bluuebunny/crossref_metadata_2025_split huggingface dataset:
Herbicide Residues in Biota, Analysis of
Authors: Headley J.V. , Dickson L.C. , Cessna A.J. 
Published: September 2006

AbstractCurrent extraction, derivatization and clean‐up techniques, and instrumental methods are reviewed for the analysis of herbicide residues in biota. Sampling procedures are shown to be an integral part of the methodology. Herbicide analysis is seldom based on analyte‐specific methods but is usually integrated into multiresidue methods (MRMs). Current methods generally utilize relatively small sample sizes and miniaturized apparatus to take advantage of advances in instrumental performance and detection of analytes. These methods reduce the amount of solvent used for sample preparation and help to minimize waste generation. As well as using less solvent, the resulting miniaturized methods tend to be generally cheaper, faster, and less labor‐intensive than conventional methods and, furthermore, they reduce analyst exposure to hazardous materials.Mass spectrometry (MS), interfaced with high‐resolution gas chromatography (GC), high‐performance liquid chromatography (HPLC) and capillary electrophoresis (CE), has become the detection method of choice for herbicide analysis. MS is well suited to the confirmation of target analytes and the tentative identification of unknown analytes. HPLC–mass spectrometers are becoming more widely available and less expensive. CE is a relatively new separation technique providing many advantages over traditional gas and liquid chromatography, including shorter analysis times and smaller injection volumes. There have been advances in the development of immunoassays primarily for the rapid screening for herbicide residues. These methods, once optimized, can facilitate high sample throughput at relatively low cost compared to conventional approaches. To date however, development has been limited to aqueous systems and little immunoassay work has been done for the direct determination of herbicides in biota.
High‐Performance Liquid Chromatography/Mass Spectrometry Methods in Pesticide Analysis
Authors: Cappiello Achille , Palma Pierangela 
Published: September 2006

AbstractIn this article, a detailed overview of the current high‐performance liquid chromatography/mass spectrometry (HPLC/MS) instrumentation, suitable for the determination of a large number of pesticides, is reported. Particular emphasis is given to the role of the mass spectrometric apparatus involved in each interfacing technique with several types of information regarding the ionization processes, analyzer principles and system configurations. The article gives an up‐to‐date picture of the current instrumentation that is available and readers will find only brief references to some important historical approaches that are no longer in use.
Phenyl‐ and Sulfonylurea Herbicides: Single Class, Multiresidue Analysis of
Authors: Trevisan Marco , Vischetti Costantino 
Published: September 2006

Abstract

A review of analytical methods for phenyl and sulfonylurea herbicides is reported. Extraction from environmental samples can be carried out using different techniques like liquid–liquid partition, solid‐phase extraction (SPE), microwave‐assisted solvent extraction, and so on. Both herbicide classes are analyzed mainly using high‐performance liquid chromatography (HPLC) coupled with a mass detector. Quantification limits are around the parts per billion level for many compounds. Multiresidue determination is easy for phenylurea compounds, but for sulfonylureas is limited by the different pK
a
values of the compounds.
Pesticides (New Generation) and Related Compounds, Analysis of
Authors: Picó Y. , Font G. , Moltó J.C. , Mañes J. 
Published: September 2006

AbstractMiscellaneous pesticides and related compounds include the compounds that can neither be included in the classical chemical category of pesticides nor classified by their class of action. They are a heterogeneous group of substances like macrocyclic lactones, chloronicotinyls, tetranortriterpenoids, ammonium quaternary salts, dinitroanilines, acetamides, oximes, triazoles and pyridine‐based molecules. Their common characteristic is that they are recently developed pesticides. Sample preparations in environmental matrices: air, water, soil, food and biological samples are described. Analytical techniques for characterizing these compounds include gas chromatography (GC), high‐performance liquid chromatography (HPLC), and a wide variety of other emerging techniques such as capillary electrophoresis (CE), supercritical fluid chromatography (SFC), voltammetric and immunoassay techniques. Here, those applied to the field of real samples are presented.
Soil and Sediments: Pesticides Content Sampling, Sample Preparation, and Preservation
Authors: Steinheimer T.R. 
Published: September 2006

