bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organic Acids Analysis in Environmental Samples, Ion Chromatography for Determination of
Authors: Peldszus Sigrid 
Published: September 2006

Abstract
The analysis of environmental samples typically focuses on aliphatic short‐chain organic acids. The origin of these organic acids and the motivation for their analyses are unique for each type of matrix. Environmental sample matrices are very diverse and can range from air and atmospheric precipitation such as fog, rain or snow to wastewater, drinking water or landfill leachates and soil pore water. This diversity in matrix leads to substantial differences in organic acid concentrations and different organic acid distributions in the various types of environmental samples. Hence, the analytical techniques employed have to be adapted to the particular matrix under investigation.
Ion chromatography is one of the most commonly used techniques for organic acid analysis. Competing ion chromatographic methodologies are anion (ion)‐exchange chromatography (IC) and ion exclusion chromatography (ICE). The separation principles underlying each of these techniques are very different and may be used to their advantage. In IC, anions are separated by anion exchange processes between the cationic exchange groups on the resin and the eluent. Hence, inorganic anions and carboxylate anions may be analyzed at the same time (e.g. rain). Limitations of this technique set in when the inorganic anion concentration is much larger than the carboxylate concentration. As a consequence, inorganic anion peaks may mask or co‐elute with the analyte of interest. However, techniques have been developed to handle this problem, for example in drinking‐water analysis. The separation mechanism in ICE is much more complex than in IC involving Donnan exclusion, adsorption and steric exclusion. ICE is generally used for the separation of weak organic acids since strong organic acids elute in the system peak in the front of the chromatogram. Hence, large concentrations of strong inorganic anions, for example sulfate or chloride, will not interfere with the analysis of weak organic acids. However, organic acids with relatively low p Ka values may be difficult to separate from the system peak. In addition, weak inorganic acids such as carbonate have the potential to interfere with the analysis of certain organic acids if present in large enough concentrations.
Other techniques than ion chromatography have been used for organic acid analysis. Direct injections of samples into a gas chromatograph are very common for measuring volatile fatty acids (VFAs) in wastewater. More complex gas chromatography (GC) methods, which include concentration and derivatization steps, have been employed to analyze for specific types of organic acids such as dicarboxylic acids in rain. Capillary electrophoresis (CE) is a newer technique, which has not been used widely in routine analysis. However, speciality applications such as the determination of organic acids in a single raindrop show the potential of this type of methodology.
Organic Analysis in Environmental Samples by Capillary Electrophoresis
Authors: García‐Ruiz Carmen , Crego Antonio L. , Marina Maria L. 
Published: September 2006

AbstractCapillary electrophoresis (CE) is an instrumental technique that employs narrow‐bore (10–100 µm ID, internal diameter) capillaries under the influence of a high‐gradient electric field to perform high‐efficiency separations. Different working modes of CE have been described. Capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) have become the most popular modes of CE in environmental applications. Other kinds of electrokinetic chromatography (EKC) and other modes of CE like capillary electrochromatography (CEC) have also been used.CE techniques have been considered as a good alternative for analyzing pollutants because of their high performance and versatility related to selectivity and range of application. In addition, CE is a powerful tool in the field of chiral separations and it is considered one of the so‐calledcleananalytical techniques. Although the main drawback of CE techniques in environmental analysis is their insufficient sensitivity for detecting trace‐level pollutants, some procedures have been developed in order to overcome this problem.
Pervaporation, Analytical
Authors: Luque de Castro M.D. , Gámiz‐Gracia L. 
Published: September 2006

AbstractThe use of pervaporation in analytical chemistry is a relatively new development. Pervaporation is a separation technique for the removal of volatile analytes or their volatile derivatives from the sample matrix. It can be defined as the integration of evaporation and gas diffusion in a single module. The volatile substances present in a heated donor phase evaporate through a porous membrane and the vapor condenses on the surface of a cool acceptor stream on the other side of the membrane. The temperature difference across the membrane is the driving force for the separation. An important characteristic of analytical pervaporation is the presence of a constant‐volume air gap between the sample in the donor chamber and the membrane, which hinders any contact between them, thus avoiding clogging and/or deterioration of the membrane.Pervaporation can also be used for sample pretreatment, e.g. for solid samples where leaching and derivatization of the analytes are done simultaneously. In this article, the applications of analytical pervaporation that have been developed so far are discussed. Special attention is paid to its use as an alternative to gas diffusion, to liquid samples containing solids in suspension and/or corrosive, to solid samples in which a single analyte must be determined, to multideterminations, and to speciation studies. The integration of this separation technique with detection and the coupling of a pervaporator to a gas chromatograph (GC), which constitutes a valid alternative to headspace sampling, is also commented upon.
Phenols Analysis in Environmental Samples
Authors: Moeder Monika 
Published: September 2006

