Showing papers in "Critical Reviews in Analytical Chemistry in 1999"
TL;DR: Green Chemistry has emerged in the 1990s as a way that the skills, knowledge, and talents of chemists can be used avoid threats to human health and the environment in all types of chemical processes as discussed by the authors.
Abstract: Green Chemistry has emerged in the 1990s as a way that the skills, knowledge, and talents of chemists can be used avoid threats to human health and the environment in all types of chemical processes. One of the most active areas of Green Chemistry research and development is in analytical methodology development. New methods and techniques that reduce and eliminate the use and generation of hazardous substances through all aspects of the chemical analysis lifecycle are the manifestations of the recent interest in Green Analytical Chemistry.
390 citations
TL;DR: In this article, a review of cellulose sorbents for solid phase extraction is presented based on 42 literature references and shows favorable properties for this purpose, depending on the functional groups attached, the sorbent can be directly used for sorption or can be loaded with ligands specifically binding certain species.
Abstract: Regardless the progress in detectability of various instrumentation for trace metal determination, the preconcentration steps are very often needed for the analysis of environmental samples. Among the different techniques that can be used for this purpose, solid-phase extraction using various sorbents has been developed very intensively in recent years. Besides preconcentration, it can also be used for matrix removal necessary in some procedures or for the speciation of trace elements. This review is based on 42 literature references and shows favorable properties of cellulose sorbents for this purpose. Depending on the functional groups attached, the sorbent can be directly used for sorption of target analytes or can be loaded with ligands specifically binding certain species. Applications are reviewed for conventional batch procedures, flow-injection sample processing, and speciation of certain trace elements.
197 citations
TL;DR: The sol-gel process provides a versatile method to prepare size, shape, and charge selective materials for chemical analysis as discussed by the authors, which can be used to preconcentrate an appropriately charged analyte into a film for detection.
Abstract: The sol-gel process provides a versatile method to prepare size, shape, and charge selective materials for chemical analysis. Ion-exchange sites or functionalities can be introduced into the inorganic framework as a means to preconcentrate an appropriately charged analyte into a film for detection. Template-based approaches can be utilized to design porous inorganic hosts with improved molecular recognition capabilities. Chromatographic stationary phases with excellent thermal and hydrolytic stability can be designed to separate complex mixtures. Through variations in the sol-gel processing conditions (silicon-to-water ratio, pH, type of silicon alkoxide), membranes with optimal porosity and/or hydrophobicity can be prepared for gas separation and facilitated transport applications. In this review some of the unique features and new applications of sol-gel technology are described as it pertains to the development of materials with improved molecular specificity for chemical analysis.
129 citations
TL;DR: In this article, the state of the art in sample preparation, particularly in the area of supercritical fluid extraction, microwave-assisted extraction, accelerated-solvent extraction for solid matrices, and both solid-phase extraction and solid phase microextraction for aqueous matrices.
Abstract: Sample preparation continues to be an important step in environmental analysis and a lot of progress has been made in the last decade toward the development of faster, safer, and more environmentally friendly techniques for sample extraction and extract clean up prior to instrumental analysis. This article focuses on the state of the art in sample preparation, particularly in the area of supercritical fluid extraction, microwave-assisted extraction, accelerated-solvent extraction for solid matrices, and both solid-phase extraction and solid phase microextraction for aqueous matrices. Driven by the need for faster, cheaper, and more sensitive analytical methods, advances in sample preparation have included not only automation but many developments in coupling sample preparation with instrumental analysis (e.g., supercritical fluid extraction coupled with immunoassays). Examples are presented for extraction of polynuclear aromatic hydrocarbons, organochlorine pesticides, polychlo-rinated biphenyls, phenolic...
78 citations
TL;DR: The most reliable mathematical models for data processing are presented and different types of electrochemical sensor arrays in analytical chemistry as well as their performances are shown.
Abstract: The importance of sensor arrays in environmental, food and clinical analysis is discussed. The possible designs of sensor arrays is shown. The most reliable mathematical models for data processing are presented. The importance of different types of electrochemical sensor arrays in analytical chemistry as well as their performances are shown.
49 citations
TL;DR: In this paper, the data are first decomposed into principal components, and the number of contributing species is determined by statistical tests, then the principal components are rotated to produce spectroscopic responses and concentration profiles of the chemical species present.
Abstract: Chemometric methods to analyze spectroscopic data without using reference spectra are discussed. The data are first decomposed into principal components, and the number of contributing species is determined by statistical tests. The principal components are then rotated to produce spectroscopic responses and concentration profiles of the chemical species present. Samples that vary in a physical property like pH, total concentration, temperature, or ionic strength, are analyzed by regular 1-dimensional spectroscopy assuming that the components are in chemical equilibrium. Samples containing noninteracting compounds are analyzed by multidimensional spectroscopy, and the principal components are calculated by Procrustes rotation. Several applications of the two approaches on absorption and fluorescence data are presented.
40 citations
TL;DR: The use of agricultural biopolymers that are easily biodegradable not only would solve these problems but would also provide a potential new use for surplus farm production.
Abstract: Synthetic, petroleum-based polymer films are extremely stable and are commonly used in agriculture, food packaging, fast-food restaurants, and on military and commercial ships. However, their attractive stability is counterbalanced by two problems. One is that petroleum polymers contribute to the demand for expensive imported oil. The other is their great resistance to biodegradation. When disposed they constitute a serious problem with very negative environmental impact. For example, the most frequently used polyethylene film takes 200 years to biodegrade. On the other hand, the use of agricultural biopolymers that are easily biodegradable not only would solve these problems but would also provide a potential new use for surplus farm production. Unfortunately, films from agricultural polymers are initially inferior to synthetic polymers mostly because of their difficult moldability and poorer physicochemical properties. However, specifically modified acidic carbohydrates and proteins with disulfide bondi...
