Florisil column cleanup

Florisil column cleanup. Prepare a Florisil column by placing a glass-wool plug in the bottom of a glass chromatography column. Slurry 15 g of Horisil with hexane-ethyl acetate (50 1, v/v) and transfer the slurry into the column. Rinse the walls of the column with hexane-ethyl acetate (50 1, v/v) and add approximately 2g of sodium sulfate to the top of the Horisil column. Drain the solvent to the top of the sodium sulfate layer. 

EPA. 1986h. Method 3620. Florisil column cleanup. In Test methods for evaluating solid waste. Vol IB, Laboratory manual, Physical/chemical methods. SW846. U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, Washington DC, 3rd ed. 

ACN/MeOH extn, alumina/Florisil column cleanup, liq-liq partn, online trace enrichment on Bondapak Cis/ Corasil, 37-50... 

Elution Patterns for Pesticides in Florisil Column Cleanup Table 2.20.3... 

A 1-L aliquot, or any appropriate volume of accurately measured aqueous sample, is extracted with methylene chloride by liquid-liquid extraction. The extract is concentrated to 1 mL or any small volume on a Kudema-Danish setup. A florisil column cleanup may be necessary if the sample is dirty, or the presence of interferences is known or suspected or if A-nitrosodiphenylaminc is to be determined. 

Prior to florisil column cleanup, the column should be preeluted with ether-pentane mixture (15 85 v/v). The extract is then transferred onto the column and the column is eluted again to remove ary diphenylamine contaminant. The analytes A-mtrosodnnethylanune, A-mtrosodi-n-propylamine, and A-nitrosodiphc-nylamine, and other similar aliphatic and aromatic nitrosamines are desorbed from the column with acetone-ether mixture (5 95 v/v). This fraction is then concentrated for analysis. 

Sediment Supercritical fluid extraction mini-Florisil column cleanup sulfur removal HRGC/ECD confirmation by MS No data 90 Lee and Peart 1994... 

Mammal blubber Sample ground solvent extraction micro-Florisil column cleanup dual column HRGC/ECD 30 pg/kg 95.2 (mean) Newman et al. 1994... 

PAM 304 Fatty foods, animal tissue, fatty fish El. Extraction of fat with sodium. sulfaie, petroleum ether Cl. Acetonitrilc-pretroleum ether partitionii, Florisil column cleanup with three mixed ether eluani.s DG12/14 for residues with phosphorus... 

C4. Acetonitrile-petroleum ether partiiioning, Florisil column cleanup, petroleum ether and three methylene chloride eluants ... 

Technique a scientific principle or specific operation, (e.g., gas chromatography-electron-capture detector, GC ECD, Florisil column cleanup or so-called Webb and McCall quantitation. 

Heikes, D.L. Procedure for supercritical fluid extraction and gas chromatographic determination of chlorinated fatty acid bleaching adducts in flour and flour-containing food items utilizing acid hydrolysis-methylation and Florisil column cleanup techniques. J. Agric. Food Chem. 1993, 41 (11), 2034-2037. 

A homogenized sample of cereals, vegetables, fruits or potatoes (10-20 g) is extracted with an organic solvent such as acetone and methanol. After filtration, the extract is concentrated to about 20 mL by rotary evaporation below 40 °C. The residue is transferred with 5% sodium chloride (NaCl) aqueous solution and partitioned twice with n-hexane. The n-hexane extracts are dried with anhydrous sodium sulfate and subjected to a Florisil column chromatographic cleanup procedure. The eluate from the Horisil column is concentrated to dryness and the residue is dissolved in an appropriate amount of acetone for analysis by GC/NPD. ... 

Note each lot of Florisil must be checked for acceptable recovery of flumioxazin prior to initiating the column cleanup procedure. Adjust elution volumes and/or the solvent mixture as necessary to achieve >90% recovery for this step. Sample cleanup with Florisil may not be required for some water samples. 

Three standardized methods were found in the Official Methods ofAnalysis of the Association of Official Analytical Chemists (AOAC 1990). The first of these methods is based on the extraction of crops (kale, endive, carrots, lettuce, apples, potatoes, and strawberries) with ethyl acetate and isolation of the residue followed by a sweep codistillation cleanup prior to GC/thermionic detection (Method 968.24). The second of these methods utilizes Florisil column chromatography clean-up followed by GC/FPD (Method 970.53). In the third method (Method 970.52), the sample is extracted with acetonitrile, and the residue is partitioned into petroleum ether followed by Florisil clean-up and GC/KC1 thermionic detection. Identifications are based on combinations of gas, thin-layer, and paper chromatography. The recovery for diazinon in this method is stated to be greater than 80% no data on limits of detection were given. 

Phthalate Esters (Method 606). These compounds are extracted with methylene chloride, concentrated, and solvent exchanged to hexane for Florisil or aluminum oxide column cleanup and EC-GC determination by using a mixed phase columnn of 1.5 SP-2250 and 1.95 SP-2401. This method is essentially the same as that for or-ganochlorine pesticides. 

Nitrosamines (Method 607). The nitrosamines are extracted with methylene chloride, treated with HC1, concentrated, and solvent exchanged to methanol for direct nitrogen-phosphorus or thermal energy analyzer (TEA) detection. Provision is made for Florisil or aluminum oxide column cleanup prior to GC analysis. The GC column liquid phase is 10 Carbowax 20 M plus 2 KOH. N-Nitrosodiphenylamine thermally degrades to diphenylamine in the GC and is measured as diphenylamine after prior removal of any diphenylamine occurring, as... 

