Analysis of Thiamine in Pinto Beans by Gas Chromatography of the Sulfite Cleavage Product 5-(2-Hydroxyethyl)-4-methylthiazole

1973 ◽  
Vol 56 (5) ◽  
pp. 1273-1276
Author(s):  
Richard M Seifert ◽  
Charlotte Fung Miller
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Retention Time ◽  
Chromatographic Method ◽  
Cleavage Product ◽  
Pinto Bean ◽  
Pinto Beans ◽  
Gas Chromatographic Method ◽  
Good Agreement

Abstract A gas chromatographic method has been developed for the analysis of thiamine in pinto beans. The method should be applicable to other products. Thiamine is extracted and then quantitatively split by sulfite treatment to give the ether-extractable 5-(2-hydroxyethyl)-4-methylthiazole. The thiazole was analyzed by GLC. Its purity and identity were confirmed by mass spectrometry and GLC retention time. Total thiamine (as the HCl) calculated from the analyzed thiazole averaged 164 ±16 μg/25 g pinto beans. Recovery of total thiamine in 25 g pinto bean samples containing added thiamine HCl (100–500 μg) ranged from 97 to 83%. GLC analysis of pinto bean samples was in good agreement with analysis by the thiochrome method at levels of 5.9–8.6 μg/g, but results were more variable at lower levels.

The Confirmation of Diethylstilbestrol Residues in Beef Liver by Gas Chromatography-Mass Spectrometry

1975 ◽  
Vol 58 (3) ◽  
pp. 520-524
Author(s):  
Edgar W Day ◽  
Lynn E Vanatta ◽  
Robert F Sieck
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Chromatographic Method ◽  
Gas Chromatography Mass Spectrometry ◽  
Confirmatory Test ◽  
Beef Liver ◽  
Isotope Pattern ◽  
Chromatography Mass Spectrometry ◽  
Growth Promoting ◽  
Gas Chromatographic Method

Abstract A confirmatory test for the presence of the growth-promoting hormone, diethylstilbestrol (DES), in beef liver is described. Samples are subjected to a published electron capture gas chromatographic method that involves the formation and measurement of the bis-dichloroacetyl derivative of DES. The presence of the derivative is then confirmed by gas chromatography-mass spectrometry, using a repetitive scanning technique to maximize response. The isotope pattern of the tetrachlorinated molecular ion greatly facilitates the confirmation.

Analysis of Total Free and Glucose-Conjugated Pyrethroid Acid Metabolites in Tea Infusions as Hexafluoroisopropyl Esters by Gas Chromatography with Electron Capture Detection

1995 ◽  
Vol 78 (3) ◽  
pp. 846-855 ◽  
Author(s):  
Richard D Mortimer ◽  
Dorcas F Weber ◽  
Wing F Sun
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Electron Capture ◽  
Chromatographic Method ◽  
Electron Capture Detection ◽  
Tea Leaves ◽  
Tea Infusions ◽  
Acid Metabolites ◽  
Pyrethroid Metabolites ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method with electron capture detection (GC–ECD) has been developed to quantitate the sum of free acids of pyrethroid metabolites, their glucosides, and their other base-cleav-able conjugates that are extracted from tea leaves when a tea infusion is prepared. Four representative glucoside conjugates were synthesized; hydrolytic conditions were established; and extraction, derivatization and GC conditions were developed for analysis of these pyrethroid acid metabolites at ≥0.01 ppm on dry tea. GC/mass spectrometry was used to confirm assignment of residues found in some tea samples.

Measurement of diphenylhydantoin in 0.1-ml plasma samples: gas chromatography and radioimmunoassay compared.

1976 ◽  
Vol 22 (2) ◽  
pp. 246-249 ◽  
Author(s):  
M L'Estrange Orme ◽  
O Borgå ◽  
C E Cook ◽  
F Sjöqvist
Keyword(s):  
Gas Chromatography ◽  
Chromatographic Method ◽  
Plasma Samples ◽  
Excellent Correlation ◽  
Chromatographic Procedure ◽  
Uremic Patients ◽  
Gas Chromatographic Method ◽  
The Cost ◽  
Good Agreement

Abstract Concentrations of diphenylhydantoin in 364 plasma samples have been measured both by radioimmunoassay and with a recently developed gas-chromatographic method, which requires only 0.1 ml of plasma per determination. There was an excellent correlation between values obtained by the two methods (r = 0.986), and in only 11 plasma samples did the results differ by more than 20%. Of the investigated samples, 105 were obtained from uremic patients. For these, an equally good agreement was obtained between the two methods. Within-assay variance was 3.1% for the immunoassay and 3.3% for the gas-chromatographic procedure. Without automatic pipetting equipment, the radioimmunoassay procedure took twice as long as the chromatographic assay, and the cost of chemicals was considerably higher. Nevertheless, the better sensitivity of the radioimmunoassay makes it of great value, especially in children, because plasma samples of 10 to 20 mul can be used.

