流动注射化学发光传感器测定抗坏血酸

基于抗坏血酸抑制ＫＭｎＯ４－鲁米诺体系化光反应这一效应，设计出一种简便，快速，灵敏度高的消耗型化学发光抗坏血酸传感器。该传感器线性响应范围为１．０＊１０＾－５－４．０＊１０＾－３ｇ／Ｌ；相对标准偏差为２．３％（１．０＊１０＾－４ｇ／Ｌ，ｎ＝１１）；     

Spectrofluorimetric Determination of Nanogram Amounts of Cadmium with Benzyl-2-Pyridylketone 2-Pyridylhydrazone

Abstract

A rapid, simple and sensitive spectrofluorimetric determination of cadmium based on the formation of a fluorescent chelate with benzyl-2-pyridylketone 2-pyridylhydrazone is described. In darkness, the fluorescence development is instantaneous and remains stable for 1 h. The detection limit is 11 ppb. The influence of reaction variables and the effect of foreign ions are discussed.     

Re-Examination of the Cadmium Reduction Method and Optimisation of Conditions for the Determination of Nitrate by Flow Injection Analysis

The present paper re-examines the widely used flow injection method for nitrate which is based on heterogeneous reduction of nitrate with copperized cadmium followed by spectrophotometric detection of nitrite formed. The thorough investigation presented here has shown that the reduction step is very critical as far as conversion rate, possible further reduction of nitrite and long-term stability of the reductor column is concerned. The reasons for inconsistent and irreproducible results mentioned in original papers and often obtained in routine applications could be traced back to the way the reductor material had been prepared, the chemical conditions under which reduction takes place (i.e. pH and concentration of complexing agents) and the poisoning of the cadmium surface by sample constituents. The concomitant reduction of dissolved oxygen has been identified as a potential problem causing loss of pH control (due to in-situ generation of hydroxide). De-oxygenation of the carrier solution was found to be a means to overcome this problem with the additional advantages of increasing the lifetime of the reductor column and significantly reducing the concentration of cadmium ions in the waste stream. The role of particle size and column dimension as well as sample residence time within the reductor column on reduction efficiency and sample dispersion has also been investigated.     

Integrated Retention/Spectrophotometric Detection Method for the Determination of Formaldehyde

Abstract

An integrated-sensor method for the determination of formaldehyde based on retention of the reaction product of the analyte with p-rosaniline and sulfite in a flow-cell packed with Dowex 1-X-8 anion exchange resin was developed. The method has a good selectivity with a detection limit of 0.3 μg ml^?1 (1 ml sample) or 75 ng ml^?1 (2 ml sample), and a linear range between 1–30 μg ml^?1. The relative standard deviations (n = 11) were 2.8 and 1.3% for 2 and 20 μg ml^?1 formaldehyde, respectively. Depending on the working conditions, the sampling frenquency ranged between 10 and 18 h^?1. The method was applied to the determination of formaldehyde in well water.     

Flow Injection Spectrofluorimetric Method for the Determination of Cadmium

A novel fluorescent reagent, o-vanillin furoylhydrazone (OVFH), was synthesized, and its infrared spectrum, elemental analysis and dissociation constant are reported. The reaction between Cd²⁺ and OVFH produces an intensely fluorescent complex in ethanol-water medium of pH 10.00, and this finding has led to a simple, rapid, and sensitive flow injection (FI) spectrofluorimetric method for on-line determination of Cd²⁺. Under the optimum experimental conditions, the fluorescent complex had excitation and emission maxima at 393 and 494nm, respectively. The linear range is from 0.025 to 8.0µgmL^–1 of Cd²⁺, the detection limit is 7.6µgL^–1 and the maximum sampling rate is 80h^–1. The effect of interferences was studied. The method was successfully applied to the determination of cadmium in environmental samples.     