AbstractFor pesticide residue determination, field sampling and analysis of agricultural soils and sediments requires the consideration of several seemingly interrelated factors. The mechanisms by which pesticides are adsorbed, absorbed, and desorbed from soils are not well understood for most families of chemicals or for most soils. In addition, soil properties are both spatially and temporally variable, so that the question of sampling methodology becomes important in order to insure that the samples taken are statistically representative of the larger population being examined. Thus, the investigator must weigh the attributes and limitations of each and then choose the best overall compromise among sample size and numbers, analyte specificity, and experimental designs. Following proper collection, the laboratory analyst must then choose among several options for selective extraction techniques for removal of the pesticide analytes of interest. For most applications, one of the following will be used: a classical approach employing a suitable solvent or cosolvent mixture in either a batch shake‐out or Soxhlet extraction apparatus. Other more recently developed options include the use of extractant solvents or cosolvent mixtures held under elevated pressures and temperatures (pressurized fluid extraction (PFE)) or pure substances amended with cosolvent modifiers and held above their respective critical points (CPs) (supercritical fluid extraction (SFE)). Another option is the use of ultrasonic energy (sonication) to facilitate extraction. Each of these approaches relies upon an input of sufficient kinetic energy from an externally applied source to the sample slurried with extractant. As the binding energies responsible for the retention of pesticides on soil are overcome, sorbed solutes are released into the solution phase. Studies which address pesticide fate issues often also require determination of soil metabolite and degradate compounds along with the registered parent chemical. For many families of insecticides and herbicides, these same extraction protocols can be used to quantitatively remove the major daughter compounds from soils without requiring an additional extraction step.
Pesticides in Water: Sampling, Sample Preparation, Preservation
Authors: Liška Igor 
Published: September 2006

AbstractContamination of water by pesticides is an important issue in many regions, posing problems in the environmental, water management and health sectors. To assess the extent of contamination of water, effective and properly designed analytical methods having sufficient sensitivity and accuracy are needed. However, no matter how excellent are the state‐of‐the‐art analytical instrumentation and techniques applied, the data on trace concentrations of pesticides provided by the analytical system will be useless unless sufficient attention is given to sampling and sample preparation.To collect a representative water sample for pesticide analysis, all sampling parameters must be selected properly. This refers predominantly to the selection of the appropriate sampling site, sampling technique and volume of the water sample. To prevent the sample matrix from any undesirable alterations during its transport from the sampling site to an analytical laboratory, physical (e.g. temperature, light intensity) and chemical/biochemical (e.g. pH, microbial growth) conditions must be under control, i.e. the sample must be preserved carefully. An efficient alternative to the transport of liquid water samples from the sampling point to the laboratory is on‐site sorption of analytes on a solid phase. This minimizes the weight of transported samples and increases the stability of analytes.The determination of trace concentrations of pesticides in water samples and the complexity of environmental matrices require the application of an efficient sample‐handling procedure prior to separation and detection of these analytes. At present, liquid–liquid extraction (LLE) and solid‐phase extraction (SPE) are the most frequently applied sample‐handling techniques in the determination of pesticides in water. LLE is a traditional method that is still widely used in standardized methods. The increasing popularity of SPE is a result of its versatility and effectiveness and SPE is also preferred owing to the lower health risks.The introduction of new sorbent materials, the development of automated sample‐handling systems allowing unattended operation and newly emerging sample‐handling techniques such as solid‐phase microextraction (SPME) and membrane separation methods guarantee that sample preparation in pesticide analysis will remain a fertile area of development in the future.
Mass Spectrometry, High‐Resolution, (Homolog)‐Type Analysis of Petroleum and Synfuel Distillates and Refinery Streams
Authors: Scheppele Stuart E. 
Published: September 2006

AbstractThe complex chemistry and chemical engineering of fossil fuel materials including petroleums, coal‐derived liquids, tar sands, shale oils, refinery streams and refined products can often be adequately simplified by expressing the composition of these materials in terms of group types. Group (chemical) types are series of homologous compounds that exhibit similar chemical properties and a regular gradation of physical properties. A homologous series of compounds, the members of which are termed homologs, contains compounds in which successive members exhibit the same difference in chemical formula with the homologous unit of present interest being CH2. Mass spectrometry (MS) is an ideal, extensively used technique in analyzing for chemical types in terms either of the total amounts of the various homologous series of compounds present in a sample or of the individual members (homologs) of the various series of homologous compounds present in a sample. The focus of this article is the fundamentals of homolog‐type analysis because analyses expressed in terms of the amounts of individual homologs rather then in terms of the total amounts of group types benefits the understanding/prediction of the effect of experimental conditions on feedstock production/transportation, product distributions in feedstock refining, end‐product quality and environmental impacts. A homolog‐type analysis also permits the determination/prediction of chemical/physical properties of a sample that can be expressed as a function of composition; examples being reaction rates, distillation curves and elemental analyses. The discussion of techniques for obtaining the “molecular ion mass spectra” required to produce homolog‐type analyses focuses on the use of all glass heated inlet systems (AGHIS) and direct probes for sample introduction, low‐voltage electrons for ion formation, and double focusing magnetic sector (DF) and Fourier transform ion cyclotron resonance (FTICR) mass analyzers to resolve isobaric ions.
Fuel Performance Specifications, Mid‐Infrared Analysis of
Authors: Mizaikoff Boris 
Published: September 2006