The Importance of Alcohol Testing by Gas Chromatography vs the Cordebard Classical Method Modified in the Medico Legal Investigation

2018 ◽  
Vol 69 (9) ◽  
pp. 2407-2410
Author(s):  
Dan Perju Dumbrava ◽  
Carmen Corina Radu ◽  
Sofia David ◽  
Tatiana Iov ◽  
Catalin Jan Iov ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Chromatographic Method ◽  
Classical Method ◽  
Blood Alcohol Concentration ◽  
Alcohol Concentration ◽  
Blood Alcohol ◽  
Technical Details ◽  
Gas Chromatographic Method ◽  
Alcohol Testing ◽  
Living Person

Considering the growing number of requests from the criminal investigations authorities addressed to the institutions of legal medicine, testing of blood alcohol concentration both in the living person and in the corpse, we believe that a presentation of the two methods which are used in our country, is a topic of interest at present. The purpose of this article is to provide the reader with the technical details on how blodd alcohol concentration is realised by means of the gas chromatographic method and the classical one, (Cordebard modified by D. Banciu and I. Droc) respectively. Another purpose of this article is to also show, in a comparative way, the elements that make the gas chromatographic method superior to the former one.

Gas Chromatographic Determination of N-Butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine and α,α,α-Trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine in Formulations

1971 ◽  
Vol 54 (3) ◽  
pp. 711-712
Author(s):  
Martha Fuzesi
Keyword(s):  
Gas Chromatography ◽  
Quantitative Determination ◽  
Electron Capture ◽  
Chromatographic Method ◽  
Chromatographic Determination ◽  
Electron Capture Detector ◽  
Reference Solution ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method is described for the quantitative determination of N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-tolindine and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyI-p-toluidine herbicides in formulations. The sample is extracted with benzene, and equal amounts of sample and reference solution in the same concentration range are analyzed by gas chromatography, using an electron capture detector and an SE-30/Diatoport S column. The method has been applied successfully to laboratory-prepared and commercial samples.

Antioxidants (BHA and BHT) in Breakfast Cereals

1965 ◽  
Vol 48 (4) ◽  
pp. 694-699
Author(s):  
David M Takahashi
Keyword(s):  
Gas Chromatography ◽  
Petroleum Ether ◽  
Chromatographic Method ◽  
Steam Distillation ◽  
Gas Chromatograph ◽  
Breakfast Cereals ◽  
Collaborative Studies ◽  
Different Types ◽  
Gas Chromatographic Method

Abstract Antioxidants (BHA and BHT) in different types of breakfast cereals were studied by argon ionization gas chromatography. Samples containing antioxidants were packed into the column, and antioxidants were eluted with redistilled petroleum ether. EIuates were concentrated under N2 and injected into a Barber-Colman Model 10 gas chromatograph. Recoveries ranged from about 92 to 110%. Results obtained by steam distillation-colorimetry methods were erratic. Colorimetric procedures were not free from interferences and could lead to highly erroneous results at the lower ppm levels. The gas chromatographic method is faster, simpler, and more accurate. Collaborative studies on corn and rice ready-to-eat breakfast cereals are recommended.

scholarly journals The Use of Cryogenic Temperature Gas Chromatography for the Determination of Carbon Monoxide and Carbon Dioxide in Cigarette Smoke

1972 ◽  
Vol 6 (4) ◽  
Author(s):  
G.P. Morie ◽  
C.H. Sloan
Keyword(s):  
Carbon Dioxide ◽  
Gas Chromatography ◽  
Carbon Monoxide ◽  
Liquid Nitrogen ◽  
Cigarette Smoke ◽  
Cryogenic Temperature ◽  
Chromatographic Method ◽  
Porapak Q ◽  
Gas Chromatographic Method