Determination of Enzymatic Activities Based on an Optical Flow-Through p-Nitrophenol Sensor

Abstract

An optical flow-through biosensor based on the transient retention of p-nitrophenol on an ion-exchange support packed in the flow cell is presented. The approach was applied to the determination of the activity of some enzymes which catalyze the conversion of p-nitrophenyl-derivatives into p-nitrophenol. The method was first developed for determination of p-nitrophenol yielding a linear range between 0.1–5 μg/mL (r² = 0.9922, r.s.d.% less than 2.5), then, it was also applied to the determination of β-D-glucuronidase activity in serum, with a linear range between 0.1–20 U/L (r² = 0.9976, r.s.d.% less than 3.0), and a sampling frequency of 20 h^?1. The application of the method to the determination of the enzyme activity in serum samples provided results consistent with those obtained by a conventional method and recoveries within 95–104%.     

离子印迹荧光传感器选择性检测镉离子

该文运用离子印迹技术,结合表面修饰方法以2-萘基丙烯酸酯为荧光配体,聚偏氟乙烯(PVDF)膜为支撑介质,在二甲基亚砜中于65℃下热引发聚合得到镉离子荧光印迹传感器.该荧光印迹传感器在中性条件下对镉离子表现出良好的选择性和抗干扰能力,检出限为5.5×10-7mol/L,与ICP - MS法无显著性差异.循环使用10次的相...     

酶催化光度法测定异丙肾上腺素

试验表明:在pH 9.5氨水-氯化铵缓冲介质中,牛血红蛋白对过氧化氢与酸性络蓝K的氧化还原反应的催化作用因异丙肾上腺素的存在而被抑制,而且其抑制率与异丙肾上腺素的浓度在8.1×10~(-8)～1.2×10~(-5)mol·L~(-1)范围内呈线性关系,其检出限(3S/N)为2.2×10~(-9)mol·L~(-1)。据此,提出了一种简单而灵敏的测定异丙肾上腺素的酶催化光度法。此方法已用于盐酸异丙肾上腺素注射液中异丙肾上腺素含量的测定,并以此样品为基体用标准加入法作回收试验,测得回收率在92.8%～105.4%之间,测定值的相对标准偏差(n=5)在2.6%～5.8%之间。     

基于反射式光度传感器的自动光度滴定仪的研制及应用

研制了一种以颜色变化为滴定终点的自动光度滴定仪,仪器以光度传感器为核心,包括光度探头、滴定装置、AT89S52单片机、电磁阀、二极管和磁力搅拌器等部件。传感器采用开放设计,对溶液吸光度变化反应迅速。仪器用于红醋酸度的测定,所得结果与电位滴定分析法结果相符。     

石墨炉原子吸收法检测胎盘镉水平

建立了硝酸消化、石墨炉原子吸收法（GFAAS）测定胎盘中镉含量的方法。取0．3g胎盘于110℃烤箱烘烤1h,在80℃水浴下HNO3、H202顺序消化1h,消化后定容至2mL;D2灯校正背景,样本基体匹配、标准曲线法测定。结果表明,此法相对标准偏差〈10％,回收率为89．4％～91．2％,此检测方法稳定,简便可行,胎盘取材方便,对新生儿无损伤,对新生儿镉负荷的检测评估具有一定的意义。     

Photometric Determination of Iron in Pharmaceutical Formulations Using Double-Beam Direct Injection Flow Detector

In this work, an innovative, flow-through, double-beam, photometric detector with direct injection of the reagents (double-DID) was used for the first time for the determination of iron in pharmaceuticals. For stable measurement of the absorbance, double paired emission-detection LED diodes and a log ratio precision amplifier have been applied. The detector was integrated with the system of solenoid micro-pumps. The micro-pumps helped to reduce the number of reagents used and are responsible for precise solution dispensing and propelling. The flow system is characterized by a high level of automation. The total iron was determined as a Fe(II) with photometric detection using 1,10-phenanthroline as a complexing agent. The optimum conditions of the propose analytical procedure were established and the method was validated. The calibration graph was linear in the range of 1 to 30 mg L⁻¹. The limit of detection (LOD) was 0.5 mg L⁻¹. The throughput of the method was 90 samples/hour. The repeatability of the method expressed as the relative standard deviation (R.S.D.) was 2% (n = 10). The method was characterized by very low consumption of reagents and samples (20 μL each) and a small amount of waste produced (about 540 µL per analysis). The proposed flow method was successfully applied for determination of iron in pharmaceutical products. The results were in good agreement with those obtained using the manual UV-Vis spectrophotometry and with values claimed by the manufacturers. The flow system worked very stably and was insensitive to bubbles appearing in the system.     