The RP-HPLC system was tested on the fractionation of OPPs and OCPs, from edible fats and oils of both animal and vegetal origin. When acetonitrile was used, the most polar OPPs eluted rapidly but tailed on this column, whereas the relatively nonpolar OCPs were retained the longest. Additional cleanup on miniature Florisil columns is required for the dirtier samples. A UV detector was used to determine the elution patterns of standards (78). The same system was used for the fractionation of OPP residues in processed bay foods prior to the final determination by GC without further cleanup but using a MS detector (66). 

The solvent extract should be subjected to one or more cleanup steps for the removal of interfering substances. The presence of phthalate esters, sulfur, or other chlorinated compounds can mask pesticide peaks. The extract should, therefore, be cleaned up from the interfering substances using a florisil column or by gel permeation chromatography (see Chapter 1.5). The distribution patterns for the pesticides in the florisil column fractions are presented in Table 2.20.2. 

To eliminate the interference effect of other contaminants and for dirty sample extracts, cleanup may become necessary. The extract is either passed through a florisil column or an alumina column and the phthalate esters are eluted with ether-hexane mixture (20% ethyl ether in hexane, v/v). 

Determination of the intact CW agents in urine or blood may proceed by the methods commonly applied to water samples. Extraction with an organic solvent and subsequent cleanup with a Florisil column is a well-established procedure. Rather volatile, scheduled compounds can often be successfully recovered and purified from biological materials by means of dynamic headspace stripping and subsequent adsorption on Tenax tubes these tubes are then subjected to GC/MS analysis. 

Koistinen et al. [98], who studied the induction of EROD activity of 29 PCDE congeners in vitro using H4IIE rat hepatoma cells, have reported that PCDEs are inactive as inducers of EROD. A similar type of activity as that reported by Howie et al. [88] was only seen with PCDE congeners before cleanup by Florisil column chromatography. After the removal of PCDD and PCDF impurities using Florisil the activity was lost, except for PCDE 156 which was a weak inducer (TEF 1.2 x 10-5). It is possible that effects such as chloroacne reported for higher chlorinated PCDEs [12], could be due to toxic PCDF impurities. 2,3,7,8-Substituted PCDFs have been measured at ng ml-1 levels in 10 pg ml-1 PCDE solutions [98]. 

In addition to lipid removal, Florisil column chromatography can be used for chromatographic cleanup and to separate PCDEs from other compounds such as PCBs, PCDDs, and PCDFs. Florisil has been used activated and after deactivation with water. An activated Florisil column has been reported to separate PCDEs... 

Coburn and Comba [115] used activated Florisil (30 g column) and eluted PCDEs with 6% ethyl ether in hexane (200 ml) after they had collected PCBs with hexane (200 ml). Birkholz et al. [120] used a 0.8% deactivated Florisil column (12 g) as an additional cleanup after multisilica column chromatography. PCDEs and PCBs were eluted with 100 ml of hexane from Florisil. PCDEs were then separated from PCBs using a basic alumina column. Newsome and Shields [126] used Florisil (12 g column) deactivated with 2% water and eluted PCDEs with hexane (85 ml) for further cleanup by HPLC using acetonitrile as an eluent. Stafford [121] has also used deactivated Florisil. 

Koistinen et al. [58] have applied a Florisil cleanup which uses a partially deactivated (1.25%) Florisil microcolumn (1 g) to separate PCDEs from PCDDs and PCDFs in abiota and biota extracts [33,57,113,114,123-125]. After sulfuric acid cleanup, PCDEs are eluted through a Florisil column together with PCBs using hexane (15 ml). PCDDs and PCDFs are retained in the column and can be eluted with dichloromethane (12 ml). 

Tomy et al. [ 14] extracted PCAs from fish and sediments by using DCM extraction, lipid removal by SX-3 Biobeads gel permeation chromatography (GPC) [53], and cleanup with Florisil column chromatography. Fractionation on Florisil was achieved by eluting with hexane (FI), which eluted all the PCBs, chlorinated benzenes, 4,4 -DDE, then with (15 85) DCM/hexane (F2), and finally with (1 1) DCM/hexane (F3). Fractions F2 and F3 contained PCAs along with 4,4 -DDT, toxaphene, cis- and frans-chlordane and other more polar organics, such as heptachlor epoxide and dieldrin. The mean percentage recovery of PCAs for this method was 85 %. 

Adipose tissue Extraction with acetone/hexane fractionation by GPC cleanup on Florisil column Two dimensional HRGC/MS No data >80 at 10-500 ng/g Le Bel and Williams 1986... 

Human hair (congener specific) Ultrasonic extraction with acetone/hexane wash of extract with concentrated sulfuric acid and alkaline hydrolysis cleanup on Florisil column fractionation on carbon column HRGC/ECD No data No data Zupancic-Kralj et al. 1992... 

Rain water (congener specific) Passage through filter and XAD-2 resin solvent extraction cleanup on Florisil column 2-dimensional HRGC/ECD <1-30 pg/L 79-83 Leister and Baker 1994... 

Waste water Extraction with methylene chloride exchange to hexane cleanup on Florisil column removal of elemental sulfur if necessary GC/ECD 0.065 pg/L (PCB-1242) 88-96 at 25-110 pg/L EPA 1982a, 1988b (method 608)... 

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