scholarly journals Sample Preparation in the Analysis of Pesticides Residue in Food by Chromatographic Techniques

10.5772/13497 ◽  
2011 ◽  
Author(s):  
Guan Huat ◽  
Mee-Kin Chai
Keyword(s):  
Sample Preparation ◽  
Chromatographic Techniques ◽  
Pesticides Residue

Analytical Methodology for the Determination of Organochlorine Pesticides in Vegetation

2012 ◽  
Vol 95 (5) ◽  
pp. 1291-1310 ◽  
Author(s):  
Elisa Beceiro-González ◽  
María J González-Castro ◽  
Soledad Muniategui-Lorenzo ◽  
Purificación López-Mahía ◽  
Darío Prada-Rodríguez
Keyword(s):  
Sample Preparation ◽  
Solid Phase Extraction ◽  
Organochlorine Pesticides ◽  
Pesticide Residues ◽  
Solid Phase ◽  
Liquid Extraction ◽  
Stir Bar Sorptive Extraction ◽  
Phase Extraction ◽  
Chromatographic Techniques ◽  
Wide Range

Abstract Due to the extensive use of organochlorine pesticides (OCPs) for agricultural purposes and their high persistence and low biodegradability, they have become an important group of contaminants. Detection and quantification of pesticide residues in food, particularly fruits and vegetables, is of growing concern for producers, consumers, and governments. The most widely used pretreatment for the extraction of pesticides in plants is based on solvent extraction liquid-solid extraction (LSE). LSE can be carried out using Soxhlet, shake-flask, homogenization, sonication, and, more recently, microwave-assisted extraction, pressurized liquid extraction, and supercritical fluid extraction. Furthermore, new analytical procedures using the extraction with sorbents, such as solid-phase micro-extraction, stir bar sorptive extraction, and matrix solid-phase dispersion, have also been used. On the other hand, a wide range of cleanup methods (liquid–liquid extraction, solid-phase extraction, gel permeation chromatography, and dispersive solid-phase extraction; and chromatographic techniques with electron capture detector and mass spectrometry detector; and HPLC with a ultraviolet detector are reported in the literature. This article reviews the applicability, advantages, and disadvantages of various sample preparation techniques (traditional and new techniques) for the analysis of OCPs in different plants and plant materials. It covers more than 15 years of published methods in which pesticide residues have been determined in a wide range of vegetation samples (fruits, horticultural samples, medicinal plants, tree leaves, etc.) by the use of chromatographic techniques after various sample preparation steps. A great number of applications in different plant material are provided. To the best of the authors' knowledge, previously published reviews have not covered as wide and exhaustive range of vegetation matrixes as presented here. A summary of pesticide levels cited in the literature is included.

Analytical Methodology for Sample Preparation, Detection, Quantitation, and Confirmation of N-Nitrosamines in Foods

1981 ◽  
Vol 64 (5) ◽  
pp. 1037-1054
Author(s):  
Joseph H Hotchkiss
Keyword(s):  
Sample Preparation ◽  
Review Paper ◽  
Complex Mixtures ◽  
Nitroso Compounds ◽  
Preparation Time ◽  
Analytical Methodology ◽  
Chromatographic Techniques ◽  
The Past ◽  
Selective Detectors ◽  
Further Development

Abstract Significant advances have been made over the past decade in methodology for the analysis of foods and other samples for volatile N-nitrosamines. Procedures for the isolation, cleanup, and concentration of N-nitrosamines were developed and applied to a broad range of food types. Several chromatographic techniques and systems have also been developed which are capable of resolving AT-nitrosamines in complex mixtures in a single run, and the use of highly selective detectors has decreased sample preparation time while increasing sensitivity and precision. Unequivocal confirmation of N-nitrosamines in foods can now be achieved by mass spectrometry at low to sub-μg/kg levels. However, further development of methodology for nonvolatile N-nitroso compounds is needed. This review paper discusses these and other topics related to the analysis of foods for N-nitrosamines.

