摘要:

Chemiluminescence sensors are important tools in analytical chemistry due to their high sensitivity selectivity. This review presents the instrumentation involved in their design, including light detection and flow injection analysis system used. Various applications for the analysis of inorganic and organic compounds from gaseous samples and solutions indicate that these sensors are used with good reproducibility and selectivity of the analytes at low concentration level.

ISSN:1040-8347    

DOI:10.1080/10408340008984161

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The development of optical sensing approaches for analytes of biological, industrial, or environmental concern has reached an enormous significance. Different natural systems such as enzymes or antibodies have been employed in the development of these kind of sensors, but they often lack of stability. Molecular imprinting has become a universal tool for preparation of artificial and robust recognition materials mimicking natural systems. Molecular imprinting polymers (MIPs) are easily obtained by copolymerization of suitable functional monomers and crosslinkers in the presence of the target molecule. These polymers exhibit a tremendous thermal, chemical, and mechanical stability besides having selectivity similar to that of natural systems. Here we report an overview of molecular imprinting technique focussed to its sensing applications, emphasizing those systems based on an optical transduction.

ISSN:1040-8347    

DOI:10.1080/10408340008984162

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

In 1997, low-level perchlorate contamination (<50 ng mL−1or parts per billion) was discovered in the western U.S. Since that time, it has been found in sites scattered around the nation. Although the Environmental Protection Agency has not established a regulation for perchlorate in drinking water, it has placed perchlorate on the contaminant candidate list (CCL) and the unregulated contaminants monitoring rule (UCMR). A provisional and unenforceable concentration of 18 ng mL−1will stand until at least late 2000 when EPA hopes to issue a revised toxicological assessment. However, the need for techniques and methods for determining perchlorate is not constrained to environmental chemistry. Perchlorate salts are used pharmaceutically in Europe to treat Graves' disease and amiodarone-induced thyrotoxicosis. Ammonium perchlorate is used as a solid oxidant in space shuttles and intercontinental ballistic missiles. Thus, methods and techniques are necessary for quality control and quality assurance. Moreover, analysis of explosives and post-explosion residues have made quantitation of perchlorate important in forensic chemistry. A variety of techniques is available: gravimetry, spectrophotometry, electrochemistry, ion chromatography, capillary electrophoresis, mass spectrometry—each has its strengths and weaknesses. Within each technique, assorted methods are available with corresponding limits of detection. As the breadth of matrices undergoing analysis expands from potable water to agricultural runoff, fertilizers, fruit juices, or physiological and botanical fluids, the risk for interference becomes greater. As toxicologists demand lower and lower limits of detection, it falls to analytical chemists to ensure selectivity and sensitivity go hand-in-hand. In the near future, we can expect refinements in sample pretreatment and clean-up as well as analytical methods geared toward analyzing more complex matrices. Ion chromatography, capillary electrophoresis, Raman spectrometry, and electrospray ionization mass spectrometry will all play roles in environmental analysis; however, IC should be expected to dominate drinking water analysis. This review describes the state of the science and how it might be applied, and looks forward to where it is going and how it might get there.*Note: This paper is an original U.S. government work and is not subject to copyright.

ISSN:1040-8347    

DOI:10.1080/10408340008984163

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

A systematic approach to qualitative analysis at the down of the twenty-first century is presented. After a description of the most salient features of the binary yes/no response (types, quantitative connotations, properties and errors), the main types of qualitative analysis and the role played by standards and calibration are discussed. An overview of qualitative procedures based on classic and instrumental tools is provided. The significance of sample and analyte screening systems used to obtain binary responses is also discussed. Finally, the main present challenges of qualitative analysis are outlined.

ISSN:1040-8347    

DOI:10.1080/10408340008984164

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor