Gas-chromatographic determination of cholesterol sulfate in plasma and erythrocytes, for the diagnosis of recessive X-linked ichthyosis.

1983 ◽  
Vol 29 (7) ◽  
pp. 1404-1407 ◽  
Author(s):  
F A Muskiet ◽  
G Jansen ◽  
B G Wolthers ◽  
A Marinkovic-Ilsen ◽  
P C van Voorst Vader
Keyword(s):  
Internal Standard ◽  
Dehydroepiandrosterone Sulfate ◽  
Chromatographic Determination ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Single Step ◽  
Flame Ionization Detection ◽  
Cholesterol Sulfate ◽  
Flame Ionization

Abstract We describe a rapid method for determining cholesterol sulfate in plasma and erythrocytes. After its single-step isolation by means of anion-exchange chromatography cholesterol sulfate is hydrolyzed, trimethylsilylated, and determined by gas chromatography with flame ionization detection. 5 beta-Cholestan-3 alpha-ol sulfate is used as internal standard. The method enables simultaneous determination of dehydroepiandrosterone sulfate in plasma. We applied it for the diagnosis of seven patients with recessive X-linked ichthyosis. Concentrations are given for plasma and erythrocytes from four unaffected relatives of patients with X-linked ichthyosis, a patient with placental sulfatase deficiency, two patients with other types of ichthyoses, and 20 controls. The method may also be of use for the rapid isolation of other organic sulfates from biological material, as illustrated by a comparison of gas chromatograms of urine from a normal pregnant woman and that from a patient with placental sulfatase deficiency.

Gas Chromatographic Determination of Nonvolatile Organic Acids in Sap of Sugar Maple (Acer saccharum Marsh.)

1984 ◽  
Vol 67 (6) ◽  
pp. 1125-1129
Author(s):  
Joseph N Mollica ◽  
Maria Franca Morselli
Keyword(s):  
Organic Acids ◽  
Sap Flow ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Maple Sap

Abstract Qualitative analysis of organic acids has never been reported for sugar maple sap, but only for its products, "sugar sand" and maple syrup. A gas chromatographic (GC) method is described for the simultaneous determination of up to 13 nonvolatile organic acids in sugar maple sap. Sap is filtered through Celite, and acids are isolated via cation- and anion-exchange chromatography. Reaction of dried acids with BSA [N,O-bis(trimethylsilyl)acetamide] in the presence of pyridine and methoxyamine hydrochloride yields the more volatile TMS (trimethylsilyl) esters. Oxalic, succinic, fumaric, L-malic, tartaric, cis-aconitic, citric, and/or shikimic acids were found in maple sap at concentrations ranging from less than 50 ppb to more than 45 ppm, depending on the particular acid and the date of sap flow. Percent recoveries and coefficients of variation for the acids at the 500 ppm level were 46.0 (3.2), 92.0 (2.9), 73.0 (0.77), 94.0 (2.0), 95.0 (−), 72.0 (−), and 97.0 (0.38), respectively. Various amounts of nonvolatile organic acids are reported in the sap of one sugar maple tree throughout a sap season, and of 3 individual maples during an early sap flow. Quantitation limits were as low as 15 ppb for individual acids in the analysis of a 100 mL sap sample. Esters were separated on a mixed liquid phase column of 4% SE-52/2% SE-30 on Chromosorb W-HP. They were identified by relative retention time, using a dual flame ionization detector. Naphthalene was used as the internal standard. Concurrent identification of pyruvic, malonic, glutaric, α-ketoglutaric, cis-aconitic, and isocitric acids with those previously mentioned is also possible.

