Samples agricultural

Turner, C., Overview of modem extraction techniques for food and agricultural samples, in Modern Extraction Techniques Food and Agricultural Samples, ACS Symposium Series, No. 926, Turner, C., Ed., Washington, D.C., 2006, chap. 1. 

The natural matrix materials, which are similar to the actual environmental, clinical, food, or agricultural samples analyzed, are used to validate the complete analytical measurement process including extraction, cleanup and isolation procedures, and the final chromatographic separation, detection, and quantification. 

Liquid samples, in particular aqueous in nature, are the most frequently encountered (waste water, food and beverages, biological fluids, soil and agricultural samples). SPE is a well-established technique, which is... 

Ferguson, B.S., D.E. Kelsey, T.S. Fan, and R.J. Bushway (1993). Pesticide testing by enzyme immunoassay at trace levels in environmental and agricultural samples. Sci. Total Environ., 132 415 -28. 

The chromatograms show linearity in response with the amount of carbaryl injected in both the absorbance and fluorescence modes. Practical agricultural samples when analyzed for carbaryl, however, require a preliminary column cleanup before injection into the HPLC in order to preserve the integrity of the HPLC Column. 

IMPROVEMENTS IN UNDERGROUND GAMMA-RAY SPECTROMETRY AND THE APPLICATION OF MEASURING RADIOACTIVITY IN AGRICULTURAL SAMPLES... 

Central Statistical Authority (Federal Democratic Republic of Ethiopia). 2005. Agricultural Sample Survey. Volume IV. Report on land utilization. 

Modern Extraction Techniques Food and Agricultural Samples... 

Modem extraction techniques food and agricultural samples / Charlotta Turner, editor sponsored by the ACS Division of Agricultural and Food Chemistry. 

This book is based on the symposium entitled Modem Extraction Techniques for Food and Agricultural Samples, which was arranged by the Division of Agricultural and Food Chemistry during the American Chemical Society s 227th national meeting in Anaheim, California, held March 28-April 2,2004. 

There are several parameters to consider in SPME, such as extraction mode (HS-SPME or DI-SPME), type and thickness of fiber coating, extraction time, sample properties (analyte concentration, pH, buffer, temperature, agitation) and analyte desorption. Applications and optimization of SPME for food and agricultural samples are discussed in the excellent review articles (9J7). SPME fibers are commercially available from Supelco (Bellafonte, PA). 

Solutions for Online Coupling of Extraction and Chromatography in the Analysis of Food and Agricultural Samples... 

Even with the emergence of advanced techniques of separation and identification, it is rarely possible to analyze food and agricultural samples without manipulation. Particularly solid and semi-solid samples typically require complex, multistep sample preparation procedures. During recent years, much effort has been invested in the development of separation techniques, especially chromatography. However, the role of sample pretreatment is too often neglected in the method development. Often, the sample preparation is not at the same high... 

In the field of food and agricultural samples, relatively few on-line systems based on solvent extraction have been developed. SFE, PLE and SAE have been combined on-line with LC or GC (7-20). In theory, it would also be possible to use MAE in on-line combination, but so far, only one application for environmental analysis has been reported (21). 

If the analytes of interest are volatile or semivolatile, solvent extraction is not always necessary, and head-space techniques (HS) can be applied for the analysis, typically utilizing GC as the final analytical step. HS analysis can be defined as a vapor-phase extraction, involving ftrst the partitioning of analytes between a non-volatile liquid or solid phase and the vapor phase above the liquid or solid. The vapor phase is then transferred further and either analysed as vapor or (ad)sorbed to an (ad)sorbent. The head-space techniques have been widely utilized in the analysis of volatiles, such as fi agrances and aroma compounds, in various food and agricultural samples (81-84). The dynamic head-space (DHS), or purge-and-trap technique, is easily coupled on-line with GC. In an on-line system, desorption of trapped analytes for subsequent analysis is usually performed using on-line automated thermal desorption (ATD) devices. 

The number of on-line methods using solvent/fiuid extraction developed for the analysis of solid food and agricultural samples is still small. The solventless... 

Solid phase extraction (SPE) techniques are emerging as the perhaps most popular alternatives to liquid-liquid extraction for sample preparation of food and agricultural samples. The principle of SPE is now fully described (9,10). Most sorbents are now available as disks, cartridges or precoiumns (11,12). Among the advantages of SPE, is die easiness for the method to be automated and the possibility for simultaneous combination of extraction and enrichment of the analytes (12). This reduces the whole analytical scheme compared to liquid-... 

Membrane based extractions are capable of complementing conventional techniques (liquid-liquid and solid phase extractions) in food and agricultural sample preparation. Their attractiveness in sample preparation is based on their selectivity and ability to tolerate samples with high organic content and/or dissolved solid. They can also be easily automated and interfaced to other separation techniques. However, despite these advantages, membrane based extractions especially SLM extraction and MMLLE techniques have not been applied much to food and agricultural samples as compared to PME techniques. 

---