Fluorescence with petroleum ether

Subsequent to removal of fats by extraction with petroleum ether, and processing with ammonia, alkaloids of mate, cola, and cocoa were isolated by extraction with CHC13, and separated by thin layer chromatography. On UV irradiation, the alkaloids showed dark spots on a light fluorescent... 

A more comprehensive approach was reported in 1975 by Brabander and Verbeke (612). In this method, tissue samples were extracted with methanol and the acidified extract defatted with petroleum ether to be loaded onto a Dowex 50W-X8 anion-exchange resin. Following elution with aqueous methanol, the concentrated buffered extract was further defatted with diethyl ether. The sample was derivatized with 7-chloro-4-nitrobenzo-2-oxa-l,3-diazole (NBD-Cl) to be further spotted on a silica high-performance thin-layer chromatographic plate developed in two dimensions using chloroform/ethanol and chloroform/propionic acid consecutively as eluents. Detection of the propylthiouracil, phenylthiouracil, and tapazole residues was carried out on the basis of the fluorescence induction of the NBD derivatives of the drugs with an alkaline cysteine solution. 

An immediate color change to a very pale gold is observed. After S min the solution is evaporated to dryness with a rotary evaporator, and methanol (10 mL) is added to the residue to destroy any remaining boron tribromide. Purification of the product is accomplished by preparative scale TLC (see the footnote in the procedure in Section A) on fluorescent silica gel, eluting with petroleum ether (bp 30-60 Q. The complex [Os3H3(//3-CBr)(CO)9] (100mg, 90%) is obtained after extraction of the single colorless band with dichloromethane. 

This elegant system has been applied to the analysis of vegetable oils, after saponification and extraction with petroleum ether. Tocol was used as an internal standard. Examples of tocopherol profiles of vegetable oils are depicted in Fig. 11. There was a good agreement between the SEC results and those obtained by HPLC on the same column using fluorescence detection. Other investigators also accomplished a separation by SEC of the different E vitamers, e.g. in marine oil... 

C12-C18 soaps alkyl distribution Sewage and sewage sludge Sludge preliminary Soxhlet extraction with petroleum ether to remove lipids, addition of Ci7 internal standard, conversion to soluble salts, Soxhlet extraction with MeOH. Sewage no workup RP-HPLC of p-bromophenacyl bromide derivative-UV detection (254 nm), or 4-bromomethyl-7-methoxy coumarin-fluorescence detection (X xAem = 328/380 nm) 45,176,177... 

Compounds 1,2,3,5,10,11,12,13,14 were dissolved in EPIP (diethyl ether, petroleum ether, isopropanol 5 5 2)whereas compounds 4,6,7,8,9,15 were dissolved in THF-DE (tetrahydrofurane, diethyl ether 1 1). These solvent mixtures can be frozen as glassy samples at 77 K. The absorption spectra were recorded on a standard spectrophotometer SF-10 or Beckman-5270. The measurements of fluorescence excitation and emission spectra were made with the aid of a spectrofluorometer SLM-4800 with automatic correction of spectral response. Fluorescence lifetimes were measured with the aid of a pulse fluorometer PRA-3000. Magnetic circular dichroism (MCD) measurements were carried out in a 8 kG magnetic field using a JASCO J-20 circular dichrometer. Triplet state formation was observed for investigated compounds at the experimental set up, whose detailed description can be found in our paper (27). The optical experiments were carried out with a porphyrin concentration of 4.10- - 4.10 mol.l". In NMR investigations (Bruker WM-360) we used higher concentrations ( 5.10" raol.l ) and dried solvents (CDCl, C 2 and toluene-d0). 

Monitoring was carried out by extracting acidified samples with ethyl acetate and TLC [silica gel Macherey, Nagel Co. Polygram Sil G/UV 254", petroleum ether/ethyl acetate/acetic acid 99 50 1, visualization of spots by UV R, = 0.37 (spot shows strong blue fluorescence)]. 

Analyze the first crop of triphenylmethanol and the residue from the evaporation of the mother liquors by thin-layer chromatography. Dissolve equal quantities of the two solids (a few crystals) and also biphenyl in equal quantities of dichloromethane (1 or 2 drops). Using a microcapillary, spot equal quantities of material on silica gel TLC plates (Eastman No. 13181) and develop the plates in an appropriate solvent system. Try 1 3 dichloro-methane-petroleum ether first and adjust the relative quantities of solvent as needed. The spots can be seen by examining the TLC plate under a fluorescent lamp or by treating the TLC plate with iodine vapor. From this analysis decide how pure each of the solids is and whether it would be worthwhile to attempt to isolate more triphenylmethanol from the mother liquors. 

It is slightly soluble in water, forming a red solution with a marked green fluorescence. The compound dissolves in methyl alcohol, ethyl alcohol, acetone, and glacial acetic acid, but is insoluble in benzene, toluene, ether, and petroleum ether. In concentrated sulfuric acid it yields a yellow solution which does not fluoresce. Orndorff and... 

The best method for urinary estrogens of clinical importance is that devised by Brown (B20, B21). This depends on the modification of the Kober-Ittrich color reaction to provide an extremely sensitive fluorescence reaction (see also S2). Acid hydrolysis (15 minutes) is followed by either extraction (2X1 volume) evaporation to dryness a partition between petroleum ether-benzene and water (estriol) and 1.6% NaOH (estradiol, estrone). The two solutions are methylated (10 minutes) and extracted with ether the ether is evaporated, and the residues are run on alumina columns. In the original procedure the less specific and sensitive form of the Kober reaction required more extensive purification one technician could complete four estimations in 1.5-2 days. The new procedure enables four determinations to be made every 5-6 hours. An ultrarapid version of this method for specialized obstetric use has been devised by Gemzell and his group and will be published shortly. By this method, twelve samples can be measured in 3 hours by one technician. 

A mixture of 2 chloro 4,6,8-tripiperidinopyrimido[5,4-(/]pyrimidinc (4 g, 0.01 mol) and A-methylpiperazine (10 g, 0.1 mol) was refluxed for 6h. The excess /V-meth vlpiperazine was removed under vacuum (85-90 °C/ca. 15 Torr), and the residue was triturated with H20 and dried to give a yellow solid crude yield 4.7 g mp 132-140 C. Three recrystallizations from petroleum ether (bp 38-53°C) gave fluorescent-yellow crystals yield 3.6 g (72%) mp 141-143 CC. 

Figure 2. Photodecomposition of Aroclor 1254 in petroleum ether solutions irradiated with fluorescent sunlight lamps (borosilicate cells).

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