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Current Analytical Chemistry
ISSN: 1573-4110
Current Analytical Chemistry
Volume 2, Number 3, July 2006
Contents
Comparison Between Voltammetric and Spectrophotometric
Methods for Drug Analysis Pp. 229-241
Luigi Campanella, Adriano Ambrosi, Francesco Bellanti and
Mauro Tomassetti
[Abstract]
New Methods of Affinity Electrophoresis Pp.
243-251
Bao-Shiang Lee, Sangeeth Krishnanchettiar, Syed S. Lateef
and Shalini Gupta
[Abstract]
Rapid Determination of Levofloxacin at Nanogram
Level in Pharmaceuticals and Biological Fluids Using Flow
Injection Chemiluminescence Pp. 253-259
Xiaodong Shao, Xiaofeng Xie, Yanhong Liu and Zhenghua
Song
[Abstract]
Guanine-Quadruplexes Studied by Fluorescence Techniques
Pp. 261-270
Bernard Juskowiak
[Abstract]
X-Ray Fluorescence Analysis of Valuable Metals
Pp. 271-277
Alicia Jurado-López and Maria D. Luque de Castro
[Abstract]
Layer-by-Layer Assembly Films and their Applications
in Electroanalytical Chemistry Pp. 279-296
Longzhen Zheng, Xin Yao and Jinghong Li
[Abstract]
Microcantilever (MCL) Biosensing Pp.
297-307
Xiaodong Yan, Hai-Feng Ji and Thomas Thundat
[Abstract]
A Profile of Current Methods for DNA Methylation
Analysis Pp. 309-322
Peng Hou, Meiju Ji, Zaozao Chen and Zuhong Lu
[Abstract]
Biochips for Detection of DNA Mutations
Pp. 323-330
Li-Jun Bi, Xian-En Zhang, Ya-Feng Zhou and Jiao-Yu Deng
[Abstract]
Methodology and Application of the Derivative
Atomic Absorption Spectrometry Pp. 331-339
Han-wen Sun and Li-qing Li
[Abstract]
Abstracts
[Back to top]
Comparison Between Voltammetric and Spectrophotometric
Methods for Drug Analysis
Luigi Campanella, Adriano Ambrosi, Francesco Bellanti and
Mauro Tomassetti
The possibility of determining the content of various
active pharmaceutical principles (Carbamazepine, Diclofenac,
Ofloxacin, Sulfamethoxazol, Clofibric acid and Propranolol)
in water and in commercial formulation by Voltammetric-Polarographic
methods has been investigated. The considered pharmaceutical
principles are the ones selected by the Rempharmawater European
Union Program, as belonging to the class of the most used
in Europe and six commercial drugs have been considered.
The obtained data were compared with the results by UV spectrophotometry.
[Back to top]
New Methods of Affinity Electrophoresis
Bao-Shiang Lee, Sangeeth Krishnanchettiar, Syed S. Lateef
and Shalini Gupta
Several alternative methods of conducting affinity electrophoresis
are described, including countercurrent affinity electrophoresis,
antibody affinity electrophoresis, functional affinity electrophoresis,
and avidin functional affinity electrophoresis. The basis
of these new techniques is to catch the prey molecules while
they migrate electrophoretically through the immobilized bait
molecules region of the polyacrylamide gel. Potential applications
of these techniques will be indicated.
[Back to top]
Rapid Determination of Levofloxacin at Nanogram Level in Pharmaceuticals
and Biological Fluids Using Flow Injection Chemiluminescence
Xiaodong Shao, Xiaofeng Xie, Yanhong Liu and Zhenghua
Song
A new flow injection method for the determination of levofloxacin
based on the enhancement of the intensity of chemiluminescence
(CL) from the luminol-KIO4
system was described in this paper. The enhanced chemiluminescence
intensity was linear with the concentration of levofloxacin
over the range from 7 ng mL-1 to 1000 ng mL-1
(r2=0.9991) with a detection limit (3σ)
of 2 ng mL-1. At a flow rate of 2.0 mL min-1,
a complete analytical process could be performed within 0.5
minute, with a relative standard deviation of less than 3.0%
(n=5). The recovery for the levofloxacin samples was from
91.0% to 109.4%. The proposed method was applied successfully
in the determination of levofloxacin in tablets, eyedrop,
human serum and urine samples.
[Back to top]
Guanine-Quadruplexes Studied by Fluorescence Techniques
Bernard Juskowiak
The study of telomeric DNA has acquired importance through
the discovery of the relationship between telomerase activity
in most cancer cells and telomere folding into tetraplex structure
(guanine-quadruplex). G-quadruplexes exhibit four-stranded
structure containing one or more nucleic acid strands with
a central channel able to accommodate metal cations. Coordination
of certain metal cations stabilizes G-quadruplex as do some
promising small organic molecules. Among many techniques employed
to explore properties of G-quadruplexes, fluorescence spectroscopy
has been recognized as a powerful tool due to high sensitivity
and multidimensionality. Information about concentration,
molecular structure, binding events, and motion can be obtained
using fluorescence methods, e.g., the fluorescence resonance
energy transfer (FRET) technique.
