Extract cleaned

Extract-Clean SPE Sample Preparation Guide Volume I, Bulletin No. 83, Alltech Associates, Inc. 

Miller and Hawthorne [416] have developed a chromatographic method that allows subcritical (hot/liquid) water to be used as a mobile phase for packed-column RPLC with solute detection by FID, UV or F also PHWE-LC-GC-FTD couplings are used. Before LC elution the extract is dried in a solid-phase trap to remove the water. In analogy to SFE-SFC, on-line coupled superheated water extraction-superheated water chromatography (SWE-SWC) has been proposed [417]. On-line sample extraction, clean-up and fractionation increases sensitivity, avoids contamination and minimises sources of error. 

Hinman et al. [492] have compared SFE and ASE in the extraction of antioxidants from LDPE. Comparable extraction yields were obtained with both techniques. However, sample clean-up was necessary after ASE , while with SFE the extract could be analysed directly without any post-extraction clean-up. Supercritical fluid extraction of 15 polymer additives (AOs, UVAs, process lubricants, flame retardants and antistatic agents) from eight PS formulations was compared to dissolu-tion/precipitation extractions [557], Additive recoveries were comparable. Numerous additional comparisons can be found under the specific headings of the extraction techniques (Sections 3.3 and 3.4). 

Table 4.25 lists the main characteristics of headspace sampling. In HS-GC sample preparation is very often limited to placing a sample in a vial. Sample extraction, clean-up and preconcentration are not necessary. Elimination of solvents in preparing samples for GC has several benefits ... 

Fish Polytron (methanol) or ball mill (hexane) extraction clean-up by GPC and alumina column chromatography GC/NPD 0.01 pg/g 79-97 Muiret al. 1981... 

Rainwater Solvent extraction clean-up by liquid-liquid partition fractionation on silica gel plates Capillary GC/FID and GC/MS Not specified >80 Kawamura and Kaplan 1983... 

Food (fish) Grinding with petroleum ether solvent extraction clean-up by liquid-liquid partition, Florisil column chromatography GC/NPD 0.1 ppm Not specified Lombardo and Egry 1979... 

Aspec is designed to receive up to 108 samples. The system is compatible with most standard disposable extraction columns. Analytichem Bond-Elut Baker SPE, Supelco Supelclean, Alltech Extract Clean, etc. There is a choice of more than 20 different stationary phases. 

Christman et al. [72] gave details of procedures for extraction, clean-up, and concentration of samples of soil prior to the determination of their content of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by gas chromatography and by gas chromatography-mass spectrometry. Instrumental parameters are also included. Some typical results are tabulated. 

Novikova [21] has reviewed the literature (209 references) covering the extraction, clean-up and analysis of organochlorine (and organophosphorus) insecticides in soil. Johnson and Starr [22] and Chiba and Morley [4] have studied factors affecting the extraction of Dieldrin and Aldrin from different soil types ultrasonic extraction was recommended by these workers. Lopez-Avila et al. [23] used microwave assisted extraction to extract chlorinated insecticides from soils. 

Novikova [21] has reviewed the literature (209 references) covering the extraction, clean-up and analysis of organophosphorus insecticides in soil (also food). 

Cappon and Crispin-Smith [59] have described a method for the extraction, clean-up and gas chromatographic determination of alkyl and aryl mercury compounds in sediments. The organomercury compounds are converted to their chloroderivatives and solvent extracted. Inorganic mercury is then isolated as methylmercury upon reaction with tetramethyltin. The initial extract is subjected to a thiosulphate clean-up and the organomercury species are isolated as their bromoderivatives. Total mercury recovery was in the range 75-90% and down to lpg kg-1 of specific compounds can be determined. 

It is quite clear that in the near future extraction of non-ionic surfactants from solid matrices will be based on SFE, PLE and sonication methods. The initial costs for SFE/PLE equipment will be earned back quickly by the reduction of man-hours and solvent consumption per sample. For sonication methods, not even this financial barrier is present. More emphasis must be laid on quality assurance of the extraction, clean-up and detection methodologies. The recently available 13C-labeled standards will help to account for matrix... 

Compound Matrix Extraction Clean- up/treatment Identification/ quantification Concentration (pgL-1) Concentration (mg kg-1) Reference... 

Compound Matrix Extraction Clean- Identification/ Concentration Concentration Reference... 

Source of contamination Compound Extraction Clean-up/treatment Identification/quantification Reference... 

Milk Soxhlet extraction clean-up GC/MS 0.05 ng/g 66 (average) Bush et al. 

B1 ood Whole serum or bl ood Acidification solvent GC/ECD extraction clean-up with concentrated sulfuric sulfuric acid No data 84.7 (serum) 85.1 (whole blood) Waliszewski and Szymczynski 1991 ... 

Mirex can be extracted from feces with hexane-acetonitrile and the extract cleaned up on alumina/Florisil columns, then analyzed using GC/ECD. Sensitivity, precision, and accuracy data for feces were not reported (Gibson et al. 1972). 

Lake sediments Ultrasonic solvent extraction clean-up on Florisil column separation of mi rex and photomi rex from PCBs using charcoal -polyurethane column GC/ECD No data <0.05 ppm 99.9-100 (mi rex) 95.1-99.1 (photomi rex) Chau and Babjak 1979... 

XAD-2 resin vacuum filtration solvent extraction clean-up on Florisil column... 

Sediment and soil samples are homogenized and extracted. Clean-up procedures are required prior to analysis by GC/ECD or GC/MS techniques (Lopez-Avila et al. 1992 Moseman et al. 1977 Saleh and Lee 1978 Tiernan et al. 1990). For sediment, soil, and sludge, recoveries were good (>85%) with sensitivity in the low ppb range (Moseman et al. 1977 Saleh and Lee 1978). Precision is good ( <6% RSD) (Saleh and Lee 1978). Analytical difficulties (unacceptable recovery not detectable using second capillary GC column) were reported (Lopez-Avila et al. 1992 Tiernan et al. 1990). 

Bovine liver, rumen content (partially digested grain and vegetation mixture) Extraction of homogenized sample with methanol-dichloromethane (10-90, v/v) followed by gel permeation chromatography and silica gel solid phase extraction clean-up. GC/FPD 0.01-0.05 p/g using 5 g sample Rumen content 95 (3% RSD) at 0.1 pg/g liver 88 (5% RSD) at 0.05 / Holstege et al. 1991... 

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