Abstract
Phenolic compounds are widely distributed in our ecosystems. In addition to naturally occurring phenols, the majority of toxic phenolic substances are released into the environment by industry and agriculture. As the manufacture and use of phenols requires qualitative and quantitative control, a wide variety of methods have been developed to determine phenolic compounds. In addition to coarse screening to rapidly obtain a general overview, many highly specialized techniques exist that are geared to individual analysis problems. The range of available methods extends from steam distillation and classic liquid–liquid extraction (LLE) as sample preparation combined with photometric or ultraviolet (UV) detection, to more sophisticated techniques such as liquid–solid extraction (LSE) including solid‐phase extraction (SPE) and solid‐phase microextraction (SPME) coupled to gas chromatography/mass spectrometry (GC/MS) and high‐performance liquid chromatography/mass spectrometry (HPLC/MS). This article describes the most suitable methods, taking account of special factors such as substance class, chemical properties, concentration range and accompanying matrices. Some new trends in phenol determination are also discussed in comparison with the established methods. The basic factors governing the selection of suitable analysis methods are also covered.
Polynuclear Aromatic Hydrocarbons Analysis in Environmental Samples
Authors: Fisher Michal , Schechter Israel 
Published: September 2006

AbstractThis chapter reviews conventional and novel methods of analysis of polynuclear aromatic hydrocarbons in environmental samples. Sampling and pretreatment techniques of air, soil and water are discussed, as well as various clean‐up and extraction methods. Most of the relevant polycyclic aromatic hydrocarbons (PAHs) separation techniques are reviewed. The principles and performance of the common PAH detection systems are presented. An introduction to novel analytical techniques, which will probably be introduced in the near future, is also provided.
Sample Preparation for Elemental Analysis of Biological Samples in the Environment
Authors: Subramanian Kunnath S. 
Published: September 2006

AbstractThis article focuses on biological sample preparation methods which are unique to each of the commonly used instrumental techniques used in trace element analysis. The biological samples covered are mainly of human and animal origin. The preparation methods considered span the entire gamut and include direct solid or liquid sample introduction involving dilution or matrix modification; dry ashing; wet oxidation including microwave digestion and high‐pressure ashing; deproteinization; and tissue solubilization. The instrumental techniques covered are flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectrometry (GFAAS), inductively coupled plasma atomic emission spectrometry (ICPAES), inductively coupled plasma mass spectrometry (ICPMS), X‐ray fluorescence (XRF) spectrometry, neutron activation analysis (NAA) and anodic stripping voltammetry (ASV). The choice of a given sample preparation method would be governed in general by the type of biological matrix, sample size and the type of instrumental technique used. The advantages and disadvantages of the various sample preparation methods have been emphasized for each of the instrumental techniques. Also, an attempt has been made to point out the optimum sample preparation method(s) suitable for the particular biological matrix and instrumental technique.
S
oxhlet and Ultrasonic Extraction of Organics in Solids
Authors: Webster G.R. Barrie 
Published: September 2006

Abstract
Soxhlet extraction is the removal and recovery of organic analytes from a permeable solid matrix by means of a solvent which is continually evaporated from a still‐pot and condensed in such a manner that it falls into and permeates through the matrix which itself is held in a permeable container in a siphonable chamber. Soxhlet extraction has been used for over 120 years (since 1879) and is commonly used as a benchmark for total extractable organic residues.
Ultrasonic extraction is the removal and recovery of organic analytes from a permeable solid matrix by means of a solvent which is energized by sound energy at frequencies in excess of those audible to the human ear. Energy may be introduced into the sample by means of an ultrasonic probe which is inserted into the sample or an ultrasonic bath into which the sample plus solvent is immersed. The ultrasonic energy may be strong enough to disrupt and pulverize the matrix, thus increasing the extractability of the analyte.
The operation of the Soxhlet extractor is intuitively easy to grasp. Extraction is viewed as being complete or close to complete.
Ultrasonic extraction is convenient and straightforward. Ultrasonic baths provide relatively reliable sources of extraction energy.
Soxhlet extraction is solvent intensive and requires laboratory facilities in which flammable and toxic solvents can be used safely. The glassware required is expensive and vulnerable to breakage. Cooling of the condenser of the Soxhlet apparatus requires a constant supply of cooling water. Residues are concentrated in the still‐pot and are thus vulnerable to thermal degradation. Only total residue can be extracted by Soxhlet extraction; little or no speciation is possible.
Ultrasonic extraction must be performed under conditions which protect the hearing of laboratory personnel. The ultrasonic generator may generate heat which may affect the extraction process. Ultrasonic probes become pitted when used for the extraction of abrasive matrices such as soil, thus changing the energy generated and affecting the extraction efficiency of the procedure. Ultrasonic baths provide less intense extraction energy. Extraction of total residue is the aim of ultrasonic extraction; little or no speciation is possible.
Sampling Considerations for Biomonitoring
Authors: Koeckritz Tim , Wappelhorst Olaf , Markert Bernd 
Published: September 2006

