Abstracts

• Published in: Analytical letters Vol. 37; no. 14; pp. v - xiii
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 30.12.2004
• ISSN: 0003-2719; 1532-236X
• DOI: 10.1081/AL-200036522

DETERMINATION OF METALS IN CRUDE OIL BY ATOMIC SPECTROSCOPY by Carey Hardaway and Joseph Sneddon, Department of Chemistry, McNeese State University, Lake Charles, Louisiana, USA; James N. Beck, Department of Physical Sciences, Nicholls State University, Thibodaux, Louisiana, USA ABSTRACT: Following an introduction to the origin and concentration of metals in crude oils, a brief overview of the major atomic spectroscopic methods, i.e., inductively coupled plasma-atomic emission spectrometry, inductively coupled plasma-mass spectrometry, and flame and graphite furnace atomic absorption spectrometry, and an overview of sample preparation/sample introduction are presented. Results are presented of a number of studies with V and Ni being the most widely determined metals in crude oil. Analytical Letters, 37(14), 2881-2899, 2004 ELECTROCHEMICAL DETECTION OF PROTEIN USING A DOUBLE APTAMER SANDWICH by Kazunori Ikebukuro, Chiharu Kiyohara, and Koji Sode, Tokyo University of Agriculture and Technology, Nakamachi, Koganei, Tokyo, Japan ABSTRACT: We have developed an electrochemical sensor system for protein detection using two different antithrombin aptamers that recognize different parts of the target protein. In this case, thrombin was detected using a sandwich format comprised of a glucose dehydrogenase (GDH)-labeled antithrombin aptamer and another aptamer that was immobilized onto the gold electrode for capturing the thrombin onto it. The electric current generated by the GDH when glucose was added was measured, and 1 µM of thrombin was detected selectively. Analytical Letters, 37(14), 2901-2909, 2004 ELECTROCHEMISTRY OF HEMOGLOBIN ON A GOLD COLLOID-1,4-BENZENEDIMETHANETHIOL MODIFIED ELECTRODE AND ELECTROCATALYTE DETECTION OF HYDROGEN PEROXIDE by Bin Fang, Guangfeng Wang, Xiaohong Yang, Qingqing Zha, Wenzhi Zhang, and Xianwen Kan, College of Chemistry and Material Science, Anhui Normal University, Wuhu, P.R. China ABSTRACT: Hemoglobin (Hb) was successfully immobilized on gold nanoparticles (GNP) associated with a 1,4-benzenedimethanethiol (BDT) monolayer on a gold electrode surface and was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Direct electron transfer (DET) between Hb and the modified electrode was achieved without the aid of any electron mediator. GNP can greatly promote the redox of Hb, on which a pair of obvious CV peaks for Hb Fe(III)/Fe(II) redox couple were obtained in pH 6.2 phosphate buffer solution (PBS). In pH 6.2 PBS, the formal potential (E°') of Hb was −0.180 V (vs. SCE), and the electron transfer rate constant was 5.2 s −1 . The formal potential of Hb on gold colloidal modified electrode shifts linearly with pH with a slope of −55.5 mV/pH at 20°C, showing that the electron transfer is accompanied by single proton transportation. The high efficiency of the Hb/GNP/BDT modified gold electrode toward the catalytic electroreduction of hydrogen peroxide has been observed. The immobilized Hb gave an excellent electrocatalytic response to H 2 O 2 . Potential application of Hb/GNP/BDT modified gold electrode as biosensors to monitor H 2 O 2 is proposed. Analytical Letters, 37(14), 2911-2924, 2004 DETECTION OF ZINC AND LEAD IN WINE BY POTENTIOMETRIC STRIPPING ON NOVEL DENTAL AMALGAM ELECTRODES by Øyvind Mikkelsen, Camilla Nordhei, Silje M. Skogvold, and Knut H. Schrøder, Department of Chemistry, Norwegian University of Science and Technology, Trondheim, Norway ABSTRACT: A simple method for detection of zinc and lead in wine by use of potentiometric stripping analyses (PSA) on the dental amalgam electrode is introduced and demonstrated for 10 different wines, both red and white. The combination of PSA and the novel nontoxic electrode offers a fast and easy-to-use technique without matrix effects seen in, e.g., voltammetry. Concentrations of zinc in the range of approximately 2.1 × 10 −6  M to 11.7 × 10 −6  M (3.5% std. dev.) and lead in the range of 9.7 × 10 −8  M to 2.4 × 10 −7  M (3.5% std. dev.) were found in the actual wine samples. PSA measurements were verified against atomic adsorption spectroscopy analyses (AAS), and a good correlation factor was found (r 2  = 0.96). A simple speciation study was performed by measuring the amount of zinc and lead before and after the addition of acid, giving an approximate ratio between free and total amount of the metals. Estimated detection limits for zinc and lead were calculated to, respectively, 3.0 × 10 −7  M and 1.5 × 10 −8  M for 120 sec. of plating time. Analytical Letters, 37(14), 2925-2936, 2004 SYNTHESIS OF A NEW WATER-SOLUBLE POLYMERIC PROBE AND ITS FLUORESCENT PROPERTIES FOR RATIOMETRIC MEASUREMENT OF NEAR-NEUTRAL pH by Suying Dong, Huimin Ma, Xiaohua Li, Ming Sun, and Xuejun Duan, Laboratory of Chemical Biology, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China ABSTRACT: A new water-soluble polymeric fluorescent probe, poly[allylamine-co-N-4-chloro-6-(4-methylcoumarin-7-oxy)-1,3,5-triazinylallylamine] (PA-TMC), has been designed and characterized for near neutral pH measurement in dual-excitation ratio application. The probe was synthesized by using cyanuric chloride as a linker, 7-hydroxy-4-methylcoumarin as a fluorophore, and polyallylamine as a water-soluble molecular scaffold. It showed a large pH-dependent shift of excitation peak from 320-360 nm with no change of emission wavelength of 448 nm. The pK a value of the probe was 7.56, and the ratio R (I 360 /I 320 ) of fluorescence intensities at the two excitation wavelengths of 360 nm and 320 nm was directly proportional to pH values over the range 6.8-8.5, which may be suitable for the pH monitoring of near-neutral systems. Spectroscopic properties of the probe were also compared to the corresponding low molecular weight 7-(4,6-dichloro-1,3,5-triazinoxy)-4-methyl-coumarin (TMC). The results showed that the incorporation of TMC into a water-soluble polymer bearing a large number of hard base ligands offers both considerably improved selectivity for H + and solubility in water, suggesting that such a measure may be useful for preparing other probes with special functions. Analytical Letters, 37(14), 2937-2948, 2004 SPECTROPHOTOMETRIC DETERMINATION OF PEROXYNITRITE USING O-PHENYLENEDIAMINE AS A PROBE by De-Jia Li, Li-Lin Wang, Xuan Zeng, and Guo-Lin Zou, College of Life Sciences, Wuhan University, Wuhan, Hubei, P.R. China ABSTRACT: In the present study, a novel spectrophotometric method for the determination of peroxynitrite using, o-phenylenediamine as a probe is described. The method is based on the oxidation of o-phenylenediamine, a colorless substance, by peroxynitrite to give a colored product. The absorbance increase of the reaction system is linearly related to the concentration of peroxynitrite in the range of 4.4 × 10 −7 -8.0 × 10 −6  mol l −1 with a detection limit of 1.7 × 10 −7  mol l −1 (3σ). The optimal conditions for the detection of peroxynitrite were evaluated and the possible detection mechanism was also discussed in this paper. Analytical Letters, 37(14), 2949-2963, 2004 ELEVATED FIBRINOGEN-FIBRIN DEGRADATION PRODUCTS (FDP) IN SERUM OF COLORECTAL CANCER PATIENTS by Perry Rucker, Seashore Tetrachem, Inc., Santa Ana, CA, 92705, USA; Sheila M. Antonio, AMDL Inc., Tustin, CA, USA; and Barbara Braden, Medical Dept II, Johann Wolfgang Goethe University, Frankfurt/Main, Germany ABSTRACT: Serum fibrinogen-fibrin degradation product (FDP) levels of healthy control subjects and of patients with colorectal cancer have been measured by DR-70 ® ELISA in Frankfurt, Germany (Germany study) and in Tustin, California (U.S. study). Serum FDP levels of patients with colorectal cancer were significantly higher than those of the healthy controls. The median serum FDP levels in healthy control groups of the German and U.S. studies were, respectively, 0.37 µg/mL and 0.61 µg/mL. The median serum FDP levels in the colorectal cancer groups of the German and U.S. studies were, respectively, 1.25 µg/mL and 1.60 µg/mL. The results are consistent with enhanced fibrinolysis in serum of patients with colorectal cancer. Analytical Letters, 37(14), 2965-2976, 2004 DETERMINATION OF PAPAVERINE BY BIOTIN-AVIDIN AMPLIFIED ELISA by Jin Yan, Jing Wang, Mei-Ping Zhao, and Wen-Bao Chang, The Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, P.R. China ABSTRACT: Papaverine [1-(3,4-dimethoxybenzyl)-6,7-dimethoxyisoquinoline; PAP] is one of the most important alkaloids among the naturally occurring opium alkaloids. This work developed an indirect competitive enzyme-linked immunosorbent assay (ELISA) for PAP based on the biotin-avidin amplification system. The linear range of the calibration curve and the limit of detection (defined as three times of the blank) were 0.02-1000 ng/mL and 0.008 ng/mL, respectively. The established method was successfully applied to determining the concentration of PAP in the pericarpium papaveris with the recoveries between 88% and 120%. It was proved to be a highly sensitive and practical method for trace PAP detection compared with the existing gas chromatography-mass spectrometry (GC-MS) or high-performance liquid chromatography (HPLC) methods. Analytical Letters, 37(14), 2977-2989, 2004 DETERMINATION OF HUMAN IgG BY SOLID SUBSTRATE-ROOM TEMPERATURE PHOSPHORESCENCE IMMUNOASSAY by Jia-Ming Liu, Huan-Huan Xu, Ping-Ping Li, and Bi-Hua Chen, Department of Chemistry, Zhangzhou Normal College, Zhangzhou, P.R. China; Long-Di Li, Department of Chemistry, Tsinghua University, Beijing, P.R. China; and Jian-Ping Gao, Zhangzhou Chinese Medical Hospital, Zhangzhou, P.R. China ABSTRACT: Silicon dioxide nanoparticle containing fluorescein isothiocyanate (FITC-SiO 2 ) with the particle size of 20 nm was synthesized by solgel method. It can emit strong and stable solid substrate-room temperature phosphorescence (SS-RTP) signal on the substrate of polyami