A Generic Design of a Flow-Through Potentiometric Sensor Array

 In this paper, a flow-through potentiometric microsensor is described which is based on semi-permeable tubing. The ion selective electrodes proposed are of the liquid membrane type in which a dialysis tube captures the ion selective cocktail. Ion selective sensors and a reference electrode based on the same design were constructed by guiding a 0.3 mm diameter dialysis tube through a cavity precision machined in Perspex?. Commercia lly available ionophore or ion-exchanger cocktails were applied to provide ion selectivity whilst a saturated KCl solution was used in the reference electrode. A number of flow-through microsensors selective to different ions (Na, K, Li, pH) were constructed and tested. Each showed good performance in a broad range of concentrations. Advantages of the proposed approach are the generic technology to make sensors with incorporate d reference electrodes, capable of measuring a wide variety of analytes for which cocktails are readily available and the fact that sub-microliter amounts of sample can be measured. Secondly, in comparison to other sensors applied in microchannels, the impedance of the flow-through sensor is much smaller because of the relatively large sensing surface formed by the tube wall. Moreover, the use of dialysis tubing enables easy integration with a so-called microdialysis probe for in-vivo sampling of the blood stream or subcutaneous tissue. Received December 6, 1999. Revision March 24, 2000.     

流通池光度滴定法应用：多元络合物组成的快速测定

用流通光度滴定法建立了测定多元络合物组成的快速方法。方法简单，仅用中心离子和配体各一个标准溶液。经测定几组络合物体系，实验结果与文献值完全一致。     

CTMAB-Peregal O存在下锌镉的FIA同时测定

混合表面活性剂CTMAB-Peregal O对Zn~(2+)和Cd~(2+)与4-(2-吡啶偶氮)一问苯二酚的配合反应有协同增敏作用。由配合反应测得Zn~(2+)和Cd~(2+)的总量,用二乙基二硫代氨基甲酸钠掩蔽Cd~(2+)后,可测得Zn~(2+)量,再由计算求得Cd~(2+)量。研究了应用连续交替注入技术流动注射光度法同时测定Zn~(2+)和Cd~(2+)的方法。Zn”和Cd~(2+)的浓度分别在0～0.6μg/g和0～1.0μg/g时符合比耳定律。相对标准偏差<1.0%,进样频率180次/h。曾用此法测定了西湖水和工业废水中的Zn~(2+)和Cd~(2+),结果满意,并初步探讨了协同增敏作用的机理。     

Simultaneous Determination of Paracetamol, Caffeine and Propyphenazone in Pharmaceuticals by Means of a Single Flow-Through UV Multiparameter Sensor

 For the first time, a multiparameter-responding flow-through system with solid phase UV spectrophotometric detection (a multiparameter optosensor) is described for the simultaneous determination of a mixture of three active principles (paracetamol, caffeine and propyphenazone) using univariate calibration. Quantitation is based on the direct intrinsic UV absorbance measurements of the analytes when they reach the sensing zone (C₁₈ silicagel) placed in the flow cell of the FIA system. Because of the strong spectral overlap showed by these analytes, a temporary sequentiation in their arrival to the sensing zone is required from one only injection. It is achieved by means of an on-line simultaneous retention of two of them (caffeine and propyphenazone) on a minicolumn filled with C₁₈ silica-gel placed before the solid phase UV transductor, while paracetamol passes through the minicolumn and develops its transitory signal. Then, caffeine and propyphenazone are successively eluted from the column using two different methanol/water solutions (10% and 50% v.v respectively) and reach sequentially the sensing zone, developing their respective signals. Thus, with a single injection very good linear responses were obtained in the ranges 25–350 (paracetamol), 5–75 (caffeine) and 15–150 (propyphenazone) μg mL⁻¹. Detection limits ranging from 0.65 to 7.5 μg mL⁻¹ were found. Application of the detector to the successfully determination of the analytes in commercial pharmaceuticals was demonstrated. Correspondence: Department of Physical and Analytical Chemistry, Faculty of Experimental Sciences, University of Jaén, Paraje Las Lagunillas, E-23071 Jaén, Spain. e-mail: amolina@ujaen.es Received June 15, 2002; accepted November 12, 2002     