Abstract
This article looks at various factors involved in the first step in biomonitoring, namely the sampling process with special reference to heavy metal levels in living organisms and their interaction with terrestrial ecosystems. Because samples taken in the field naturally form the basis for the entire biomonitoring process, it is vitally important that the margin of error in this step is kept as low as absolutely possible. An important initial step is the decision about which organisms to use and where to gather them. It is important to consider factors such as chemical composition, relationship to the ecosystem involved and the number of individuals available, in addition to the abiotic and biotic factors which influence the amount of heavy metal the organism takes in from its environment, or its bioavailability (heavy metal accumulation is the practical example for biomonitoring used in this article).
How the samples are collected is as important as what is collected, and here various topics are covered, from choosing the most suitable organism(s), to deciding how many samples to take in order for them to be representative of the entire population at that site, to economic considerations. Although exact sampling methods vary according to the organisms involved and there are very few publications in this field, some basic guidelines are given to follow in any case, as well as references to the existing published guides.
Slurry Sampling Graphite Furnace Atomic Absorption Spectrometry in Environmental Analyses
Authors: Miller‐Ihli Nancy J. , Baker Scott A. 
Published: September 2006

AbstractSlurry sampling graphite furnace atomic absorption spectrometry (GFAAS) is a powerful tool for the determination of trace elements in environmental samples owing to its high sensitivity, instrumental simplicity, and relatively low cost. In this technique, discrete aliquots of the slurry or suspension are deposited in a graphite tube and then electrically heated to produce atomic vapors. The absorption of the atomic vapor is measured, typically with a hollow cathode lamp (HCL) or electrodeless discharge lamp (EDL), to determine the amount of analyte present in the sample. To ensure that a representative portion of the slurry is injected into the furnace, the slurry must be stabilized or mixed immediately prior to analysis. Slurry sampling GFAAS detection limits (DLs) are typically in the range of 10−2to 1 part per million (pg absolute DLs). Precision (0.5–5%) and accuracy are also good, provided that proper guidelines for slurry preparation and instrument operation are followed, and samples are sufficiently homogeneous. An additional benefit of the technique is that matrix interferences are typically small; in fact, aqueous calibration standards are routinely used in the analysis of slurry samples. A limitation of slurry sampling GFAAS is that it is primarily a single‐element technique, although continuum source and sequential atomic absorption spectrometry (AAS) systems have been developed. Furthermore, the linear range is typically less than two orders of magnitude unless alternative wavelengths, or some other means of reducing sensitivity (e.g. minigas flow during atomization), are used. In addition, some environmental samples have to be ground if the sample is not in the proper form or if the analyte is not homogeneously distributed. Care must be taken during the grinding process to avoid contamination of the sample or fractional distribution of the analyte.
Soil Sampling for the Characterization of Hazardous Waste Sites
Authors: Schumacher Brian A. , van Ee J. Jeffrey , Englund Evan J. 
Published: September 2006

AbstractThe planning for and collecting of samples at hazardous waste sites is nearly always the first step in any program that involves the analysis of real‐world soil samples. Knowledge of numerous different, yet related, topics, such as data quality objectives (DQO), sampling network design, quality assurance (QA)/quality control (QC), documentation, site characterization, sample collection, and sample handling and preparation, is essential to ensure the success of any program in obtaining accurate (non‐biased), precise, and representative soil samples. It is often quoted that during sample collection, 80% or more, for stable contaminants (e.g. heavy metals, polychlorinated biphenyls, polyaromatic hydrocarbons), ranging up to 99.9%, for less stable contaminants (e.g. volatile organic compounds (VOCs)), of the total measurement error associated with a sample occurs. Hence the goal of the program planner is to develop the most efficient sampling design that collects the desired samples while minimizing sample errors. If all of the aforementioned topics are not taken into account during the sample planning and collecting phases of the program, then no matter how good the analytical data may be, the data may lead to incorrect decisions with respect to the extent, distribution, and need for remediation of contaminants at a site.
Trace Organic Analysis by Gas Chromatography with Selective Detectors
Authors: Rosenberg Erwin 
Published: September 2006

