Environmental sampling

Conklin AR, Jr. Field Sampling Principles and Practices in Environmental Analysis. New York Marcel Dekker 2004, pp. 224-245. 

Weber G, Messerschmidt J, von Bohlen A, Alt F. Effect of extraction pH on metal speciation in plant root extracts. Fresenius. J. Anal. Chem. 2001 371 921-926. 

Gottlein A, Matzner E. Microscale heterogeneity of addity related stress-parameters in the soil solution of a forested cambic podzol. Plant Soil 1997 192 95-105. 

Helmke PA, Sparks DL. Lithium, sodium, potassium, rubidium, and cesium. In Bartels JM (ed.), Methods of Soil Analysis Part 3 Chemical Methods. Madison, WI  

Soil Science Society of America and American Society of Agronomy 1996, pp. 551-574. 

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Csuros, M. Environmental Sampling and Analysis for Technicians, Lewis Boca Raton, 1994. 

The environmental sampling of waters and wastewaters provides a good illustration of many of the methods used to sample solutions. The chemical composition of surface waters, such as streams, rivers, lakes, estuaries, and oceans, is influenced by flow rate and depth. Rapidly flowing shallow streams and rivers, and shallow (<5 m) lakes are usually well mixed and show little stratification with... 

Clement, R. E. Environmental Sampling for Trace Analysis, Anal. Chem. 1992, 64, 1076A-1081A. 

The following sources may be consulted for further details regarding the collection of environmental samples. The paper by Benoit and colleagues provides a good discussion of how easily samples can be contaminated during collection and preservation. 

Benoit, G. Hunter, K. S. Rozan, T. F. Sources of Trace Metal Contamination Artifacts During Collection, Handling, and Analysis of Freshwaters, Anal. Chem. 1997, 69, 1006-1011. Keith, L. H., ed. Principles of Environmental Sampling, American Chemical Society Washington, DC, 1988. 

Keith, L. H. Environmental Sampling and Analysis—A Practical Guide, Lewis Publishers, Boca Raton, EL, 1991. 

Van Loon, J. G. Selected Methods of Trace Metal Analysis Biological and Environmental Samples. Wiley-lnterscience New York, 1985. 

Environmental Applications Although ion-selective electrodes find use in environmental analysis, their application is not as widespread as in clinical analysis. Standard methods have been developed for the analysis of CN , F , NH3, and in water and wastewater. Except for F , however, other analytical methods are considered superior. By incorporating the ion-selective electrode into a flow cell, the continuous monitoring of wastewater streams and other flow systems is possible. Such applications are limited, however, by the electrode s response to the analyte s activity, rather than its concentration. Considerable interest has been shown in the development of biosensors for the field screening and monitoring of environmental samples for a number of priority pollutants. 

Quantitative voltammetry has been applied to a wide variety of sample types, including environmental samples, clinical samples, pharmaceutical formulations, steels, gasoline, and oil. 

Selected Examples of the Application of FIA to the Analysis of Environmental Samples... 

Complex environmental samples originate from diverse matrices (the predominant material of which the sample to be analyzed is composed). These matrices, usually either water or soil/sediment, can contain as many as 50 to 100 organic components at widely varying concentrations. The EPA approach to the analysis of these samples involves the analysis of specific (or target) compounds and the use of authentic standards for quality control. The current number of standards in the EPA repository is about 1500, and their analysis is covered by various approved methods. 

Identification of some target compounds in an environmental sample. The report lists the closeness of match and the estimated quantities for the listed compounds. 

Accurate, precise isotope ratio measurements are important in a wide variety of applications, including dating, examination of environmental samples, and studies on drug metabolism. The degree of accuracy and precision required necessitates the use of special isotope mass spectrometers, which mostly use thermal ionization or inductively coupled plasma ionization, often together with multiple ion collectors. 

Numerous collections of herbicide analysis methods have been pubUshed (276—279). An increased emphasis has been placed on the first step in the environmental sampling process, that of obtaining a representative, uncontaminated sample. If this is to be accompUshed, consideration must be made of such factors as sample size and location (280—283). After the sample has been obtained, it must be stored in such a way as to minimize degradation. This generally consists of refrigeration, possibly preceded by some type of drying (284). 

L. H. Keith, Principles of Environmental Sampling, American Chemical Society, Washington, D.C., 1988. 

L. H. Keith, Practical Guidefor Environmental Sampling andMnalysis, Lewis Pubhshers, Chelsea, Mich., 1990. 

Because of the large number of samples and repetitive nature of environmental analysis, automation is very important. Autosamplers are used for sample injection with gc and Ic systems, and data analysis is often handled automatically by user-defined macros in the data system. The high demand for the analysis of environmental samples has led to the estabUshment of contract laboratories which are supported purely by profits from the analysis. On-site monitoring of pollutants is also possible using small quadmpole ms systems fitted into mobile laboratories. 

