Sample preparation environmental science

Thin-layer chromatography (TLC) is one of the most popular and widely used separation techniques because of its ease of use, cost-effectiveness, high sensitivity, speed of separation, as well as its capacity to analyze multiple samples simultaneously. It has been applied to many disciplines including biochemistry [1,2], toxicology [3,4], pharmacology [5,6], environmental science [7], food science [8,9], and chemistry [10,11]. TLC can be used for separation, isolation, identification, and quantification of components in a mixture. It can also be utilized on the preparative scale to isolate an individual component. A large variety of TLC equipment is available and discussed later in this chapter. 

Preparation of an environmental sample for delivery to the sensor and the sample cleanup afterwards are often the rate-limiting steps in the detection of biological agents, as well. Even for biodetection, sample preparation is a chemistry and materials science issue, currently accomplished using membranes and surface-active chemistries, binders, and ligands. Biological sample preparation remains an embryonic field. 

Swartz, E., Stockburger, L. and Gundel, L.A. (2003) Recovery of semivolatile organic compounds during sample preparation implications for characterization of airborne particulate matter. Environmental Science and Technology, 37, 597-605. 

Nano-HPLC has been used for the separation and identification of molecules in different matrices such as proteomic, pharmaceutical, and environmental sciences. Of course, sample preparation is the most important task prior to nano-HPLC analysis, which has already been discussed in this book. The applications of nano-HPLC in different matrices are discussed in the following sections. 

Pawliszyn, J. 2002. Sampling and sample preparation for field and laboratory. In J. Pawliszyn (ed.), Comprehensive Analytical Chemistry, Vol. XXXVII, pp. 389—477. Amsterdam Elsevier Science B.V.0. Ouyang, G. and J. Pawliszyn. 2006. SPME in environmental analysis. Anal. Bioanal. Chem. 386 1059-1073. 

The book is intended to be a reference book for scientists who use sample preparation in the chemical, biological, pharmaceutical, environmental, and material sciences. The other objective is to serve as a text for advanced undergraduate and graduate students. 

Wenzel, W.W. Blum, W.E.H. (1999) Effect of sampling, sample preparation and extraction techniques on mobile metal fractions in soils, in D.C. Adriano, Z.-S. Chen, S.-S. Yang, and I.K. Iskandar (eds), Biogeochemistry of trace metals, Advances in Environmental Sciences, Science Reviews, Northwood, pp. 121-172. 

Whether the ionization is positive or negative, TIMS requires careful sample preparation, often involving considerable chemical processing to separate and purify the element of interest. TIMS finds applications in geoscience, environmental analysis, cosmochemistry, biosciences, medicine, material science, and physics. Samples generally include soil, minerals, meteorites, and biological tissue. More information on the specifics of the TIMS technique and its applications is in the monograph by De Laeter (2001). 

The analytical chemistry literature contains novel research that utilizes SPE as the principal sample preparation technique. Major journals in which it is likely that research using SPE will be presented include Analytical Chemistry and the applied biennial reviews, Journal of Chromatography, Journal of Chromatographic Science, Analytica Chimica Acta, LC-GC The Magazine of Separation Science, Environmental Testing Analysis, American Laboratory, American Environmental Laboratory, and Environmental Science and Technology. 

Solid-phase extraction (SPE) is the method of sample preparation that concentrates and purifies analytes from solution by sorption onto a disposable solid-phase cartridge, followed by elution of the analyte with an appropriate solvent. The SPE technique was developed in the mid-1970s as an alternative means of liquid-liquid extraction but become particularly attractive for its automation, parallel purification, and pre-concentration. Since 1995, SPE has been applied in various fields, environmental, food sciences, biomedical analyses, pharmaceutical analyses, and organic synthesis. " There are a numbers of publications and reviews on the subjects of development of new solid-phase supporting materials, instrumentation and device, techniques, and theoretical aspect. ... 

Pawliszyn J (2002) Sampling and Sample Preparation for Field and Laboratory. In Barcelo D (ed.) Comprehensive Analytical Chemistry, vol. 37. Amsterdam Elsevier. Shang DY, MacDonald RW, and Ikonomou MG (1999) Persistence of nonylphenol ethoxylate surfactants and their primary degradation products in sediments from near a municipal outfall in the Strait of Georgia, British Columbia, Canada. Environmental Science and Technology 33 1366-1372. 

See alsa Chromatography Multidimensional Techniques. Environmental Analysis. Extraction Solid-Phase Extraction. Food and Nutritional Analysis Sample Preparation Contaminants Pesticide Residues. Forensic Sciences Drug Screening in Sport Illicit Drugs. Herbicides. Liquid Chromatography Instrumentation Clinical Applications Food Applications. Mass Spectrometry Peptides and Proteins. Pesticides. Pharmaceutical Analysis Sample Preparation. Proteomics. Sample Handling Automated Sample Preparation. Water Analysis Organic Compounds. 

Sample preparation using solid environmental and biological samples has been an active area in the analytical sciences for the past few decades. 

Therefore, with RS, direct analysis can be made of aqueous systems without the need of sample extraction, purification, or preparation, as is needed for many other analytical techniques. Hence, RS is well suited for many environmental applications, including continuous monitoring applications when analyte concentrations are adequately high. The ability to directly analyze aqueous systems reduces the probability that the analyte(s) of interest will change prior to or during analysis. Also, many environmental scientists are interested in the behavior and fate of chemicals in water. For these cases, water is not a passive solvent but, instead, typically drives the processes under study. Removing the chemical from water for analysis is simply not an option. These types of applications (some of which are presented in Section IV) are where RS can, perhaps, have the greatest impact on environmental science. 

GC-MS is still widely used technique in environmental, forensic, and planetary (space) sciences. It is, however, limited to volatile and thermally stable compounds as they are injected to the GC via a high-temperature (250-300°C) injection port. Nonvolatile compounds can be analyzed after specific derivatiza-fion such as methylafion, silylafion, etc. however, that requires additional sample preparation time. This is not always feasible as HPLC-MS is a better technique for a large variety of nonvolatile compounds, including those of biological importance. These include drugs and their metabolites, peptides, proteins, oligosaccharides, and oligonucleotides. For more details about GC/MS operation... 

We thank Joe Steinbacher and Bernie Crimmins and others at CBL for help with sample collection, and for help in bottle preparation and other laboratory activities. This study was funded by the EPA STAR Air Toxics Program, Grant R825245-01. This is Contribution No. 3462, Chesapeake Biological Laboratory, Center for Environmental Science, University of Maryland. 

---