AbstractA gas chromatographic method for the determination of carbon monoxide and carbon dioxide in cigarette smoke was developed. A column containing Porapak Q packing and a cryogenic temperature programmer which employed liquid nitrogen to cool the column to subambient temperatures was used. The separation of N

Comparison of Emmerie-Engel Method and Gas Chromatographic Method for Determination of Supplemental α-Tocopheryl Acetate in Feed Concentrates

1987 ◽  
Vol 70 (3) ◽  
pp. 417-419
Author(s):  
Michael P Labadie ◽  
Charles E Boufford
Keyword(s):  
Gas Chromatography ◽  
Vitamin E ◽  
Coefficient Of Variation ◽  
Chromatographic Method ◽  
Tocopheryl Acetate ◽  
High Potency ◽  
Gc Analysis ◽  
Gas Chromatographic Method ◽  
Official Procedure

Abstract The determination of supplemental a-tocopheryl acetate in high potency vitamin E powders and oils was compared using the Emmerie- Engel method and gas chromatography (GC). The Emmerie-Engel reaction requires saponification, extraction of the saponiflable fracaon, and quantitation by colorimetry. GC analysis requires only an extraction and/or dilution before quantitation. These are represented essentially by AOAC methods 43.147-43.151 (colorimetry) and 43.152-43.159 (GC) for high potency vitamin E concentrates. Each method was statistically evaluated for precision and sample-to-sample reproducibility. Each Emmerie-Engel value was divided by the GC value obtained for the same sample; an average of 1.049 with a coefficient of variation of 2.89% was obtained. It was concluded that (he GC procedure was superior to the Emmerie-Engel method, and ahould be the official procedure for determination of supplemental a-tocopheryl acetate in feed concentrates.

Capillary Column Gas Chromatographic Determination of Trace Residues of the Herbicide Chlorsulfuron in Agricultural Runoff Water

1987 ◽  
Vol 70 (4) ◽  
pp. 745-748
Author(s):  
Uaz Ahmad
Keyword(s):  
Gas Chromatography ◽  
Chromatographic Method ◽  
Capillary Column ◽  
Methylene Chloride ◽  
Chromatographic Determination ◽  
Agricultural Runoff ◽  
Runoff Water ◽  
Florisil Column ◽  
Gas Chromatographic Method

Abstract A capillary column gas chromatographic method is described for determining parts-per-trillion (ppt) levels of chlorsulfuron in agricultural runoff water. The water sample is acidified with acetic acid and extracted with methylene chloride. The chlorsulfuron in the extract is derivatized to its monomethyl derivative. After Florisil column cleanup, the methylated chlorsulfuron is determined by electron-capture gas chromatography. Recovery of chlorsulfuron from fortified water samples is greater than 80%. Detection limit of the method is 25 ng chlorsulfuron/L water (25 ppt). There are 2 reaction sites on the chlorsulfuron molecule, both of which are susceptible to methylation leading to monomethyl chlorsulfuron and dimethyl chlorsulfuron. A procedure is described to methylate selectively the sulfonamide nitrogen of chlorsulfuron.

Determination of Phytosterols in Butter Samples by Using Capillary Column Gas Chromatography

1987 ◽  
Vol 70 (5) ◽  
pp. 912-915 ◽  
Author(s):  
Randall L Smith ◽  
Darryl M Sullivan ◽  
Earl F Richter
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Retention Time ◽  
Capillary Column ◽  
Limit Of Detection ◽  
Packed Column ◽  
Gas Chromatography Mass Spectrometry ◽  
Positive Bias ◽  
Capillary Column Gas Chromatography

Abstract A positive bias in the gas chromatographic (GC) analysis of butter for β-sitosterol was discovered when attempting to confirm values by gas chromatography/mass spectrometry (GC/MS). The source of the problem was traced to an interfering material that was not effectively separated by packed column GC. Because capillary columns are known to provide superior separation, they were substituted for packed columns in the assay, and instrument parameters were modified accordingly. A compound with a similar retention time, identified by GC/MS as lanosterol, was separated from β-sitosterol by the capillary column. The capillary column technique was applied to over 300 butter samples. The results indicate that the method can accurately quantitate β-sitosterol in butter with no known interferences. The limit of detection for this method is 1 mg/100 g. Recoveries at a level of 3 mg/100 g averaged 98% with a coefficient of variation of 3.45%

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