Abstract
The release of the Clean Air Act (CAA) Amendments of 1990 introduced reformulated gasoline legislation regulating the composition of fuels and particularly gasoline in order to improve the air quality by a significant reduction in vehicle exhaust emission levels. With the introduction of certain amounts of nonfuel oxygenates into fuel including various alcohols such as methanol, ethanol, t‐butanol and ethers like methyl tert‐butyl ether (MTBE), ethyl tert‐butyl ether (ETBE), tert‐amyl methyl ether (TAME) and diisopropyl ether (DIPE) a reduction of carbon monoxide (CO) and unburned hydrocarbon emissions is envisaged. Furthermore, a reduction in aromatic compounds and benzene is demanded providing a decreased release of volatile organic compounds (VOCs).
With the implementation of this program, the refining industry and their petrochemical laboratories have been forced to control accurately and to monitor continuously their gasoline blending processes. Furthermore, regulatory agencies are required to implement the use of portable analytical techniques in order to ensure the enforcement of such novel threshold values.
Besides the conventional techniques using separation‐based methods such as gas chromatography (GC), the mid‐infrared (MIR) spectral range has gained significant importance. Owing to the molecule specific absorption patterns of ethers, alcohols and aromatics, the distinct determination of fuel additives and subsequent derivation of general fuel parameters is enabled. The performance of FTIR (Fourier transform infrared) and filter‐based spectroscopic techniques will be reviewed and compared to other spectroscopic approaches. Furthermore, data evaluation procedures and ASTM (American Society for Testing and Materials) approval of these novel methods will be highlighted.
Fuels Analysis, Regulatory Specifications for
Authors: Nick Peter A. 
Published: September 2006

AbstractThis article provides a general survey of the chemical and physical analyses of light and mid‐range hydrocarbon fuels needed to satisfy the environmental and safety requirements of the refining and transport industries. Since the inception of the oil and automobile industries, emissions from vehicles and from fuel refineries have taken a back seat to the performance factors of the fuels themselves. In the middle of the 1900s, new environmental requirements became a commercial consideration as governments, and to a lesser extent, industrial consortia, began to impose requirements on the fuels which had little or nothing to do with performance in the engine. This article will attempt to enumerate the most prevalent of these testing specifications and provide a modest amount of information about what they involve and why they exist. At the time the original draft of this work was written in 1999, the imposition of several new regulatory criteria in the United States had just been imposed on most of the fuels production companies. Few new regulations have been enacted in the last few years (1995+) prior to this article's printing, but there have been numerous serious proposals for such new legislation and several more geographical areas have come under existing and more stringent legislation. We have tried to assess where future regulations will lead and what specifications and tests might deal with these limits.In general, we will not deal here with the engine performance specifications. These are detailed far more adequately elsewhere in the literature. This article will not provide a long treatise on the formulation of transportation fuel manufacturing processes, and neither will it delve deeply into the testing methodology. Enough of these three subjects will be presented to allow the reader to put the regulatory specifications and what they entail into perspective. The emphasis is slanted towards the specification of gasoline range fuels, primarily caused by the great predominance of these commodities, but we do try to cover the heavier transport fuels in detail as well. There is considerable overlap in several of the specifications, at least in terms of methodology, even if the specification document number perhaps differs from light to heavier fuels.The various testing specifications are presented by a fairly succinct description and are categorized by test type and by species analysis requirements. An attached glossary will enable the reader to become acquainted with the jargon of emissions compliance and refinery technology, since these are both linked to intelligent discussion of fuels production and usage.
High‐temperature Simulated Distillation Applications in Petroleum Characterization
Authors: Villalanti Dan C. , Raia Joseph C. , Maynard Jim B. 
Published: September 2006

Abstract

Simulated distillation (SimDist) is a gas chromatography (GC) technique which separates individual hydrocarbon components in the order of their boiling points, and is used to simulate the time‐consuming laboratory‐scale physical distillation procedure known as true boiling point (TBP) distillation. The separation is accomplished with a nonpolar chromatography column using a gas chromatograph equipped with an oven and injector that can be temperature programmed. A flame ionization detector (FID) is used for detection and measurement of the hydrocarbon analytes. The result of SimDist analysis provides a quantitative percent mass yield as a function of boiling point of the hydrocarbon components of the sample. The chromatographic elution times of the hydrocarbons are calibrated to the atmospheric equivalent boiling point (AEBP) of the paraffins reference material. The SimDist method ASTM (American Society for Testing and Materials) D2887 covers the boiling range 55–538 °C (100–1000 °F) which covers the n‐alkanes (n‐paraffins) of chain length about C
5
–C
44
. The high‐temperature simulated distillation (HTSD) method covers the boiling range 36–750 °C (97–1382 °F) which covers the n‐alkane range of about C
5
–C
120
. A key difference between ASTM D2887 and HTSD is the ability of the latter technique to handle residue‐containing samples (i.e. material boiling > 538 °C, 1000 °F). SimDist and laboratory‐scale physical distillation procedures are routinely used for determining boiling ranges of petroleum crude oils and refined products, which include crude oil bottoms and residue processing characterization. The boiling point with yield profile data of these materials are used in operational decisions made by refinery engineers to improve product yields and product quality. Data from SimDists are valuable for computer modeling of refining processes for improvements in design and process optimization. Precise yield correlations between HTSD and crude assay distillation (methods ASTM D2892 and D5236) have allowed HTSD to be successfully used in place of physical distillation procedures. This has given the refiner the ability to rapidly evaluate crude oils for selection of those with economic advantages and more favorable refining margins. SimDist methods are becoming more widely used in environmental applications. HTSD is useful for characterizing hydrocarbons which can be present as soil and water contaminants; for example, to map and follow hydrocarbon removal processes.
Use of Inspection Properties to Predict Hydrocarbon Fraction Physical Properties
Authors: Nick Peter A. 
Published: September 2006