The widespread usage of phthalates in flexible PVC has resulted in many investigations being made of their concentration in the environment. Unfortunately the ubiquitous presence of phthalates in laboratory chemicals and equipment has caused problems in the analysis of very low concentrations of phthalates in environmental samples and has led to erroneously high levels being reported. 

A large number of radiometric techniques have been developed for Pu analysis on tracer, biochemical, and environmental samples (119,120). In general the a-particles of most Pu isotopes are detected by gas-proportional, surface-barrier, or scintillation detectors. When the level of Pu is lower than 10 g/g sample, radiometric techniques must be enhanced by preliminary extraction of the Pu to concentrate the Pu and separate it from other radioisotopes (121,122). Alternatively, fission—fragment track detection can detect Pu at a level of 10 g/g sample or better (123). Chemical concentration of Pu from urine, neutron irradiation in a research reactor, followed by fission track detection, can achieve a sensitivity for Pu of better than 1 mBq/L (4 X 10 g/g sample) (124). 

A number of techniques have been developed for the trace analysis of siUcones in environmental samples. In these analyses, care must be taken to avoid contamination of the samples because of the ubiquitous presence of siUcones, particularly in a laboratory environment. Depending on the method of detection, interference from inorganic siUcate can also be problematic, hence nonsiUca-based vessels are often used in these deterrninations. SiUcones have been extracted from environmental samples with solvents such as hexane, diethyl ether, methyl isobutylketone, ethyl acetate, and tetrahydrofuran (THF)... 

Zinc smelters use x-ray fluorescence spectrometry to analyze for zinc and many other metals in concentrates, calcines, residues, and trace elements precipitated from solution, such as arsenic, antimony, selenium, tellurium, and tin. X-ray analysis is also used for quaUtative and semiquantitative analysis. Electrolytic smelters rely heavily on AAS and polarography for solutions, residues, and environmental samples. 

A gas chromatographic determination of benzotrichloride and related compounds ia the work environment, after adsorption on a polymeric adsorbant and desorption with CCl has been reported (61). Trace amounts of benzyl chloride, benzal chloride, and benzotrichloride ia environmental samples can be analyzed by Method 8120 of EPA ManualSW-846 with modifications (62). 

The environmental impact of PCNs has not been extensively investigated and PCNs are not routinely measured in analytical studies of extracts from environmental samples. However, PCNs have been identified in birds of prey in Britain (69) and The Netherlands (70), in a drainage ditch in Florida, and in sediments from San Francisco Bay (71). 

For selective estimation of phenols pollution of environment such chromatographic methods as gas chromatography with flame-ionization detector (ISO method 8165) and high performance liquid chromatography with UV-detector (EPA method 625) is recommended. For determination of phenol, cresols, chlorophenols in environmental samples application of HPLC with amperometric detector is perspective. Phenols and chlorophenols can be easy oxidized and determined with high sensitivity on carbon-glass electrode. 

Acetohydrazidines ai e interesting for the analytical usage. They were proposed as the reagents for the determination of Ni(II) in different environmental samples. 2-(4-methoxybenzoyl)-4-(2-nitrophenyl)aceto-hydrazidine forms the blue complex 1 1 with Ni(II). The extraction was carried out with n-butanole saturated with water. The reagent excess was excluded by CCl. ... 

Application of rotating coiled columns has become attractive for preparative-scale separations of various substances from different samples (natural products, food and environmental samples) due to advantages over traditional liquid-liquid extraction methods and other chromatographic techniques. The studies mainly made during the last fifteen years have shown that using rotating coiled columns is also promising for analytical chemistry, particularly for the extraction, separation and pre-concentration of substances to be determined (analytes) before their on-line or off-line analysis by different determination techniques. 

GENERAL STRATEGY FOR IDENTIFICATION OF TOXIC CHEMICALS IN ENVIRONMENTAL SAMPLES... 

Identification of stmctures of toxic chemicals in environmental samples requires to use modern analytical methods, such as gas chromatography (GC) with element selective detectors (NPD, FPD, AED), capillary electrophoresis (CE) for screening purposes, gas chromatography/mass-spectrometry (GC/MS), gas chromatography / Fourier transform infra red spectrometry (GC/FTIR), nucleai magnetic resonance (NMR), etc. 

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