AbstractSelective detectors for gas chromatography (GC) allow one to detect selectively after gas chromatographic separation analytes that either contain certain elements or carry functional groups for which the detector is particularly selective (element‐selective detectors). Spectroscopic detectors are a class of selective detectors which, in the ideal case, may even allow the identification of the analytes through acquisition of molecule‐specific spectra. Selective detectors often allow the detection, quantitation or identification of analytes even in the presence of complex matrices and may thus significantly improve the selectivity of an analytical method.
Waste Extraction Procedures
Authors: Simmons Barton P. 
Published: September 2006

Abstract
Waste extraction procedures (EPs) were developed to identify wastes which have a potential for groundwater or surface water contamination. Procedures are used for both organic and inorganic substances to comply with specific regulatory requirements, for example, to identify wastes which are subject to regulation as hazardous wastes. In the United States, the toxicity characteristic leaching procedure (TCLP) is the most widely used procedure. Volatile organics are extracted using a zero‐headspace extractor, while semivolatile organics and inorganic substances are extracted using a bottle extractor. Because the typical batch EP does not measure a fundamental property of a waste, the result is highly dependent on steps in the protocol, particularly the choice of extraction solution. Although batch extraction tests like the TCLP are the most common procedures, other procedures using multiple pHs and multiple liquid : solid ratios have been developed to overcome the limitations of batch tests.
Water Analysis: Organic Carbon Determinations
Authors: Mopper Kenneth , Qian Jianguo 
Published: September 2006

Abstract
The determination of total organic carbon and dissolved organic carbon (TOC and DOC) is one of the most important parameters in water quality and environmental analysis today. TOC is composed of particulate organic carbon, DOC and volatile organic carbon, (POC, DOC and VOC). In most waters, DOC is the dominant component of TOC. POC consists of living and nonliving organic particles and can occasionally become quantitatively important. POC, DOC and VOC are operationally defined by the methods used to separate them. POC and DOC are usually separated from each other by filtration, which can introduce errors due to contamination and filter clogging. Other major errors in TOC and DOC analyses are related to contamination and losses during sampling, sample storage and sample manipulation. In particular, removal of inorganic carbon by either acidification with sparging or by acidification with evaporation to dryness results in variable loss of VOC.

Commonly used TOC and DOC methods fall into two approaches: wet oxidation and high‐temperature combustion (HTC). In both approaches, organic matter is oxidized to CO
2
, which is then usually determined by nondispersive infrared (NDIR) absorbance. Two wet oxidation methods are in common use: wet chemical oxidation (WCO) and ultraviolet oxidation (UVO). In WCO, a strong chemical oxidant, usually persulfate, is added to the aqueous sample and the digestion is usually carried out batchwise in a reactor at an elevated temperature. In contrast, UVO digestion is commonly carried out in a quartz coil surrounding a mercury vapor lamp. Thus, UVO methods can be readily automated using flow‐injection systems. Two types of HTC methods are currently in use: dry combustion and direct aqueous injection. In dry combustion methods, the sample is acidified, dried and the residue is combusted at high temperature in a sealed tube, usually in the presence of a catalyst. This method is advantageous for the analysis of large samples. In direct aqueous injection HTC methods, samples are injected into a high‐temperature column (600–900°C), which usually contains a catalyst. In recent years, the latter method has become widely used for the analysis of seawater and other waters because it appears to have a greater oxidation efficiency and precision than most of the other methods, and it can be readily automated. However, automated HTC instruments have problems in the analysis of saline samples, in particular, salt deposits in the sample injection system, memory (or carry‐over) effects, and system blank evaluation. Recently, improvements in the HTC injection system and column design have addressed these problems.
X
‐Ray Fluorescence Spectroscopic Analysis of Liquid Environmental Samples
Authors: Russell Philip A. 
Published: September 2006

Abstract
X‐ray fluorescence (XRF) spectrometry is an instrumental technique used for multielement analysis. It is one of only three techniques available to the modern analyst, the others being mass spectrometry and optical emission spectroscopy, the latter usually being the inductively coupled plasma (ICP) variant. The determination of environmental sensitive elements in the range P–U in aqueous and/or organic matrices provides challenges to all multielement techniques. With recent improvements in instrumentation and methods design (simplified sample preparation compared with other techniques), XRF, in particular for highly contaminated liquid waste, is becoming the preferred technique. XRF is shown to give the most cost effective and best overall speed of analysis across a range of diverse matrix types. Potable drinking water to highly toxic industrial sludge/waste can be analyzed for either precise ultralow level (parts per billion) or screening purposes, respectively. Energy‐dispersive X‐ray fluorescence (EDXRF) has provided the best all‐round performance with the introduction of dedicated instruments and standard methods for the analysis of environmentally sensitive elements in all forms of liquid matrices.