This review will show how fluorescence spectroscopy contributes
to G-quadruplex research and will focuse on the FRET application,
describing briefly also the underlying principles. Review
will summarize the current developments in the field of the
various applications of fluorescent measurements for both
the fundamental structural investigations of G-quadruplexes
and their complexes with organic ligands as well as some practical
applications. Applications include fluorescence and FRET-based
selection of efficient quadruplex-binding ligands and metal
cations, design of molecular probes for protein recognition
and development of sensors for detection of potassium ions
in aqueous solution.
[Back to top]
X-Ray Fluorescence Analysis of Valuable Metals
Alicia Jurado-López and Maria D. Luque de Castro
This paper reviews the use of X-ray fluorescence spectrometry
(XRFS) for non-destructive studies of valuable metallic objects
in the fields of jewelry, archaeology and art, as well as
its application in the analysis of coatings and solutions,
due to the interest of these issues in jewelry manufacture.
The general features of the technique as well as the most
outstanding results obtained in the commented fields are described,
taking into account the most important sources of error, mainly
in the case of samples that have suffered corrosion processes.
[Back to top]
Layer-by-Layer Assembly Films and their Applications
in Electroanalytical Chemistry
Longzhen Zheng, Xin Yao and Jinghong Li
The layer-by-layer assembly technique is a rich, versatile,
and significantly inexpensive approach to the formation of
thin films via alternating adsorption of positively
and negatively charged species from aqueous solutions. Polymer
organic and organic/inorganic thin films formed using this
technique may contain a number of different functional groups,
including electro-optic, electrochromics, conducting, dielectric
layers with or without redox pairs, and functional organic
and inorganic nanoparticles. Ease of preparation, accurate
control over film thickness as well as flexibility in the
choice of constituents makes this technique very promising
for electroanalytical chemistry. Many applications have been
founded for the LBL assembled films, such as electrocatalysis,
direct electrochemistry, biosensor, electrochromics, selective
permeation, biofuel cell, and other analysis. Newly development
based on the alternating layer methods in electroanalytical
chemistry should be addressed.
[Back to top]
Microcantilever (MCL) Biosensing
Xiaodong Yan, Hai-Feng Ji and Thomas Thundat
The analytical community continues to search for cost-effective,
reliable, and even portable analytical techniques that can
give reliable and fast-response results for a variety of biochemicals.
Advances in the field of microelectro-mechanical systems (MEMS)
and their uses now offer unique opportunities in the design
of ultrasensitive analytical devices. Microcantilevers (MCLs)
have been emerged as a novel unique platform for label-free
biosensor or bioassay. This short review summarizes the biosensors
using microcantilever (MCL) technology. DNA-based, antibody-based,
enzyme-based, and membrane-based MCL sensors are discussed.
The review is intended to provide an experts in this field
an overview of MCL biosensors and to help the non-experts
in the field to acquire a good understanding of the development
of MCL biosensors and the main issues to be considered for
further development of this biosensor technique.
[Back to top]
A Profile of Current Methods for DNA Methylation
Analysis
Peng Hou, Meiju Ji, Zaozao Chen and Zuhong Lu
The methylation of DNA is an epigenetic modification that
can play an important role in the control of gene expression
in mammalian cells. The aberrant or accidental methylation
of CpG islands in the promoter region has been observed for
many cancer-related genes resulting in the silencing of their
expression. Hence, it has become a focus of scientific attraction
currently. Many of the early procedures developed gave only
somewhat limited information about methylation patterns, for
example, the overall levels of 5-methycytosine in the genome
or the frequency of methylation of cytosines within certain
restriction sites. However, in the last few years, there has
been an explosion of interest in DNA methylation, and with
it, many new and powerful techniques have been developed to
facilitate methylation analysis, especially the advent of
many high-throughput methods (e.g., restriction landmark genome
scanning, differential methylation hybridization, and DNA
microarray). In this paper, the key techniques currently available
are reviewed and the advantages and disadvantages are discussed.
This review will be valuable in selecting the best techniques
to address particular questions concerning methylation status
of genome DNA.
[Back to top]
Biochips for Detection of DNA Mutations
Li-Jun Bi, Xian-En Zhang, Ya-Feng Zhou and Jiao-Yu Deng
DNA mutation is the major cause of gene evolution. The variation
of DNA sequence may result in genetic diseases, genotypes,
single nucleotide polymorphism, and drug resistance of pathogens.
Using biochip technologies, detection of mutations can be
performed in parallel under identical conditions, hereby providing
a solution to continuously increasing demands for large-scale
genetic analysis. This article reviews the development of
the biochips for mutation analysis. Features, limitations
and applications of various principles are discussed.
[Back to top]
Methodology and Application of the Derivative Atomic
Absorption Spectrometry
Han-wen Sun and Li-qing Li
The mathematical models are established for conventional atomic
spectrometric signals by simulating experimental results with
computer. The laboratory-made derivative measurement system
is described. The mathematical models of derivative signals
are developed for flame atomic absorption spectrometry (FAAS),
cold vapour atomic absorption spectrometry (CVAAS), hydride
generation atomic absorption spectrometry(HGAAS) and flow
injection flame atomic absorption spectrometry (FIFAAS) and
gas chromatography atomic absorption spectrometry (GCAAS).
The intensity of derivative signal is in direct relation to
concentration of analyte with a good linearity. A theoretical
principle is developed for derivative-FAAS, derivative-FAES,
derivative-CVAAS, derivative-HGAAS derivative-FIFAAS, and
derivative-GCAAS. The performance and application of the derivative
atomic absorption spectrometry in trace element analysis are
reviewed.
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