Florisil Column Chromatography Research Articles

High Performance Liquid Chromatographic Determination of Nifurpirinol in Fish

A method is described for the quantitative determination of nifurpirinol (NFP) in fish by high performance liquid chromatography. Samples were mixed with anhydrous sodium sulfate and extracted with dichloromethane. The extract was cleaned up by florisil column chromatography. Concentration of the acetone eluate yielded a residue, which was dissolved in methanol containing 2-nitro-p-cresol as an internal standard. NFP was separated on a column packed with LiChrosorb RP-18, 5μm, (4mm×150mm) by using 2.5×10-5v/v% acetic acid in acetonitrile-water (45:55, v/v%) as the mobile phase, with detection at 390nm. The recoveries of NFP added to fish were in the range from 81.8% to 93.9% with an average of 84.8% at levels from 0.1ppm to 0.5ppm. The minimum detectable amount of NFP was 1.25ng. The calibration curve was linear over the range from 2.5ng to 150ng.

Simultaneous Determination of Nitrite and Nitrate in Foods by Gas Liquid Chromatography

A simple and practical method for the simultaneous determinations of nitrite and nitrate in various foods is described. It is based on the formation of tetrazolophthalazine, by the reaction of nitrite and hydralazine in an acidic medium (pH 1.0-3.0) at 70°C for 10min, and the formation of 4-nitro-2-sec-butylphenol, by the reaction of nitrate and 2-sec-butylphenol in aqueous (5+7) sulfuric acid at room temperature for 15min and subsequent pentafluorobenzoylation to form the pentafluorobenzyl ester of 4-nitro-2-sec-butylphenol in the alkaline range. The two products were simultaneously analyzed by means of gas liquid chromatography with a flame-ionization detector and a column of 5% OV-17 on Chromosorb W, HP; the detection limits are 0.05μg/ml for nitrite and 0.10μg/ml for nitrate.For the determinations of nitrite and nitrate in foods, clean-up of crude extracts by florisil column chromatography and by addition of silver sulfate allows the satisfactory elimination of interfering compounds. The recoveries from several foods were 95.1-98.1 for nitrite and 95.7-98.3 for nitrate, and the standard deviations for the whole procedure (28 determinations) were 1.1% for nitrite and 1.0% for nitrate.

Improved 4-Aminoantipyrine Colorimetry for Detection of Residual Hydrogen Peroxide in Noodles, Fish Paste, Dried Fish, and Herring Roe

Improved 4-aminoantipyrine (4-AA) colorimetry was developed for the detection of minute quantities of residual hydrogen peroxide in several kinds of food. Hydrogen peroxide in the sample was stabilized with potassium bromate and extracted with cold methanol. The methanol extract was diluted with phosphate buffer, protein was eliminated with zinc sulfate, and the extract was reacted with phenol, 4-AA, and peroxidase to the stable quinoneimine dye. The weak color solution was purified with Florisil column chromatography, concentrated, and determined by colorimetry. Recoveries of hydrogen peroxide from samples fortified at 0.5, 2, and 10 ppm ranged from 70.7 +/- 8.9 to 98. 5 +/- 1.2%. Color development was linear with amount of H2O2 from 0.5 to 20 micrograms, corresponding to 0.05-2 ppm in samples.

Column chromatography fractionation of complex waste water sample extracts for measurement of ppt levels of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin

AbstractThe novel application of azulene as a visual monitor of column chromatography performance during fractionation of complex waste water extracts for measurement of 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) at part‐per‐trillion concentrations is described. TCDD elutes directly behind azulene, the blue visual aid, in the 6% ethyl ether/hexane fraction during Florisil column chromatography.

Application of Azulene as Visual Aid to Monitor Column Chromatographic Fractionation of Samples for Pesticide and Polychlorinated Biphenyl Determination

Abstract Environmental samples are cleaned up by Florisil column chromatography, using azulene as a visual aid to monitor column performance. Azulene migrates as a blue band in the 6% ethyl ether-hexane fraction, and the gas chromatograph electron capture detector (GC-ECD) is nonresponsive at the use concentration. This method complements the standardization of Florisil columns by weight adjustment based on adsorption of lauric acid. Spiking of sample with azulene provides a convenient real-time monitor for column channeling, mistakes in polarity of mobile phases, particular sample composition, column overloading, and dynamic changes in the adsorptivity of the stationary phase between lauric acid calibration and use. Using this visual aid, the analyst is alerted to unexpected column behaviors. Normally, polychlorinated biphenyls (PCBs) elute in the 6% fraction, in front of the blue indicator. Experiences with azulene and industrial effluent samples demonstrated that PCBs can elute in the 100% hexane fraction. GC-ECD analysis of the hexane eluate revealed a PCB characteristic chromatogram, not observed with the original extract. Thus, monitoring column performance avoided reporting a false negative result, i.e., no PCBs in the 6% ethyl ether-hexane fraction.