scholarly journals Signal enhancement techniques for chromatography detection systems

1997 ◽  
Vol 19 (5) ◽  
pp. 145-152 ◽  
Author(s):  
K. D. Jackson ◽  
S. J. Walton ◽  
D. Campbell
Keyword(s):  
Mass Spectrometry ◽  
Sample Preparation ◽  
Ground Water ◽  
Trace Analysis ◽  
Detection Limits ◽  
Analytical Techniques ◽  
Cost Effective ◽  
Detection Systems ◽  
Chromatographic Techniques ◽  
Lower Detection

The Environmental Protection Act has created a growing need for the measurement and assessment of trace emissions to the environment. This encompasses three main areas of ground, water and the atmosphere. The need to achieve lower emissions has placed a large burden on analytical techniques, particularly in the areas of trace analysis to ppb and ppt levels. Chromatographic techniques are widely used for assessment and measurement of emissions in all three areas. Enhanced detectors using mass spectrometry principles are available to lower detection limits, but these are expensive. Standard chromatography detectors can be used for trace analysis, but this often leads to extensive sample preparation stages to achieve low detection limits. This paper describes the techniques developed by Thomas Swan & Company to introduce a cost effective way of lowering detection limits. The approach taken meets both BATNEEC and BPEO constraints.

Pollutant Identification by Selected Area Electron Diffraction

1974 ◽  
Vol 32 ◽  
pp. 532-533
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker
Keyword(s):  
Thermal Treatment ◽  
Electron Diffraction ◽  
Sample Preparation ◽  
Crystal Structures ◽  
Water Samples ◽  
Environmental Samples ◽  
Short Review ◽  
Selected Area Electron Diffraction ◽  
Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

Preparation of Thin Cadmium Telluride Samples for Electron Microscope Studies

1974 ◽  
Vol 32 ◽  
pp. 548-549
Author(s):  
T. J. Magee ◽  
J. Peng ◽  
J. Bean
Keyword(s):  
Electron Microscope ◽  
Sulfuric Acid ◽  
Solid State ◽  
Sample Preparation ◽  
Cadmium Telluride ◽  
Potassium Dichromate ◽  
Optical Components ◽  
The Past ◽  
Solid State Devices

Cadmium telluride has become increasingly important in a number of technological applications, particularly in the area of laser-optical components and solid state devices, Microstructural characterizations of the material have in the past been somewhat limited because of the lack of suitable sample preparation and thinning techniques. Utilizing a modified jet thinning apparatus and a potassium dichromate-sulfuric acid thinning solution, a procedure has now been developed for obtaining thin contamination-free samples for TEM examination.

A Freeze Shadow Technique for the Preparation of Soft Paint Latexes for Electron Microscopy

1977 ◽  
Vol 35 ◽  
pp. 314-315
Author(s):  
Earl R. Walter ◽  
Glen H. Bryant
Keyword(s):  
Sample Preparation ◽  
High Vacuum ◽  
Vacuum System ◽  
Latex Particles ◽  
New Methods ◽  
Diffusion Pump ◽  
Film Forming ◽  
Routine Basis ◽  
Distribution Studies ◽  
Preparation Techniques

With the development of soft, film forming latexes for use in paints and other coatings applications, it became desirable to develop new methods of sample preparation for latex particle size distribution studies with the electron microscope. Conventional latex sample preparation techniques were inadequate due to the pronounced tendency of these new soft latex particles to distort, flatten and fuse on the substrate when they dried. In order to avoid these complications and obtain electron micrographs of undistorted latex particles of soft resins, a freeze-dry, cold shadowing technique was developed. The method has now been used in our laboratory on a routine basis for several years.The cold shadowing is done in a specially constructed vacuum system, having a conventional mechanical fore pump and oil diffusion pump supplying vacuum. The system incorporates bellows type high vacuum valves to permit a prepump cycle and opening of the shadowing chamber without shutting down the oil diffusion pump. A baffeled sorption trap isolates the shadowing chamber from the pumps.

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