Gas Chromatographic Determination of Diethylstilbestrol Dimethyl Ether in Diethylstilbestrol

1972 ◽  
Vol 55 (1) ◽  
pp. 185-186
Author(s):  
F E Gainer ◽  
W J Chiasson

Abstract A GLC method is described for the determination of the dimethyl ether of diethylstilbestrol (DME) in diethylstilbestrol (DES). A 1 g sample of DES is dissolved in an aqueous solution of 0.5N NaOH and then extracted with a chloroform solution containing benefin, the internal standard. An aliquot of the chloroform layer is chromatographed and the DME peak is measured relative to the internal standard peak. The method was tested for accuracy within the 11–110 ppm range and a linear plot of detector response vs. concentration was obtained.

1974 ◽  
Vol 57 (1) ◽  
pp. 79-81
Author(s):  
Frank E Gainer ◽  
William J Chiasson

Abstract A gas chromatographic method is described for the determination of the monomethyl ether of diethylstilbestrol (MME) in diethylstilbestrol (DES). A 1 g sample of DES is dissolved in an aqueous solution of 0.5N sodium hydroxide and extracted with a chloroform solution containing benefin, the internal standard. The chloroform solution is back-extracted with sodium hydroxide, and an aliquot is chromatographed after silylation. The MME peaks (cis and trans') are measured relative to the internal standard peak. The method was tested for accuracy within the 120—2000 ppm range, and a linear plot of detector response vs. concentration was obtained. The method is also suitable for the determination of diethylstilbestrol dimethyl ether (DME) if present with MME in a DES sample.


1978 ◽  
Vol 61 (3) ◽  
pp. 500-503
Author(s):  
Leonard R Schronk ◽  
Billy M Colvin ◽  
Alan R Hanks

Abstract Flame ionization gas-liquid chromatography (GLC) with a 10% DC-200 on 80-100 mesh Gas-Chrom Q column is used for the rapid determination of oxydemeton-methyl in commercial formulations. The detector response is linear for 1.0–10.0 μg oxydemeton-methyl, with a sensitivity of 4 ng. The column was stabilized before analysis by injection of a lecithin solution. Samples were diluted with chloroform and injected; peak height ratios were used for quantitation with fluoranthrene as the internal standard. Carbaryl was removed from mixed formulations by silica gel chromatography, oxydemeton- methyl was eluted with methanolchloroform (2+98), and the eluate was collected for infrared (IR) and GLC analyses. Methoxychlor and Karathane were removed by chromatography on Florisil before IR analysis. GLC results compare favorably with those for IR, with recoveries ranging from 98.44 to 102.88% for spiked formulations.


1981 ◽  
Vol 64 (4) ◽  
pp. 833-840
Author(s):  
Erika E Hargesheimer ◽  
Ronald T Coutts ◽  
Franco M Pasutto

Abstract A simple gas-liquid chromatographic (GLC) method has been developed which provides sensitivity and specificity for the analysis of complex mixtures of the commonly occurring herbicide metabolites aniline, 3-chloroaniline, 4-chloroaniline, 4-bromoaniline, and 3-chloro-4-methylaniline. All of these anilines react with acetic anhydride directly in basified aqueous solution. Further reaction of the acetylated anilines with trifluoroacetic anhydride gave diacyl derivatives which were readily resolved by gas chromatography. The structures of the N-acetylated and IV-trifluoroacetylated derivatives of benzylamine (internal standard) and the anilines were confirmed by GLC-mass spectrometry. In distilled water the minimum detectable concentrations of aniline and the substituted anilines, using electron capture GLC, are 0.1 nmole/100 mL and 0.05 nmole/100 mL, respectively. The detection limit for the anilines is 1 nmole/100 ml distilled water, using GLC with flame ionization detection. The technique was applied to the determination of anilines added to urine samples obtained from the general population.


1984 ◽  
Vol 30 (2) ◽  
pp. 319-322 ◽  
Author(s):  
W Mastropaolo ◽  
D R Holmes ◽  
M J Osborn ◽  
J Rooke ◽  
T P Moyer

Abstract In this improved reversed-phase liquid-chromatographic procedure for determination of mexiletine in plasma, mexiletine and an internal standard, chlorodisopyramide, are extracted with methylene chloride from 0.5 mL of serum or plasma; the extract is then concentrated and injected onto a C18 chromatographic column. Mexiletine in the column effluent is detected by monitoring absorbance at 210 nm. It is quantified by use of mexiletine-internal standard peak-height ratios. The relation between this ratio and mexiletine concentration is linear from 0.1 to 5.0 mg/L. The lower limit of detection is about 50 micrograms/L. At a mexiletine concentration of 2.0 mg/L in serum, intrarun precision (CV) is 2.9% and inter-run precision is 5.9%; at 0.5 mg/L, these CVs are 5.7% and 9.6%, respectively. Analytical recovery of added mexiletine in serum is 68-88%. Therapeutic concentrations of some commonly administered drugs in patients' specimens did not interfere. In serum from 38 patients receiving mexiletine for cardiac arrhythmia, concentrations measured by this method correlated with therapeutic efficacy.