Analytical Method for Diphenyl Ether Herbicides in Fish and Shellfish

The determination of diphenyl ether herbicides, NIP, CNP, chlomethoxynil and TCNP, was achieved according to the procedure for the determination of organochlorine pesticides, which consists of acetonitrile extraction and clean-up by silver nitrate-coated Florisil column chromatography.The homogenized sample is extracted 3 times with acetonitrile. The extract is diluted with water and re-extracted with n-hexane. After concentration, the n-hexane layer is subjected to silver nitrate-coated Florisil column chromatography. The 2% ethylacetate/n-hexane eluate is concentrated for ECD/GC analysis. Satisfactory gas chromatograms were obtained for most samples.The average recoveries throughout the procedure were 98% (NIP), 97% (CNP), 91% (chlomethoxynil) and 95% (TCNP).

Identification of CNP, Chlomethoxynil and TCNP in Corbicula

Three unknown peaks were found on ECD gaschromatograms of n-hexane extracts from corbicula, appearing closely after organochlorine pesticides.These three substances were purified by silver nitrate-coated florisil column chromatography and high performance liquid chromatography. Two of them were identified as CNP (2, 4, 6-trichrophenyl-4′-nitrophenyl ether) and chlomethoxynil (2, 4-dichlorophenyl-3′-methoxy 4′-nitrophenyl ether) which are widely used as rice paddy herbicides in Japan.The other constituent was suspected from its mass spectrum to be a diphenyl ether derivative with four chlorine atoms and a nitro group. Later, it was identified as a TCNP (2, 3, 4, 6-tetrachlorophenyl-4′-nitrophenyl ether), as a result of two synthetic reactions; 1) chlorination of CNP and 2) a coupling reaction on 2, 3, 4, 6-tetrachlorophenol and 1-fluoro-4-nitrobenzene.TCNP is present in commercial CNP herbicide, and is presumably a byproduct of CNP synthesis.

Gas Chromatographic Determination of Fluridone Aquatic Herbicide and Its Major Metabolite in Fish

A gas-liquid chromatographic (GLC) method is described for determining residues of the aquatic herbicide fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone) and its major metabolite (1-methyl-3-(4-hydroxyphenyl)-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone) in fish. Both compounds are extracted from fish tissue with methanol, and the extracts are subjected to acidic hydrolysis to release conjugated forms of fluridone and the metabolite. After purification by liquid-liquid partitioning, sample extracts are reacted with methyl iodide to methylate the metabolite, and then both fluridone and the metabolite are brominated with phosphorus tribromide. After purification by Florisil column chromatography, the derivatives are separated and measured by electron capture GLC. The method is capable of determining approximately 0.01 ppm of both compounds in fish, and recoveries have averaged 84 +/- 14.7% for fluridone and 83 +/- 13.4% for the metabolite.

Gas-Liquid Chromatographic Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Human Milk

A method for the detection of organochlorine pesticides and polychlorinated biphenyls (PCBs) in human milk is described. The method involves quantitative extraction of human milk with acetone and hexane. The pesticide and PCB residues are extracted from the milk fat with acetonitrile (ACN) and then partitioned back into hexane by aqueous dilution of the ACN extract. The ACN partitioning is followed by cleanup with Florisil column chromatography, eluting with 6 and 15% mixtures of ethyl ether-hexane. The 6% eluate is concentrated and transferred to a silicic acid column for separation of PCBs from pesticide residues. Compounds are quantitated by gas-liquid chromatography. Recovery studies demonstrated that the procedure provides 68-103% recovery for pesticides and PCBs.

Isolation of six unconjugated pteridines from soybean (Glycin max L. Tsurunoko) seeds.

Six unconjugated pteridines stored in soybean seeds were extracted with acid and isolated with a FLorisil column and reversed-phase high-performance liquid chromatography (HPLC). They were identified by HPLC, TLC, and fluorescence spectra to be 6-carboxypterin, erythro-neopterin, threo-neopterin, isoxanthopterin, 6-hydroxymethylpterin, and pterin. They were eluted in that order on HPLC. A much higher density of the pteridines, excepting isoxanthopterin, was found in the axis than in the cotyledon after a 6-imbibition.

