Florisil liquid chromatography

This technique is based on the same separation mechanisms as found in liquid chromatography (LC). In LC, the solubility and the functional group interaction of sample, sorbent, and solvent are optimized to effect separation. In SPE, these interactions are optimized to effect retention or elution. Polar stationary phases, such as silica gel, Florisil and alumina, retain compounds with polar functional group (e.g., phenols, humic acids, and amines). A nonpolar organic solvent (e.g. hexane, dichloromethane) is used to remove nonpolar inferences where the target analyte is a polar compound. Conversely, the same nonpolar solvent may be used to elute a nonpolar analyte, leaving polar inferences adsorbed on the column. 

Plant materials are homogenized with methanol. Hexythiazox residue is extracted with hexane and then transferred to acetonitirile by liquid-liquid partitioning. The acetonitirile is removed by rotary evaporation and the sample is cleaned up using Florisil PR column chromatography. The concentrated eluate is subjected to high-performance liquid chromatography (HPLC) analysis. 

A method for food (fish) has been reported. The sample is ground with sodium sulfate and extracted with petroleum ether. The extract is cleaned up by liquid-liquid partition, followed by Florisil column chromatography. Analysis is performed by GC/NPD. Detection limits are 0.1 ppm recovery was not reported (Lombardo and Egry 1979). 

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... 

A variety of adsorbents, such as alumina, silica gel, Florisil, and various activated carbons, have been employed for carbamate residue cleanup (43). Liquid chromatography on alumina (44-46), silica gel (14), or Florisil (47) has also been used as a cleanup step. 

Fenoxaprop, Fenoxapropetbyl Polycyclic aromatic hydrocarbons Solvent Florisil or alumina High-performance liquid chromatography [79]... 

Celi et al. [538] determined fenoxaprop and fenoxapropethyl in soil by solvent extraction, clean-up on Florisil or alumina cartridge and high-performance liquid chromatography with UV detection at 280 nm. 

Bulk matrix removal by liquid-solid chromatography has been performed on Florisil, silica, modified silica gel, and modified celite [51,108,115,116,121,126, 128, 132]. Silica gel (activated) [51] and the Florisil column chromatography technique [108,121,126,128] have been used to remove lipids from fish muscle, bird eggs and tissues (muscle, liver, fat), and rat tissues (muscle, liver, blood, skin) and for bulk matrix removal of sediment extracts. Extracts have been elut-... 

The most important cleanup procedures are liquid-liquid partition, liquid chromatography in a column of silica, florisil, and/or alumina, gel permeation chromatography, and solid-phase extraction. 

Florisil and sihca columns are used, often in combination with alumina columns, to fractionate the extract into different classes of compound. Both pure silica and acid-treated silica are used for fractionation. High performance liquid chromatography (HPLC) and GPC have also been used for cleanup and fractionation of the extract. 

Normal-phase liquid chromatography can be used to separate interfering compounds from SVOCs, pesticides, and PCBs. Three classical adsorbents—Florisil, alumina, and silicagel—are commonly used, although many other polar adsorbents are available. Table 15.7 shows some of the properties and characteristics of these adsorbents. Prior to the cleanup, the sample extract must be exchanged to a solvent that is compatible with the chromatographic separation. Because they are nonpolar, hexane and methylene chloride are common choices. 

The heavy oil, which contained nearly 90% of the nitrogen in the syncrude, was fractionated by liquid displacement chromatography on Florisil. The nonpolar, nonnitrogen-containing hydrocarbons were washed from the Florisil column with n-heptane, a very weak base concentrate was displaced with benzene, and a weak base concentrate was displaced with benzene-methanol azeotrope. 

Hydrocarbon types were estimated using the substractive method of Poulson (15,16) for the fractions boiling above 175°F. The hydrocarbon compound composition of the C5-175°F naphtha was determined by gas chromatography. Paraffin and naphthene contents of the 175°-350°F naphtha and of the 350°-550°F light oil were calculated from mass spectra. Liquid displacement chromatography on Florisil was used to determine the amount of polar material in the 550°-850°F heavy oil. 

Various procedures described by Crippen and Smith (5) are available for identifying components in a chromatogram. Because of the limitations mentioned above, the choice of method was restricted. Peak identifications for this sample relied on cleanup and preliminary separation by column adsorption chromatography with activated alumina and Florisil, use of the chlorine- and sulfur-specific microcoulometric detector, and parallel injections onto three or more columns containing liquid substrates varying widely in polarity. 

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