scholarly journals Determination of several fullerenes in sewage water by LC HR-MS using atmospheric pressure photoionisation

2015 ◽  
Vol 2 (2) ◽  
pp. 167-176 ◽  
Author(s):  
E. Emke ◽  
J. Sanchís ◽  
M. Farré ◽  
P. S. Bäuerlein ◽  
P. de Voogt
Keyword(s):  
Atmospheric Pressure ◽  
Sewage Water ◽  
Normal Phase ◽  
Phase Column

By using a normal phase column, this method is capable of unambiguously identifying and quantifying (functionalised) fullerenes in sewage water.

scholarly journals Determination of gangliosides as 2,4-dinitrophenylhydrazides by high-performance liquid chromatography

1986 ◽  
Vol 235 (3) ◽  
pp. 755-761 ◽  
Author(s):  
K Miyazaki ◽  
N Okamura ◽  
Y Kishimoto ◽  
Y C Lee
Keyword(s):  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Normal Phase ◽  
Water Soluble ◽  
Acid System ◽  
Total Lipids ◽  
Acetylneuraminic Acid ◽  
Chloroform Methanol ◽  
Phase Column

A specific, sensitive and easily performed method for the determination of gangliosides in tissue was developed. After removal of water-soluble compounds, total lipids were extracted from tissue and then treated with 2,4-dinitrophenylhydrazine hydrochloride and dicyclohexylcarbodi-imide in dimethylformamide at 0 degrees C to form ganglioside hydrazides. After removal of excess reagents by column chromatography on silicic acid, the ganglioside 2,4-dinitrophenylhydrazides were eluted from the column and analysed by h.p.l.c. with the use of a silica-gel normal-phase column eluted with an isocratic chloroform/methanol/water/acetic acid system. The addition of CaCl2 improved the separation of GM3 ganglioside containing N-acetylneuraminic acid from that containing N-glycollylneuraminic acid. 2,4-Dinitrophenylhydrazide peaks were measured by the absorbance at 342 nm. Quantification of GM3, GM2, GM1, GD1a, GD1b, GT1b and LM1 gangliosides was linear in a range 0.02-1.6 nmol. GM4, GD3, GT1a and GQ1b gangliosides also yielded distinct peaks, although the range of linearity was not examined. This method was applied to the analysis of the total lipids of rat brain and hepatocytes.

Determination of Reserpine, Hydralazine HCl, and Hydrochlorothiazide in Tablets by Liquid Chromatography on a Short, Normal-Phase Column

1994 ◽  
Vol 77 (5) ◽  
pp. 1104-1108 ◽  
Author(s):  
Ugo R Cieri
Keyword(s):  
Liquid Chromatography ◽  
Mobile Phase ◽  
Normal Phase ◽  
Uv Absorbance ◽  
Commercial Sample ◽  
Second Stage ◽  
Mobile Phases ◽  
Acid Sodium Salt ◽  
Phase Column

Abstract A procedure is presented for the determination of reserpine, hydralazine HCI, and hydrochlorothiazide in tablets by liquid chromatography. The sample is extracted with methanol, and the extract is filtered through paper. Chromatography is performed in 2 stages, each using a 7.5 cm-long normal-phase column but different mobile phases. In the first stage, intended exclusively for reserpine, the mobile phase consists of methanol containing 2% aqueous 1-pentanesulfonic acid sodium salt at 4 parts/1000. Detection and quantitation of reserpine was by fluorescence at 280 nm (excitation) and 360 nm (emission). In the second stage, the amount of the salt solution in the mobile phase was increased to 5%. Detection and quantitation of hydrochlorothiazide and hydralazine HCI was by UV absorbance at 260 nm. One commercial sample of tablets was analyzed by the proposed method. Two determination of each ingredient were made on a ground composite. Ten individual tablets also were examined.

Determination of Reserpine and Hydrochlorothiazide in Commercial Tablets by Liquid Chromatography with Fluorescence and UV Absorption Detectors in Series

1988 ◽  
Vol 71 (3) ◽  
pp. 515-518
Author(s):  
Ugo R Cieri
Keyword(s):  
Liquid Chromatography ◽  
Normal Phase ◽  
Uv Absorption ◽  
Excitation Wavelength ◽  
Alternative Procedure ◽  
Fluorescence Detector ◽  
Two Samples ◽  
In Series ◽  
Phase Column

Abstract A procedure is presented for the determination of reserpine and hydrochlorothiazide in commercial tablets by liquid chromatography (LC). Reference and sample solutions are prepared in methanol. For LC, a normal phase column is used, methanol is the eluting solvent, and 2 detectors are arranged in series. A fluorescence detector set at an excitation wavelength of 280 nm and emission wavelength of 360 nm quantitates reserpine, and a UV absorption detector set at 345 nm determines hydrochlorothiazide. Several synthetic mixtures containing the 2 ingredients in the amounts approximately present in commercial tablets were analyzed by the proposed method. Two samples of commercial tablets were also analyzed; for each sample, 5 determinations were made on a ground composite of 20 tablets; 10 individual tablets were also analyzed. For comparison, some of the solutions were analyzed for each ingredient by an alternative procedure.

Determination of Ajmalicine in Reserpine Raw Materials by Liquid Chromatography with Fluorescence Detection

1995 ◽  
Vol 78 (4) ◽  
pp. 944-945 ◽  
Author(s):  
Ugo R Cieri
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Mobile Phase ◽  
Small Volume ◽  
Raw Materials ◽  
Normal Phase ◽  
Reference Solution ◽  
Acid Sodium Salt ◽  
Phase Column

Abstract A method is presented for determination of ajmalicine in reserpine raw materials by liquid chromatography (LC) with fluorescence detection. The sample is dissolved in a very small volume of chloroform, and the resulting solution is diluted with methanol. The reference solution of ajmalicine is prepared directly in methanol. For LC, a 30 cm long normal-phase column is used. The mobile phase is methanol containing a small volume of an aqueous solution of 1-pentanesulfonic acid, sodium salt. Detection is by fluorescence with excitation at 280 nm and emission at 360 nm. In 3 samples, the ajmalicine contents ranged from 1.2 to 1.9%.

Determination of Reserpine in Commercial Tablets by Liquid Chromatography with Fluorescence Detection

1985 ◽  
Vol 68 (3) ◽  
pp. 542-544
Author(s):  
Ugo R Cieri
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Aqueous Suspension ◽  
Normal Phase ◽  
Chcl3 Extract ◽  
Recovery Study ◽  
Phase Column

Abstract A procedure is presented for the determination of reserpine in commercial tablets by liquid chromatography (LC). The sample is extracted with methanol if only reserpine is present. If the sample contains other ingredients, CHCl3 is used for extraction from aqueous suspension; the CHCl3 is subsequently completely evaporated in the presence of methanol. For LC, a normal phase column, methanol as the eluting solvent, and a fluorometric detector are used. A recovery study indicated that no measurable degradation of reserpine occurs during evaporation of the CHCl3 extract. Several commercial tablets containing reserpine alone or in combination with other ingredients were analyzed by the proposed method, and the results were compared with those obtained by the current official USP methods for reserpine.

scholarly journals Multiresidue Determination of Pesticides in Sediment by Ultrasonically Assisted Extraction and Gas Chromatography/Mass Spectrometry

2005 ◽  
Vol 88 (5) ◽  
pp. 1440-1451 ◽  
Author(s):  
Kuniaki Kawata ◽  
Takashi Asada ◽  
Kikuo Oikawa ◽  
Akiko Tanabe
Keyword(s):  
Column Chromatography ◽  
Internal Standard ◽  
Reversed Phase ◽  
Normal Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Sediment Samples ◽  
Relative Standard ◽  
Phase Column ◽  
Reversed Phase Column

Abstract Agas chromatographic/mass spectrometric (GS/MS) method was developed for the multiple determination of pesticides in sediment. The investigated pesticides included 85 compounds, i.e., 13 fungicides, 43 herbicides, and 29 insecticides. The pesticides were extracted from sediment samples by an ultrasonically assisted procedure. The extract was cleaned up by using reversed-phase column chromatography followed by normal-phase column chromatography. A styrene-divinylbenzene copolymer cartridge and a silica gel cartridge were used as the reversed-phase column and the normal-phase column, respectively. The compounds were determined by GC/MS with 2 internal standard compounds. The overall recoveries were 70–105%, and the relative standard deviations ranged from 1.5 to 18%. The minimum detectable concentrations were 2–10 μg/kg. This method was successfully applied to sediment samples from the Shin River in Niigata, Japan. Twenty-five pesticides (6 fungicides, 11 herbicides, and 8 insecticides) were detected in the sediment samples. The concentrations of the detected pesticides ranged from 3 to 69 μg/kg. Herbicides were found May through July; insecticides and fungicides were found July through August, and during July through September, respectively. The presence of pesticides in the river sediment was correlated with the time of pesticide application in the Shin River basin.

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