scholarly journals FREE GLYCERIN DETERMINATION IN ETHANOL BIODIESEL UTILIZING SPECTROPHOTOMETRIC AND CHROMATOGRAPHIC (GC/FID) METHODS

2017 ◽  
Vol 38 (1) ◽  
pp. 25
Author(s):  
Hilton C. Louzeiro ◽  
Luiz E. B. Soledade ◽  
Antonio G. Souza ◽  
Adeilton P. Maciel ◽  
Fernando C. Silva
Keyword(s):  
Natural Gas ◽  
Present Method ◽  
Chromatographic Method ◽  
Methyl Esters ◽  
Detection Limits ◽  
Ethyl Esters ◽  
National Agency ◽  
Spectrophotometric Methods ◽  
Gas Chromatographic Method

According to the Resolution number 7 from the Brazilian National Agency of Oil, Natural Gas and Biofuels (ANP), the official methodologies for free glycerin determination in biodiesel are the ASTM D 6584, EN 14105 and EN 14106 methods. However, these procedures are limited to the analysis of free glycerin in methyl esters and they are not suitable for the analysis of esters from lauric oils. In the present work, a gas chromatographic method was developed for the determination of the amount of free glycerin in ethyl esters from lauric oils, aiming at overcoming the limitations present in the official methods. Moreover, the present method can also be used for ethanol and methanol biodiesel samples from other oily sources. Besides, a methodology that ascertains the content of free glycerin by UV-Vis spectrophotometry was also applied. Both methods were sensitive enough to determine the content of free glycerin in biodiesel, below the limit specified by the ANP, fixed at 0.02 % (200 mg/L), achieving the detection limits of 5.69 mg/L and 2.17 mg/L for the chromatographic and spectrophotometric methods, respectively.

scholarly journals Gas Chromatographic Determination of Chlorothalonil in Leaves and Roots of Scrophularia and in Soil

1996 ◽  
Vol 79 (2) ◽  
pp. 587-588 ◽  
Author(s):  
Lan Zhao ◽  
De-Fang Fan
Keyword(s):  
Electron Capture ◽  
Chromatographic Method ◽  
Detection Limits ◽  
Chromatographic Determination ◽  
Soil Samples ◽  
Florisil Column ◽  
Glass Column ◽  
Leaves And Roots ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method is described for determination of chlorothalonil residues in leaves and roots of Scrophularia and in soil. Samples were extracted with acetone and cleaned up on a Florisil column. Chlorothalonil residues are chromatographed directly on a glass column of 1.5% OV-17 and 2% QF-1 coated on 80-100 mesh Chromosorb W (HP) support and measured with a 63Ni electron capture detector. Detection limits are 0.001 ppm for leaf, 0.005 ppm for root, and 0.001 ppm for soil.

Add Methanolysis and Gas Chromatographic Determination of Brominated Vegetable Oils in Soft Drinks

1983 ◽  
Vol 66 (6) ◽  
pp. 1385-1389
Author(s):  
James F Lawrence ◽  
Rajinder K Chadha ◽  
Henry B S Conacher
Keyword(s):  
Vegetable Oils ◽  
Chromatographic Method ◽  
Methyl Esters ◽  
Chromatographic Determination ◽  
Soft Drinks ◽  
Packing Material ◽  
Organic Extraction ◽  
Chromatography Columns ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method has been developed for determination of brominated vegetable oils in citrus-flavored soft drinks. Oils were extracted from the drinks with ethyl ether and subjected to acidcatalyzed methanolysis. The resulting brominated methyl esters (dibromostearate, tetrabromostearate, and hexabromostearate) were separated and quantitated as single peaks on a 3% OV-3 column. Chromatography columns were stable for about 3 months of daily use; then the first 15 cm of column packing material was replaced or a new column was prepared. A number of citrus soft drinks were analyzed and contained 3.5-3.9 mg brominated oil/10 fl. oz. Recoveries from spiked samples after organic extraction and methanolysis were 94.5-105%.

Gas Chromatographic Determination of Incurred Dimetridazole Residues in Swine Tissues

1990 ◽  
Vol 73 (5) ◽  
pp. 702-704 ◽  
Author(s):  
David R Newkirk ◽  
Herbert F Righter ◽  
Frank J Schenck ◽  
Joseph L Okrasinski ◽  
Charlie J Barnes
Keyword(s):  
Present Method ◽  
Chromatographic Method ◽  
Chromatographic Determination ◽  
Polarographic Method ◽  
Limited Data ◽  
Withdrawal Time ◽  
Gas Chromatographic Method ◽  
Hydroxy Metabolite

Abstract A gas chromatographic method for determination of 2-hydroxymethyl- 1-methyl-5-nltrolmldazole (DMZOH), the hydroxy metabolite of dimetridazole, in swine muscle has been developed. The method uses cleanup steps similar to those of an earlier polarographic method. The present method Is capable of quantltatlng levels as low as 2 ppb and detecting less than 1 ppb. Recoveries from 30 control tissues spiked at 1,2, or 4 ppb averaged 80.4%. Performance of the method In Incurred tissue was documented and limited data on the depletion of the metabolite In muscle were generated. The muscle of swine given 150 ppm dimetridazole In feed for 14 days contained less than 1 ppb DMZOH at 12 h withdrawal time.

Determination of Small Quantities of Butyric Acid in Fatty Foods Application to Determination of Fatty Material of Butter

1970 ◽  
Vol 53 (5) ◽  
pp. 1082-1084
Author(s):  
A Karleskind ◽  
G Valmalle ◽  
J -P Wolff
Keyword(s):  
Butyric Acid ◽  
Chromatographic Method ◽  
Methyl Esters ◽  
Internal Standard ◽  
Fatty Material ◽  
Acid Decomposition ◽  
Naoh Solution ◽  
Methyl Butyrate ◽  
Gas Chromatographic Method

Abstract A gas chromatographic method is described for the determination of small quantities of butyric acid in fatty foods. After saponification of the fat in the sample and acid decomposition of the soaps formed, the fatty acids are steam distilled and butyric acid and other volatile acids are collected in dilute NaOH solution. The sodium salts formed are dried and then transformed directly into methyl esters. Methyl butyrate is determined by gas chromatography with an internal standard (methyl valerate).

Determination of DDVP in DDVP-Dipterex Formulations by Gas Chromatography

1965 ◽  
Vol 48 (6) ◽  
pp. 1115-1117
Author(s):  
John Ellis ◽  
John Bates
Keyword(s):  
Gas Chromatography ◽  
Electron Capture ◽  
Chromatographic Method ◽  
Spectrophotometric Methods ◽  
Other Substances ◽  
Gas Chromatographic Method

Abstract In the analyses of commercial fly-bait samples for DDVP (0,0-dimethyI-2,2-dichloro vinyl phosphate), containing Dipterex (0,0-dimethyl-2,2,2-trichloro - 1 - hydroxyethyl phosphonate) as a guaranteed ingredient, interferences were observed at 9.9– 10.4/t with the current spectrophotometric methods. These samples were analyzed by an electron capture gas chromatographic method, and the results showed no interference from Dipterex or other substances. A selected group of samples was analyzed by gas chromatography and spectrophotometry, and the results were compared.

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