Florisil tubes

Sampling glass fiber filter with Florisil tubes... 

PCBs in air may be analyzed by NIOSH Method 5503. Using a personal sampling pump, 1 to 50 L air is passed though a 13 mm glass fiber filter and through a florisil column at a flow rate of 50 to 200 mL/min. A glass fiber filter is placed in a cassette that is connected to the florisil tube. The latter contains 100 and 550 mg florisil in the front and back sections of the tube, respectively. 

Atrazine Herbicides. The herbicides, atrazine and cyanazine, may be analyzed by HPLC. Samples collected as filter wipes (Whatman 41), on Florisil tubes, or in ethylene glycol impinger solutions have been analyzed. Florisil tubes and wipe samples are extracted with acetonitrile and the resulting extracts injected directly into the HPLC system. Ethylene glycol impinger solutions are extracted with chloroform, concentrated by evaporation, and taken up in acetonitrile and the resulting solution used for HPLC injection. HPLC analyses are achieved as follows ... 

Figure 8.4 Apparatus for sample preparation using physical separation. A - fractionation tube and trap for assisted distillation (A septum injector, B carrier gas inlet, C Florisil trap for collecting volatile pesticides) B, Shapiro-type freeze concentrator and C, apparatus for solvent sublation.

Alkylation of 1. To a mixture of the ester 1 (5 g, 25 mmol) and 6% of Aliquat 336 (715 mg, 1.5 mmol) was added t-BuOK (3.3 g, 25 mmol, 1 equiv.) under magnetic stilling over 15 min alkyl bromide (25 mmol, 1 equiv.) was then added slowly. The flask was left under the experimental conditions indicated in Table 1. Finally, the mixture was diluted with ethyl acetate (50 ml) and filtered on Florisil (10 g). The crude products were analysed by GC and characterised by MS and HNMR. 2-Alkylcyclohexanones. A mixture of lithium bromide (1.73 g, 20 mmol), tetrabutylammonium bromide (323 mg, 1 mmol), water (360 mm, 0.36 mL, 20 mmol) and ethyl l-alkyl-2-oxocyclohexanecarboxylate 2 (10 mmol) was placed in a Pyrex tube. The tube was then introduced into a Maxidigest MX 350 Prolabo microwave reactor fitted with a rotational system. Microwave irradiation was carried out for a suitable power and time (Table 2). An approximate final temperature was measured by introducing a digital thermometer at the end of irradiation. The mixture was cooled to ambient temperature. After elution with ethyl acetate (50 mL) and subsequent filtration on Florisil, organic products were analyzed by GC and finally purified by chromatography on silica gel (pentane-ethyl acetate, 95 5). 

A mixture of eugenol 1 (15 mmol), crushed potassium hydroxide or terbutoxide (33 mmol), the phase transfer catalyst (0.75 mmol) was placed either in a beaker in a domestic oven or in a Pyrex tube introduced into the Maxidigest MX 350 Prolabo microwave reactor filled with a rotational system. Microwave irradiation was carried out in the conditions described in Table 3 and 4. The mixture was cooled to ambient temperature. After elution with diethyl ether (50 mL) and subsequent filtration on Florisil, the organic products were analyzed by GC using an internal standard and characterized by 1H NMR spectroscopy by comparison with authentic samples. 

Collect the ACN in a PP tube. Add another 15 ml of ACN to sample residue and shake, centrifuge and elute through the above florisil/carbon column. Combine the 2 ACN eluates. Then elute with 5 ml methanol through the column. Combine ACN and methanol (total 50 ml) and blow it down to dryness under a gentle stream of nitrogen. Reconstitute the solvent with 1ml methanol and filter it through the nylon filter, prior to instrumental analysis. 

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. 

A solution of 5,5.5-trifluoro-l-phcnylpenta-1.3-diene (%mg, 0.48 mmol) and maleic anhydride (64 ing, 0.65 mmol) in benzene (5 mL) was heated in a scaled lube at 150 C for 24 h. The tube was then cooled and opened, and the conlenls were extracted with Et20. After evaporation of the solvent, the residue was separated by column chromatography (Florisil. hexane/CHjClj 1 1) to give the starling diene (58.6nig. 61 %) and the product yield 33.3 mg (23%). 

A Pyrex tube containing diphenyldiazomethane (1.94 g, 10 mmol) and freshly distilled cyclopenta-1,3-diene (25 mL) was immersed in an ice bath alongside a 450-W Hanovia well and irradiated for 4h at 0-5 °C. After concentration and collection of 1,1,2,2-tetraphenylethane (529 mg) and tetraphenylketazine (72 mg), the residue was chromatographed on a Florisil column packed with hexane to give cyclopentadiene dimer (2.25 g), a semisolid containing the product (625 mg), 1,1,2,2-tetraphenylethane 96 mg) and benzo-phenone (457 mg). Crystallization of the second fraction afforded 456 mg (20%) of the product mp... 

The analyses thus far have only been conducted with female pupae and are incomplete and the scheme of isolation is shown in Figure 3. The butanol phase which contained the free ecdysteroids was further fractionated by counter-current distribution (CCD) [60 transfers in a system of cyclohexane-butanol-water (4 6 10) with 10 ml of each phase]. The material from CCD tubes 23-42 was subjected to three Cie SEP-PAK fractionations (13). Quantitative RP-HPLC and radioassay analyses of fractions T and 5 resulting from using a SEP-PAK elution system as in Figure 3 yielded 200 Mg of labeled 20-hydroxyecdysone. The combined residues from CCD tubes 43-57 when fractionated over a Florisil SEP-PAK cartridge and chromatographed over 4 g of Silica gel yielded 22 pg of labeled ecdysone. 

Campins-Falco et al. (2008) Comunidad Valenciana Mussels, tellins Miniaturized MSPD-samples C18 phase-Florisil, in tube SPME LOD 0.05-0.6 ng/g dw Optimization of method HPLC-FLD... 

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