AbstractThe chemical complexity of petroleum products has, until recently, precluded calculational techniques based on a definitive analysis of the molecular species involved. Instead, readily observed or easily (quick and inexpensively) measured macroscopic properties (gravity, boiling range, etc.) have been used to correlate information empirically. In some instances, the predictions have been “tweaked” on a local data‐centric basis or extended by quasi‐theoretical analysis.Recent computer‐aided advancements134in multivariate electromagnetic emission, NMR (nuclear magnetic resonance) and/or MS (mass spectroscopy) analyses allow for the reliable and repeatable use of much more detailed experimental data. The ability to speciate cuts by individual chemical components will revolutionize both refining and regulation of refined products in response to the availability of quality data.So why would one bother with older analysis and prediction methods? It is likely, given the operational sophistication and investment costs needed to deliver this highly speciated information properly, that the old ways will die but slowly. Most refineries and petrochemical plants try to get by with the minimum amount of expensive on‐line analyzers. Multivariate data generation is not yet at a state where it can easily be used for real‐time process or even product quality control. This barrier will exist for some time to come.The historical development of crude oil processing technology has generated a great volume of data and “general” correlations, some contradictory. Most of the data upon which these methods are based have been around for 60 or more years. Many have withstood the “test of time”, being examined and verified by numerous researchers both public and private. Some of the precision of the older data may not be as good as what is generated today, but new entries to various refinery products' databanks seem to confirm the validity of the best of the older procedures and data.The classical methods allow one to impute several otherwise unavailable characterizing pieces of data. It is essential that those engaged in the design and analysis of refinery units (which have multiple feed and product streams) become familiar with classical terminology and techniques, and eventually acquire an intuitive sense of what constitutes the “best answer” when confronted with several conflicting alternatives. The subject of this article is the proper methodology of imputing this knowledge from whatever data are at hand.
Lube Products. Molecular Characterization of Base Oils
Authors: Montanari Luciano 
Published: September 2006

AbstractBase oils used in the formulation of lubricant products are a complex mixture of paraffinic (prevalently branched), aromatic and naphthenic (cycloparaffinic) molecules ranging in carbon number from 20 to 40+. Most automotive crankcase oils, accessory fluids, and many industrial lubricants contain in excess of 80% base oil in their “finished” formulation.The compositional analysis of Lube base oils is usually obtained by a two‐step procedure. The first step separates the aromatic and saturated fractions by column chromatography (American Society for Testing and Materials, ASTM D2549). The aromatic fraction is then further characterized by mass spectrometry (ASTM D3239) and the saturated subclasses of paraffins and cycloparaffins are measured by a different mass spectrometry method (ASTM D2786).Recently the Lube base oils have been characterized at the molecular level by means of nuclear magnetic resonance (NMR) spectroscopy. The conventional NMR spectra have the problem of signal overlap due to the presence of a great number of isomers in the base oil composition.To overcome the problem of signal overlap, some selected multiplet subspectral carbon‐13 nuclear magnetic resonance (13C‐NMR) analyses were developed and, in particular, gated spin echo (GASPE) and distortionless enhancement by polarization transfer (DEPT) have been applied to obtain quantitative CHnsubspectra in petroleum fractions.Usually the quantitative data obtained from GASPE have a better accuracy than those from DEPT and it will be shown how GASPE is applied to study the molecular characteristics of the aliphatic moieties of base oils of a different nature.On the basis of the GASPE data and of the average molecular mass obtained via vapor pressure osmometry (VPO), the average number of branches and aliphatic rings can be calculated. Moreover, on the basis of GASPE, the distribution of side chain lengths and the positions of the methyl groups along the straight chain (methyls are the only groups for which the positions are directly obtained from NMR spectra) were obtained.All these structural features are related to the finished lubricant's performance in both crankcase and industrial applications.