Improved Cleanup and Derivatization for Gas Chromatographic Determination of Monosodium Glutamate in Foods

1983 ◽  
Vol 66 (6) ◽  
pp. 1528-1531 ◽  
Author(s):  
Hiroshi Nakanishi
Keyword(s):  
Glutamic Acid ◽  
Acid Derivative ◽  
Monosodium Glutamate ◽  
Chromatographic Determination ◽  
Flame Ionization Detection ◽  
Gas Chromatograph ◽  
Flame Ionization ◽  
Acetone Water ◽  
Chromatographic Procedure

Abstract A gas chromatographic procedure is described for determining monosodium glutamate (MSG) in several types of food. A sample is extracted with acetone- water (1 + 1). Acetone is evaporated and an aliquot of the extract is buffered with 1M NH4OH-1M NH4CI pH 9 solution, and chromatographed directly on a column of QAE Sephadex A-25 that has been pretreated with the same buffer. MSG is eluted with 0.1N HC1, and a portion of the eluate is evaporated to dryness and reacted with dimethylformamide( DMF)-dimethylacetal to form the glutamic acid derivative, which is injected into a gas chromatograph and measured by flame ionization detection. Recoveries of MSG from sample fortified at 5-500 mg ranged from 92.8 to 100%.

Capillary Gas Chromatographic Determination Of Cypermethrin In Formulations: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 592-595
Author(s):  
Peter D Bland
Keyword(s):  
Active Ingredient ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Fused Silica ◽  
Flame Ionization ◽  
Wettable Powder ◽  
Peak Areas ◽  
Liquid Concentrate

Abstract A method is described for the determination of cypermethrin, 3-(2,2- dichloroethenyl)-2,2-dimethyl-cyclopropanecarboxylate cyano-(3- phenoxyphenyl)methyl ester, in technical and formulated material by capillary gas chromatography (CGC). Samples of technical or formulated material are dissolved in CH2Cl2 containing dicyclohexyl phthalate as internal standard. The solution is injected into a gas chromatograph fitted with a flame ionization detector and capillary column of 25 m x 0.32 mm fused silica with a thick film OV-1 phase at 240°C. Injection is made into a heated injection port fitted with an antidiscrimination device in a split mode. Peak areas obtained at retention times of the internal standard and active ingredient are measured with an integrator. The quantity of cypermethrin is determined by comparing the internal standard and active ingredient peak areas with those obtained from a calibration solution containing known amounts of internal standard and pure active ingredient. Five samples were chosen for collaborative study: technical cypermethrin, 70% liquid concentrate, 3 lb/US gal. emulsifiable, 3 ib/US gal. oil concentrate, and 40% wettable powder. Twelve collaborators carried out replicate determinations on each sample on separate days. Coefficients of variation between laboratories (CVX) were 2.13 for the technical, 2.94 for the emulsifiable concentrate, 3.51 for the liquid concentrate, 2.66 for the wettable powder, and 2.29 for the oil concentrate. The method was adopted official first action.

Gas-Liquid Chromatographic Determination of Tetradif on Technical and Formulations: Collaborative Study

1981 ◽  
Vol 64 (4) ◽  
pp. 829-832
Author(s):  
Bram Van Rossum ◽  
Albertus Martijn ◽  
James E Launer ◽  
◽  
E C Calamita ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Flame Ionization ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The gas-liquid chromatographic determination of tetradifon technical and formulations was collaboratively studied in duplicate with 12 laboratories. Six samples were dissolved in dichloroethane with n-hexacosane as the internal standard, chromatographed on a column of 3% SE-52, and detected by flame ionization. The average coefficients of variation were 1.2% for the 2 technical samples, 1.6% for the 2 wettable powders, and 1.5% for the 2 emulsifiable concentrates. The method has been adopted official first action.

Gas-Liquid Chromatographic Determination of Pyridazinones in Technical Products and Formulations

1978 ◽  
Vol 61 (1) ◽  
pp. 161-163
Author(s):  
Giuseppe Cellerino ◽  
Mariarosa Re
Keyword(s):  
Internal Standard ◽  
Standard Technique ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Selective Detector ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Technical Products

Abstract Simultaneous determination of the active ingredient and of by-products in technical and formulated pyridazinones was rapidly performed by gas-liquid chromatography with complete resolution of all compounds. Quantitative determination by the internal standard technique is accurate and precise. The lower limit of detectability is 8 × 10–12 g/sec with a flame ionization detector and 1 × 10–12 g/sec with a nitrogen-phosphorus selective detector operating in the nitrogen mode.

