Carbamate pesticides, supercritical fluid

L. Sun and H.K. Lee, Optimization of microwave-assisted extraction and supercritical fluid extraction of carbamate pesticides in soil by experimental design methodology. J. ChromatogrA 1014 (2003) 165-177. 

A Izquierdo, MT Tena, MD Luque de Castro, M Valcarcel. Supercritical fluid extraction of carbamate pesticides from soils and cereals. Chromatographia42 206-212, 1996. 

This chapter deals with the properties of carbamate pesticides, many of which influence the design and choice of analytical methods for their determination. It reviews the chromatographic techniques used to quantify carbamate pesticides in environmental samples, with special emphasis on GC and LC. Other chromatographic techniques, viz., capillary electrophoresis (CE), thin-layer chromatography (TLC), supercritical fluid chromatography (SFC), and sample preparation procedures, are also discussed. 

The procedure to be used to extract carbamate pesticides from environmental samples depends on their polarity and on the type of sample matrix involved. Various choices exist for the extraction of pesticides ranging from conventional procedures (e.g., Soxhlet extraction, liquid-liquid extraction (LLE), evaporation, steam distillation) to new methodologies including solid-phase extraction (SPE), solid-phase microextraction (SPME), supercritical fluid extraction (SEE), matrix solid-phase dispersion (MSPD), accelerated solvent extraction (ASE) and microwave-assisted extraction. " ... 

Many analytes that are not amenable to GC (e.g., thermolabile compounds) can be separated by SFC. Separations via SFC are often more efficient and faster than traditional LC analyses. Wider coverage of supercritical fluid methods can be found in the literature on SFC. " This technique has also been employed for the determination of carbamate pesticides in environmental samples (see Table 24.5). ... 

Packed-column supercritical fluid chromatography (PSFC) is currently competitive with LC and GC as it combines the speed and efficiency of GC with the extensive selectivity adjustment capabilities of LC, thereby facilitating the determination of polar and thermolabile compounds. Thus, carbamate pesticides have been determined by PSFC in river water and soil. ... 

Wright, B. W. and Smith, R. D., Rapid capillary supercritical-fluid chromatographic analysis of carbamate pesticides, J. High Resolut. Chromatogr. Commun., 8, 8-11, 1985. 

One of the most intensively examined type of pesticides handled under PBl conditions were the chlorinated phenoxy acids and their esters which were determined in water [82-86] and soil samples [83, 86]. Even results of an interlaboratory comparison study of 10 chlorinated phenoxy acids using PBl or TSP ionisation were published by Jones et al. [37] [87]. Statistically significant differences were observed between the interfaces and under these conditions PBl was found to have a better precision than TSP [87]. Betowsld et al. [88] observed thermal degradation induced by residence time in the ion source and the influence of ion source temperature in the ionisation of the chlorinated phenoxy acid derivatives 2,4-D and MCPA. Several authors successfully examined a large number of different carbamate pesticides [67, 89, 90] and their transformation products by PBl-LC-MS [89, 90], by PBl-FIA-MS (flow injection analysis) [67] or by supercritical fluid chromatography (SEC) PBl-interfaced to MS [91],... 

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