Photoisomerization of a Moth-proofing Agent, Dieldrin to Photodieldrin in Wool

Photodieldrin formed by photoisomerization from dieldrin in wool was investigated. Photodieldrin was extracted by refluxing in methanol, purified by Florisil column chromatography after methanol was evaporated, and determined by gas chromatography with 63Ni-ECD. The recovery of photodieldrin from wool and woollen sweaters was 96% and 97% for 1 ppm, and 101% and 101% for 10 ppm, respectively. The detection limit was 0.05 ppm. The ratio of photodieldrin to dieldrin in wool irradiated for 3 hr in the light, increased to more than 10%, and were 0.2%, 11.5%, and 17.5% for 6 hr in 300-600 lux, 4000-16000 lux, and 20000-86000 lux, respectively. The photodieldrin concentration in 5 kinds of commercial wool was 0.12-0.45 ppm and the ratio of photodieldrin to dieldrin was 0.092-1.1%.

Biochemical studies on naturally occurring pteridines. Part VIII. Isolation and identification of Crithidia factors from Bacillus cereus IFO 3131.

Bacillus cereus IFO 3131 produces the largest amount of Crithidia factors of 27 bacterial species tested (J. Bacteriol., 104, 197, 1970). The factors in the culture fluid and cell were isolated with a Florisil column and reversed-phase high-performance liquid chromatography (HPLC). They were identified by HPLC, fluorescence and ultraviolet spectra, thin-layer chromatography and bioassay. The major factor in the cell was d-erythro-neopterin and that in fluid was 6-hydroxymethylpterin and pterin.

Separation and quantitation of 3,3',4,4'-tetrachlorobiphenyl and 3,3',4,4',5,5'-hexachlorobiphenyl in aroclors using florisil column chromatography and gas-liquid chromatography.

Separation and Quantitation of 3,3',4,4'-Tetrachlorobiphenyl and 3,3',4,4',5,5'-Hexachlorobiphenyl in Aroclors Using Florisil Column Chromatography and Gas-Liquid Chromatography LaVerne R. Kamops, William J. Trotter, Susan J. Young, Audrey C. Smith, John A. G. Roach, and Samuel W. Page Division of Chemistry and Physics, Food and Drug Administration, U.S. Department of Health, Education, and Welfare, Washington, DC 20204

Consecutive analysis of sphingoglycolipids on the basis of sugar and ceramide moieties by high performance liquid chromatography.

A quantitative consecutive method was developed for analysis of sphingoglycolipids in biological materials by high performance liquid chromatography (HPLC). Crude lipid extracts were separated into neutral and acidic fractions on a DEAE-Sephadex column. Glycolipid fractions were obtained by acetylation and Florisil column chromatography, and the acetylated glycolipids were N-p-nitrobenzoylated by treatment with p-nitrobenzoyl chloride in pyridine at 60 degrees C for 6 h. Excess reagent and by-products were removed by solvent partition and gel filtration. The glycolipid derivatives were analyzed by their absorption at 254 nm on Zorbax SIL, a silica gel column, with a gradient of 0.5--7% isopropanol in hexane-chloroform (2 : 1, v/v) at a flow rate of 0.5 ml/min. The detector response was linear with up to 60 nmol of injected glycolipids. The practical lower limit of detection was about 50 pmol. The derivatives were separated on the basis of their sugar chains. Effluents corresponding to each peak were collected and analyzed further on the basis of their lipid portion on mu-Bondapak C18, a reversed phase column. This combined procedure was applied to the analysis of erythrocyte glycolipids. Samples containing as little as 20 micrograms of glycolipids could be analyzed by this method.

Determination of Chlorinated Pesticide Residues in Foods. III. Simultaneous Analysis of Chlorinated Pesticide and Phthalate Ester Residues by Using AgNO3-Coated Florisil Column Chromatography for Cleanup of Various Samples

A simplified method suitable for simultaneous analysis of chlorinated pesticide and phthalate ester residues in various foods was developed. Chemical residues were quantitatively extracted from fatty and vegetable samples with acetonitrile as follows: Chemical standard in 0.5 mL ethanol solution was added to 10 g homogenized sample. After 3 hr, pork and beef were extracted 3 times with 20 mL portions of acetonitrile. The acetonitrile layers were diluted with water and extracted with n-hexane. Rice samples were combined with 10 mL water, 5 mL acetonitrile and 1 mL ethanol and extracted 3 times with 20 mL portions of n-hexane. The n-hexane concentrate from each sample was submitted to AgNO3-coated Florisil column chromatography. The AgNO3 coating adequately adsorbed interfering coextractives. Extracts of fish and vegetable samples were separated into 2 fractions by the above column chromatography. Supplemental cleanup procedures were also developed to accurately determine phthalate esters eluted in the second fraction. Satisfactory gas chromatograms were obtained for most samples.

Qualitative and quantitative changes in sterol lipids of cotyledons of germinating soybeans.