Gas-Liquid Chromatographic Determination of Oxydemeton-Methyl in Commercial Formulations

1978 ◽  
Vol 61 (3) ◽  
pp. 500-503
Author(s):  
Leonard R Schronk ◽  
Billy M Colvin ◽  
Alan R Hanks
Keyword(s):  
Rapid Determination ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Detector Response ◽  
Gel Chromatography ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Silica Gel Chromatography

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.

Gas Chromatographic Measurement of Benzoyl Peroxide (as Benzoic Acid) in Cheese

1974 ◽  
Vol 57 (3) ◽  
pp. 706-709
Author(s):  
Albert B Karasz ◽  
Frank DeCocco ◽  
John J Maxstadt
Keyword(s):  
Gas Chromatography ◽  
Benzoic Acid ◽  
Benzoyl Peroxide ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Ether Extract ◽  
Average Recovery ◽  
Flame Ionization ◽  
Chromatographic Measurement

Abstract Benzoyl peroxide bleach, added to cheese, is estimated by gas chromatographic determination of benzoic acid, its principal reduction product. Copper is added to the acidified ether extract of the cheese to reduce the residual bleach, and solvent partitioning and permanganate treatment are used for purification. The benzoic acid is transferred to chloroform containing lauric acid as an internal standard and determined by flame ionization gas chromatography, with a column containing 5% FFAP + 0.5% H3PO4 on Chromosorb W. The average recovery of added benzoyl peroxide was 82.0% and the standard deviation was 0.0128. The occurrence of benzoic acid of microbial origin in cheese poses a problem in accurately determining added benzoyl peroxide from the benzoic acid found in a sample.

Gas-Liquid Chromatographic Determination of p-Chloroacetanilide in Acetaminophen

1978 ◽  
Vol 61 (1) ◽  
pp. 68-71
Author(s):  
Dorothy K Wyatt ◽  
Lee T Grady
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Flame Ionization ◽  
Glass Column ◽  
Retention Characteristics ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Gas-liquid chromatography (GLC) coupled with column chromatography was used to accurately determine as little as 25 ppm p-chloroacetanilide in acetaminophen. p-Chloroacetanilide was eluted from a pH 8 phosphate-buffered diatomite partition column by using purified tetrachloroethylene (acetaminophen was retained). This solution was concentrated, internal standard (docosane) was added, and p-chloroacetanilide was determined by using a 0.9 m × 2 mm glass column packed with 3% Poly A 103 on Supelcoport and a flame ionization detector with electronic integration. Standard curves were linear for 10–100 ppm p-chloroacetanilide. Various chromatographic materials were investigated for optimal retention characteristics. High pressure liquid chromatography (HPLC) was also evaluated as an alternative; however, lack of reproducibility of the HPLC column favored the GLC procedure.

Direct Blood-Injection Method for Gas Chromatographic Determination of Alcohols and Other Volatile Compounds

1971 ◽  
Vol 17 (2) ◽  
pp. 82-85 ◽  
Author(s):  
Naresh C Jain
Keyword(s):  
Sample Preparation ◽  
Volatile Compounds ◽  
Low Cost ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Gas Chromatograph ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Blood Injection

Abstract An extremely simple, rapid method is described for simultaneously determining methanol, ethanol, acetone, isopropanol, and low-boiling hydrocarbons associated with glue sniffing. Less than 1 µl of blood, mixed with an internal standard, is injected directly into a low-cost gas chromatograph equipped with a flame-ionization detector. No extraction, distillation, and (or) sample preparation is required, and the method is sensitive to less than 10 µg of alcohol per ml.

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