Cleanup florisil

OCPs and PCBs LLE hexane-acetonitrile, cleanup Florisil, RP-HPLC C18, derivatization to p.p-DCBP, UV 205 nm 1 fig-1 mg/g 81.6 — 62... 

The primary method for detecting methyl parathion and metabolites in biological tissues is gas chromatography (GC) coupled with electron capture (BCD), flame photometric (FPD), or flame ionization detection (FID). Sample preparation for methyl parathion analysis routinely involves extraction with an organic solvent (e g., acetone or benzene), centrifugation, concentration, and re suspension in a suitable solvent prior to GC analysis. For low concentrations of methyl parathion, further cleanup procedures, such as column chromatography on silica gel or Florisil are required. 

Air Collect on hexylene glycol-alumina adsorbent sampler extract cleanup with Florisil GC/FPD 0.1 ng/m 53.4 Stanley et al. 1971... 

HPLC has been recommended as a cleanup and fiactionation procedure for food samples prior to analysis by GC/ECD (Gillespie and Walters 1986). The advantages over the AOAC-recommended Florisil colunrn are that it is faster, requires less solvent, and gives better resolution. HPLC coupled with various detectors MS, MS/MS, UV/electrochemical detector, or UV/polarographic detection has been tested as a rapid, simplified separation and detection system to replace GC (Betowski and Jones 1988 Clark et al. 1985 Koen and Huber 1970). Recoveries, detection limits, and precisions were generally good, but further work is needed before the techniques are adopted for general use. 

For multi-analyte and/or multi-matrix methods, it is not possible to validate a method for all combinations of analyte, concentration and type of sample matrix that may be encountered in subsequent use of the method. On the other hand, the standards EN1528 andEN 12393 consist of a range of old multi-residue methods. The working principles of these methods are accepted not only in Europe, but all over the world. Most often these methods are based on extractions with acetone, acetonitrile, ethyl acetate or n-hexane. Subsequent cleanup steps are based on solvent partition steps and size exclusion or adsorption chromatography on Florisil, silica gel or alumina. Each solvent and each cleanup step has been successfully applied to hundreds of pesticides and tested in countless method validation studies. The selectivity and sensitivity of GC combined with electron capture, nitrogen-phosphorus, flame photometric or mass spectrometric detectors for a large number of pesticides are acceptable. 

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. 

The eluate from the Cig cartridge is concentrated by rotary evaporation and the residue is dissolved in n-hexane and then subjected to a cleanup procedure using a Florisil cartridge. The eluate is dried and analyzed by gas chromatography (GC) with nitrogen-phosphorus detection (NPD). 

Second cleanup Transfer the n-hexane solution into a Florisil cartridge preconditioned with 5 mL of n-hexane and elute thenylchlor with 10 mL of acetone-n-hexane (1 9, v/v). Concentrate the eluate to dryness by rotary evaporation at 40 °C and dissolve the residue in 5 ml of acetone for GC analysis. 

Prior to the development of modern SPE formats, liquid-solid partitioning with charcoal, silica, Florisil, and/or alumina was common to aid in the removal of lipids in the determination of nonpolar pesticides, but these sorbents are less useful in the cleanup of semi-polar and polar pesticides owing to the large elution volumes needed. Applications of modern SPE are discussed in Section 3.2. 

The development of solid-phase extraction (SPE) absorbents such as silica gel, alumina and Florisil tremendously aided in the purification or cleanup of pesticide residues from water. 

For imidacloprid, the combined Altrates are concentrated with a rotary evaporator. The Anal residue is dissolved in 5 mL of n-hexane and applied to a silica gel cartridge, preconditioned with 5 mL of n-hexane. The n-hexane solution is transferred into the carAidge, which is rinsed with 5mL of n-hexane-ethyl acetate (1 1, v/v) and eluted with 8 mL of ethyl acetate. Further cleanup could be carried out using a Florisil carAidge, if needed. The imidacloprid residue in 4 mL of n-hexane-acetone (13 7, v/v) is eluted with 8 mL of n-hexane-acetone (2 3, v/v). The eluate is concentrated under vacuum on a rotary evaporator at 40 °C. The residue obtained is dissolved in a suitable volume of water-acetoniAile (4 1, v/v) and analyzed by HPLC (270 nm). ... 

The sample is homogenized with acetonitrile. An aliquot of the extract is evaporated to dryness and the residual material is dissolved in ethyl acetate-toluene (3 1, v/v), and subjected to cleanup by gel permeation chromatography (GPC). After GPC, the sample is subjected to an alumina and Florisil SPE cleanup procedure. The concentrated eluate is analysed by gas chromatography/thermionic nitrogen-specific detection (GC/TSD). 

Soil sample is extracted with a mixture of methanol and 0.1 M ammonium chloride. Acetamiprid, IM-1-2 and IM-1-4 residues are extracted with dichloromethane under alkaline conditions. After adding diethylene glycol, dichloromethane in the extract is removed by rotary evaporation, and the residue is subjected to a cleanup procedure using Florisil PR column chromatography and then with a packed Extrelut 20 column. 

Macerated plant material is homogenized with a mixture of methanol and 1.2N hydrochloric acid (HCl) in water (4 1, v/v) and then with methanol. An internal standard solution is added to the filtrate and the filtrate is adjusted to a constant volume. A portion of the filtrate is rotary evaporated to dryness and hexane is added to the extract before a Florisil cleanup procedure is performed. The extract is dissolved in toluene for analysis by GC/MS in the negative chemical ionization (NCI) mode. 

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. 

Water/waste water Extract with methylene chloride exchange to hexane Florisil cleanup, if required GC/ECD 0.03 pg/L 99 EPA 1982... 

Food (fish, milk, butter, com oil) Extract with acetonitrile cleanup with Florisil elute with petroleum ether and ethyl ether/petroleum ether GC/ECD No data 80 Yurawecz an Puma 1986... 

Florisil Cleanup of chlorinated hydrocarbons, nitrogen, and aromatic compounds Has basic properties and may not be compatible with acids... 

The basic technique of removing undesired components from a solution with the help of solids has been used for sample cleanup for a long time. The recoveries from a quick cleanup for waste solvents based on a sample filtration through a Florisil and sodium sulfate column are given in Table 2.3. It can be seen from the data in this table that a large number of pesticides are retained by Florisil. These can be recovered for appropriate analysis. 

Lopez-Avila V, Milanes J, Dodhiwala NS, et al. 1989. Cleanup of environmental sample extracts using florisil solid-phase extraction cartridges. J Chromatogr Sci 27(5) 209-220. 

Human milk Solvent extraction cleanup with sulfuric acid, Florisil GC/ECD 5 ppb >80 Jan 1983... 

P14 The most common cleanup methods are as follows shaking the extract with concentrated sulfuric acid, Florisil, alumina,and silica gel and using size exclusion chromatography (SEC). (From Llompart et ah, 2001)... 

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