28 citations
TL;DR: In this paper, the advances in the design of chemiluminescence-based sensors and biosensors with particular emphasis on their classification are discussed and several up-to-date applications are presented.
Abstract: This review discusses the advances in the design of chemiluminescence-based sensors and biosensors with particular emphasis on their classification. Several up-to-date applications are presented.
25 citations
TL;DR: In this article, the authors describe some possible designs of CE nonconventional samplers and discuss applications of such sampler in sample preparation, in coupling CE with flow injection analysis (FIA) and HPLC, in multiple input experiments (with or without stacking) for reduction of detection limits and for monitoring of reaction kinetics.
Abstract: Developments in nonconventional sample introduction in capillary electrophore- sis have focused on the possibility of forcing the sample stream to pass the separation capillary inlet. The advantages of such input devices are the absence of a voltage rise/drop time during sampling, ease of operation because no vial manipulations are involved, and ease of automation and computerization. However, besides these the main advantage of such input devices seems to be the fact that they facilitate easy, multiple input from a single sample vial. This opens the possibility of monitoring the concentration changes taking part in inside the vessel — an important task for — analytical biotechnology. This article describes some possible designs of CE nonconventional samplers and discusses applications of such samplers in sample preparation, in coupling CE with flow injection analysis (FIA) and HPLC, in multiple input experiments (with or without stacking) for reduction of detection limits and for monitoring of reaction kinetics.
18 citations
TL;DR: The role of electrochemistry in elucidation of genotoxic and ecotoxic properties, mechanism of their action, metabolism, fate in the environment, etc. is briefly discussed in this article.
Abstract: The polarographic and voltammetric behavior of chemical carcinogens is reviewed and the possible role of electrochemistry in elucidation of their genotoxic and ecotoxic properties, mechanism of their action, metabolism, fate in the environment, etc. is briefly discussed. The use of modern electroanalytical techniques, namely, differential pulse polarography, differential pulse voltammetry, adsorptive stripping voltammetry and high-performance liquid chromatography with electrochemical detection for the determination of trace amounts of these substances is described.
17 citations
TL;DR: In this article, a need to evaluate just the concentration of true humic substances, rather than summary parameters, characterizing dissolved organic substances such as COD, DOC, TOC, and others is stressed.
Abstract: Methods designed for analysis of aquatic humic substances are summarized and compared. A need to evaluate just the concentration of true humic substances, rather than summary parameters, characterizing dissolved organic substances such as COD, DOC, TOC, and others is stressed. Possible future trends in the studies of dissolved humic substances are touched on.
TL;DR: In this article, heavy metal ions concentration in the samples were quantified by Atomic Absorption Spectrometry and by Inductively Coupled Plasma Atomic Emission Spectrometer.
Abstract: The Arges River arises from the ice lake Capra, which is situated in the Fagaras mountains, and is flows into the Danube River near Oltenita city. During this “trip” it collects, more or less cleaned, industrial or home-originated wastewater and other waste materials. Some of these are deposited on the river bed, others are transported downstream by water or fish. Among antropogenic compounds, heavy metal ions may be the most harmful pollutants. While many other compounds are more or less biodegradable, heavy metal ions could be retained in the ecosystem, indefinitely. The water samples were collected between Cumpana and Oltenita from 12 sites placed in the middle of the stream. Heavy metal ions concentration in the samples were quantified by Atomic Absorption Spectrometry and by Inductively Coupled Plasma Atomic Emission Spectrometry. The values were compared with Anodic Stripping Voltammetry delivered results (Cu, Cd, Zn, Pb), which provided a good agreement. The values determined within our work repres...
TL;DR: In this article, the authors describe problems of organic substances that have persistent, bioaccumulative, and toxic characteristics likely to cause adverse human health or environmental effects, called PBTs.
Abstract: The article describes problems of organic substances that have persistent, bioaccumulative, and toxic characteristics likely to cause adverse human health or environmental effects. They are called PBTs (Persistent, Bioaccumulative, Toxic substances) and briefly the state of the PBTs problems in the countries of Central and Eastern Europe is described. As an example of research activities in the region, the long-term research program of Czech and other scientists so-called Project TOCOEN (Toxic Organic COmpounds in the ENviron-ment) is described.
TL;DR: The performance-based measurement system (PBMS) as discussed by the authors was proposed by the U.S. Environmental Protection Agency (EPA) to encourage analytical innovation by allowing the use of new and alternate methods provided that predetermined performance criteria are met.
Abstract: The mission of the United States Environmental Protection Agency (EPA) is to protect human health and safeguard the natural environment. EPA was established to implement and enforce environmental regulations passed by the U.S. Congress to control pollutants discharged into the air, water, and land. To implement these regulations, EPA develops test procedures (analytical methods) to measure regulated pollutants. These methods are contained in regulations codified at Title 40 of the U.S. Code of Federal Regulations (40 CFR). Nearly all of the current test procedures are prescriptive, meaning that they contain exacting procedures for performing tests. Recently, EPA has initiated an effort to implement a performance-based measurement system (PBMS) that will introduce flexibility in conducting environmental monitoring. This initiative will encourage analytical innovation by allowing the use of new and alternate methods provided that predetermined performance criteria are met. This article presents an overview ...
TL;DR: It is argued that the value of any analysis, new chemical sensor, or a new analytical procedure for environmental management task is ultimately determined by its rational use.
Abstract: Obtaining new information through characterizaton (chemical analysis) has its costs associated with it. These costs must be justified. It is argued that the value of any analysis, new chemical sensor, or a new analytical procedure for environmental management task is ultimately determined by its rational use. A formal procedure for justification of chemical characterization is outlined.