1981 ◽  
Vol 64 (6) ◽  
pp. 1315-1318
Author(s):  
Peter D Bland ◽  
◽  
J Bagness ◽  
W Black ◽  
L Brown ◽  
...  

Abstract A method is described for the determination of pirimicarb (2-(dimethylamino)-5,6-dimethyl-4-pyrimidinyl dimethylcarbamate) in formulated products by gas-liquid chromatography (GLC). Samples are dissolved in a chloroform solution of an internal standard and injected into a gas chromatograph equipped with a flame ionization detector. Quantitative data are obtained by comparing peak areas of the compound and internal standard with those obtained by injecting a standard solution. Eleven collaborators made replicate determinations on 6 samples including a technical product, a granular product, and 4 powder products. The average coefficient of variation was 1.14% for the technical product, 1.82% for the granular product, and 0.73% for the powder products.


1983 ◽  
Vol 48 (3) ◽  
pp. 722-734
Author(s):  
Martin Koval

The flame ionisation detector response to C6-C11 aliphatic hydrocarbon solutions in carbon disulphide in the concentration range between 1.3-9.5 mg ml-1 retained lineary despite the excess of solvent entering the detector simultaneously with the analyte. Pure carbon disulphide exhibited a small positive detector response which did not interfere in calibration procedure and which, under certain GC conditions, inverted to negative values. This response was not proportional to the injected volume and was strongly influenced by the column temperature and/or bleed. On the basis of these findings, a method compatible with the widely used charcoal tube carbon disulphide desorption procedure was developed and evaluated. It consists of static desorption of the sum of aliphatic alkanes and cycloalkanes from the activated charcoal after which an internal standard is added to the supernatant eluate. The resulting carbon disulphide solution is analysed on a highly polar stationary phase 1,2,3-tris(2-cyanoethoxy)propane where the solvent and the analyte coelute in a single peak, the height of which is practically proportional to the sum of alkanes and cycloalkanes present. This also makes determinations of other substances present in the sample more simple. The field test of the proposed method yielded values comparable in precision and accuracy with a control infrared spectrophotometric method.


2013 ◽  
Vol 96 (6) ◽  
pp. 1302-1307 ◽  
Author(s):  
Karim Michail ◽  
Hoda Daabees ◽  
Youssef Beltagy ◽  
Magdy Abd Elkhalek ◽  
Mona Khamis

Abstract A validated HPLC-UV method is presented for the quantification of urinary memantine hydrochloride, a novel medication approved to treat moderate and advanced cases of Alzheimer's disease. The drug and amantadine hydrochloride, the internal standard, were extracted from human urine using SPE. The extract was then buffered and derivatized at room temperature using o-phthalaldehyde in the presence of N-acetyl-L-cyteine. Chromatographic separation of the formed derivatives was achieved on a C18 column using methanol–water mobile phase adjusted to pH 7 and pumped isocratically at 1 mL/min. The UV detector was set at 340 nm. The chromatographic run time did not exceed 10 min. The LOD and LOQ were 8 and 20 ng/mL, respectively. The RSDs for intraday and interday precisions did not exceed 5.5%. The method was used to monitor memantine hydrochloride in human urine in order to determine an appropriate sampling interval for future noninvasive therapeutic drug monitoring. The assay could also be applied to the determination of amantadine. The described assay showed that a postdosing time interval of 25–75 h seems adequate for sampling and monitoring memantine in urine.


1984 ◽  
Vol 30 (5) ◽  
pp. 784-787 ◽  
Author(s):  
R A Gibson ◽  
L Lattanzio ◽  
H McGee

Abstract Metronidazole and its known metabolites in plasma can be rapidly separated by a "high-pressure" liquid-chromatographic method that can also be adapted for rapid determination of tinidazole. Samples deproteinized with trichloroacetic acid (50 g/L final concentration) undergo isocratic separation on a reversed-phase C18 column eluted with an 8/92 (by vol) mixture of acetonitrile/KH2PO4 (5 mmol/L, pH 3.0). The method is sensitive, reliably detecting as little as 25 micrograms of metronidazole and (or) its metabolites per milliliter of plasma. The detector response varied linearly with concentration for all compounds tested over a wide range (25-500 micrograms/L). Within-day and between-day variation was generally less than 2.5% for all concentrations of all compounds tested. Various other antibiotics tested did not interfere.


2003 ◽  
Vol 68 (11) ◽  
pp. 883-892 ◽  
Author(s):  
Dragica Zendelovska ◽  
Trajce Stafilov

A rapid, specific and sensitive high-performance liquid chromatographic method for the determination of famotidine in human plasma has been developed. Famotidine and the internal standard were chromatographically separated from plasma components using a Lichrocart Lichrospher 60 RP select B cartridge for solid-phase separation with a mobile phase composed of 0.1 % (v/v) triethylamine in water (pH 3) and acetonitrile (92:8, v/v). UV detection was set at 270 nm. The calibration curve was linear in the concentration range of 10.0 ? 350.0 ng mL-1. The method was implemented to monitor the famotidine levels in patient samples.


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