三氮烯类试剂在镉光度分析中的应用

介绍了1985年以来三氮烯类显色剂在光度分析中的应用,着重介绍了灵敏度高,选择性好的显色剂。     

流动注射—二极管阵列检测分光光度法同时测定铅和镉

建立流动注射－电荷耦合器件二极管阵理分光光度法装置，研究了以ｍｅｓｏ－四（４－三甲铵苯基）卟啉为显色剂同时测定铅和镉的方法，镉和铅测定的线性范围为０～２．０ｍｇ／Ｌ和０～２．５ｍｇ／Ｌ镉的检出限为０．０１４ｍｇ／Ｌ，铅为０．０１５ｍｇ／Ｌ。进样频率为６０次／ｈ，对合成样品和陶瓷食具容器浸泡液中铅和镉进行了同时测定，获得满意的结果，样品的平均标准加入回收率为１００．９％，相对标准偏差小于８．８％。     

Tripodal Cadmium Complex and Macrocyclic Ligand Based Sensors for Phosphate Ion Determination in Environmental Samples

Tripodal cadmium complex of hydrotris(3‐phenyl‐5‐methylpyrazolyl)borate (I₁) and macrocyclic ligand 5,7 : 12,14 : 19,21 : 26,28‐Bzo₄‐[28]‐5,13,19,27‐tetraene‐8,11,22,25‐N_4–1,4,15,18‐O₄ (I₂), have been synthesized and characterized by IR, ¹H NMR, Mass and elemental analysis. Spectroscopic investigations indicate high affinity of these receptors for dihydrogen phosphate ion. Polyvinyl chloride (PVC) based membranes of (I₁) and (I₂) using hexadecyl trimethylammonium bromide (HTAB) as cation discriminator and dibutylpthalate (DBP), tributyl phosphate (TBP), dioctylsebacate (DOS), and o‐nitrophenyloctyl ether (o‐NPOE), as plasticizing solvent mediators were prepared and investigated as H₂PO selective sensors. The best performance was shown by the membrane of composition (w/w) (I₂) (5%):PVC (31%) : DBP (61.5%):HTAB (2.5%). This sensor works well over a wide concentration range 2.1×10^?7 to 1.0×10^?2 M with Nernstian compliance (59.0 mV decade^?1 of activity) with a fast response time of 14 s and showed good selectivity for dihydrogen phosphate ion over a number of anions. The sensor exhibits good reproducibility (SD±0.3 mV) and could be used successfully for the determination of phosphate in soil water samples.     

Molecular Imprinting-Chemiluminescence Sensor for the Determination of Prulifloxacin

Abstract

A selective molecular imprinting-chemiluminescence sensor is developed for the determination of prulifloxacin by using a prulifloxacin-imprinted polymer as recognition material and the cerium(IV)/sodium thiosulfate/prulifloxacin chemiluminescence reaction as the detection system. The linear response range of the sensor is from 8.0 × 10^?8 to 7.0 × 10^?6 mol L^?1 with a detection limit of 2.0 × 10^?8 mol L^?1. The relative standard deviation for 5.0 × 10^?7 mol L^?1prulifloxacin solution is 1.3% (n = 7). This sensor has been applied to the determination of prulifloxacin in urine samples, and the results obtained are satisfactory.     

以氯酸钾氧化盐酸氯丙嗪为指示反应催化光度法测定痕量钒

钒对KClO_3氧化盐酸氯丙嗪(CPH)的反应具有极高的催化活性。通过对分析体系的综合研究,给出了测定的最佳条件。本方法灵敏,快速、测定的下限可达2ppb,常见的近二十种离子不干扰钒的测定。文中还就氧化剂的性质对分析灵敏度的影响及温度对测定线性范围的影响作了初步探讨。