Soybean seedlings were grown at 28°C in the dark or the light for 12 days, and four classes of sterol lipids, sterol esters (SE), free sterols (St), acylated steryl glycosides (ASG) and steryl glycosides (SG), were isolated from the cotyledons by solvent extractions, Florisil column chromatography, and thin-layer chromatography (TLC), successively. Each sterol lipid (SE, ASG and SG) obtained was hydrolyzed and then separately divided into sterol, fatty acid and/ or sugar fractions. The hydrolysates and St were analyzed mainly by gas-liquid chromatography (GLC).Under the two conditions tested, the main sterol lipid class was St during germination, the minor one being SG. With the progress of germination, St and ASG decreased under both conditions tested, whereas SE and SG increased, especially SE in the light-grown seedlings. The changing patterns of sterol and sugar compositions of ASG resembled those of SG, but those of fatty acid composition differed between SE and ASG. In general, the changes in fatty ...

Studies on Residues of Synthetic Antibacterials in Livestock Products (I)

Extraction technique and determination method of 3, 5-dinitro-o-toluamide (zoalene) were described in this paper.The mixture of sample and anhydrous sodium sulfate was ground to fine powder by a homogenizer. The mixture was packed in a glass column of 38mm in diameter tightly.As eluting agent acetonitrile was used. Zoalene was eluted efficiently by the column chromatography, and after clean up it was treated by florisil column chromatography, condensate of eluent was made to react with heptafluoro-n-butyric anhydride. The determination was performed by ECD gas chromatography on the solution of reaction product. A linear calibration curve was obtained in range of 0.1μg/ml to 1.0μg/ml of zoalene. The lower limit of the sample size of zoalene for identification was 0.03ng.

Studies on Environmental Pollution by Chemical Substances. II. Determination of Aromatic Nitro Compounds in River and Sea Water

An analytical method for aromatic nitro compounds, such as nitrobenzene, o-, m-, and p-nitrotoluene, o-, m-, and p-nitroanisole, o-, and m-dinitrobenzene, and 2, 4, 2, 6-, and 3, 4-dinitrotoluene, in river and sea water is described. One liter of sample water was extracted with benzene in the presence of hydrochrolic acid. The extract was dehydrated and concentrated to 10 ml by a Kuderna-Danish (K. D.) evaporative concentrator. The extract was cleaned up by a Florisil column chromatography, and the components were eluted with benzene-ether (98 : 2, v/v). The eluate was concentrated to 10 ml and then quantified by a gas chromatograph (GC) with an electron capture detector (3H). A 5 ml portion of the solution was concentrated to 0.1 ml by the micro-K. D. evaporative concentrator and then qualified by a gas chromatograph-mass spectrometer (GC-MS) with a multiple ion detector. The recovery by this procedure was 86-99%, and as little as 0.025 to 0.25 ppb of the aromatic nitro compounds was able to be determined. The samples were obtained from the mouths of six rivers in Kanagawa Prefecture and the Tokyo Bay. Nitrobenzene was found in all of the samples and their content was 0.16-0.99 ppb. o-Nitroanisole (0.68 ppb) was detected in the water of the Tsurumi River in Yokohama City.

Studies on Mycotoxins in Foods (VIII)

An analytical procedure was investigated for the quantitative determination of several trichothecene mycotoxins in foods by gas chromatography.The presented method was composed as follows: The trichothecene mycotoxins were extracted from the sample with methanol. Concentrated extract was added on the Amberlite XAD-2 column, subsequently Florisil column chromatography was carried. The eluate was concentrated to dryness and 0.5ml of sililating reagent was added to the residue. Sililating reagent was prepared by mixing TSIM, TMCS, and chloroform in the volume ratio (1:0.2:9). TMS derivatives of trichothecene mycotoxins were determined by gas chromatography using a hydrogen flame ionization detector.Five trichothecene mycotoxins (nivalenol, deoxynivalenol, fusarenon-X, diacetoxyscirpenol and T-2 toxin) were recovered at 68-101% from 4 sample (barey, wheat, corn and rice) added these mycotoxins at the 1.0ppm level and the detection limit by the proposed method was 0.1ppm.As the results of the survey of 42 commercial foods, trichothecene mycotoxins were not detected.The presented method was found to be sufficiently satisfactory for the quantitative determination of trichothecene mycotoxins in foods.

Structural studies on branched fucosphingolipids of hog gastric mucosa

A structural studies have been performed on new complex glycolipids extracted from hog gastric mucosa by 0.4 M sodium acetate in methanol-chloroform-water, and which were purified to homogeneity by DEAE-Sephadex and Florisil column chromatography and by preparative thin-layer chromatography in three solvent systems. Five branched fucolipids have been purified from this extract, three of which have been characterized previously [1] and remaining two were subject of this investigations. Based on the results of partial acid hydrolases, oxidation with periodate and chromium trioxide, permethylation and serological activities following structures were proposed: Fucolipid IVa ▪