next to the application of RTPL in quantitative analysis, its use for the structural probing of protein conformations and for time-resolved microscopy of labelled biomolecules is discussed. Finally, an overview is presented of the various analytical techniques which are based on the closely related phenomenon of long-lived lanthanide luminescence. The paper closes with a short evaluation of the state-of-the-art in RTP and a discussion on future perspectives.     

Antimycobacterial and anticancer activity of newly designed cinnamic acid hydrazides with favorable toxicity profile

A series of twelve novel hybrids of cinnamic acid and thiocarbohydrazones were designed, synthesized in high yield using a simple coupling strategy via acid chlorides, and evaluated for their impact against Mycobacterium tuberculosis (Mtb) and cancer cells survival. Among them, compound 3 demonstrated strong anti-Mtb activity by reducing bacilli survival for>90 % in all three treated Mtb isolates, whereas isoniazid and rifampicin did not. Moreover, compound 3 didn’t affect vitality of HepG-2 cells, implying on advantageous hepatotoxicity profile compared to current therapeutic options for tuberculosis. Compounds 2a and 3b displayed as strong inducers of apoptosis in A549 cells, both activating intrinsic caspase pathway and cell cycle arrest at the G0/G1 phase. Subsequent analyses disclosed differences in their activities, where 3b has ability to induce production of mitochondrial superoxide anions, while 2a significantly inhibited cellular mobility. More importantly, 3b considerably affected viability of HepG-2 and HaCaT cells, whereas 2a had moderate impact only on the later. Molecular modeling studies indicated high permeability and good absorption through the human intestine, and moderate aqueous solubility with poor blood–brain barrier permeability. In summary, our results reveal that novel compounds 3 and 2a represent promising agents for tuberculosis and cancer treatment, respectively, indicating that further investigation needs to be performed to clarify the mechanisms of their anti-Mtb and anticancer activity.