Simple Colorimetric Determination of Carrageenan in Jellies and Salad Dressings

1991 ◽  
Vol 74 (6) ◽  
pp. 1019-1022 ◽  
Author(s):  
Yoshie Yabe ◽  
Takahiro Ninomiya ◽  
Takashi Tatsuno ◽  
Taro Okada
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Alcian Blue ◽  
Coefficient Of Variation ◽  
Capillary Gas Chromatography ◽  
Colorimetric Method ◽  
Sample Solution ◽  
Colorimetric Determination ◽  
Chromatography Method

Abstract A simple, rapid colorimetric method is described for the determination of carrageenan (CAR) in foods such as jellies and salad dressings. Alcian blue reagent is added to the sample solution prepared from these foods, then CAR is precipitated selectively as a CAR-alcian blue complex. The precipitate is dissolved in monoethanolamine and determined colorimetrically at 615 nm. Overall recovery for jelly was 93.3% with a coefficient of variation (CV) of 5.8%. Overall recovery for salad dressing was 91.9% with a CV of 3.0%. The detection limit was 0.05%. The results obtained by the proposed method were similar to those obtained by a capillary gas chromatography method.

scholarly journals Simultaneous Determination of Florfenicol and Florfenicol Amine in Fish, Shrimp, and Swine Muscle by Gas Chromatography with a Microcell Electron Capture Detector

2006 ◽  
Vol 89 (5) ◽  
pp. 1437-1442 ◽  
Author(s):  
Suxia Zhang ◽  
Fengyun Sun ◽  
Jiancheng Li ◽  
Linli Cheng ◽  
Jianzhong Shen
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Simultaneous Determination ◽  
Electron Capture ◽  
Solid Phase ◽  
Electron Capture Detector ◽  
Phase Extraction ◽  
Chromatography Method ◽  
Residue Study

Abstract A rapid and sensitive gas chromatography method was developed for the simultaneous determination of florfenicol (FF) and its metabolite florfenicol amine (FFA) in fish, shrimp, and swine muscle. The extracted samples were defatted with hexane and cleaned up by solid-phase extraction using Oasis MCX cartridges. The eluate was evaporated to dryness, and residues were derivatized and determined by gas chromatography with a microcell electron capture detector. Overall average recoveries ranged from 81.7 to 109.7% for fish, 94.1 to 103.4% for shrimp, and 71.5 to 91.4% for swine muscle. The detection limit was 0.5 ng/g for FF and 1 ng/g for FFA, respectively. The method was validated for the determination of incurred swine muscle samples in an actual residue study.

Colorimetric Determination of Total Iodine in Foods by Iodide-Catalyzed Reduction of Ce+4

1986 ◽  
Vol 69 (4) ◽  
pp. 687-689 ◽  
Author(s):  
Peter W F Fischer ◽  
Mary R L’Abbé ◽  
Alexandre Giroux
Keyword(s):  
Detection Limit ◽  
Reference Material ◽  
Standard Reference Material ◽  
Dairy Products ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
Acid Digestion ◽  
Total Iodine ◽  
Relative Standard

Abstract An earlier acid digestion determination of iodine in foods was modified to provide an improved detection limit and to allow for the analysis of a greater variety and larger amounts of foods. The organic material in the sample was oxidized overnight by concentrated nitric acid, followed by digestion in a mixture of concentrated sulfuric and 70% perchloric acid. The iodine was determined by an automated colorimetric method based on the iodide-catalyzed reduction of Ce+4 by As+3. The method had an average relative standard deviation of 3.1% for the samples analyzed, and a detection limit of 0.1 ng/mL in the digested solution and 5 ng/g in a 2 g sample prior to digestion. The recovery of added iodine ranged from 90.3 to 101.3%, using external standards. Samples analyzed included NBS Standard Reference Material 1549, and composites of a variety of dairy products, meat, eggs and fish, cereals, and potatoes. The iodine detected in these samples ranged from 9 ng/g for the potato group to 3360 ng/g for the standard reference material.

Determination of Honey Authenticity by Capillary Gas Chromatography

1995 ◽  
Vol 78 (5) ◽  
pp. 1210-1218 ◽  
Author(s):  
Nicholas H Low ◽  
Wendy South
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
North America ◽  
Capillary Gas Chromatography ◽  
Invert Sugar ◽  
Trimethylsilyl Ethers ◽  
Low Concentrations ◽  
Sugar Addition

Abstract Methodology using capillary gas chromatography was developed to determine addition of invert syrups (beet or cane) to honey. Fingerprint oligosaccharides, which were either not detectable or present in low concentrations in pure honey, were found in these inexpensive sweeteners. Oligosaccharides were analyzed as their trimethylsilyl ethers. Sixty-eight pure honey samples produced in continental North America, Hawaii, China, and Australia were analyzed. The detection limit for invert sugar addition was 5%.

Colorimetric Determination of Selenium in Premixes and Supplements

1992 ◽  
Vol 75 (2) ◽  
pp. 269-271 ◽  
Author(s):  
Jeffrey A Hurlbut ◽  
Roger G Burkepile ◽  
Carolyn A Geisler
Keyword(s):  
Sulfuric Acid ◽  
Formic Acid ◽  
Coefficient Of Variation ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
High Concentrations

Abstract A colorimetric method Is described for the determination of 100-10 000 μg selenlum/g premix. Selenium Is present in premixes as either selenite or selenate. Moderate to high concentrations of several common minerals are tolerated. The premix is briefly digested In a sulfuric acid-perchloric acidsodium molybdate mixture, boiled in 10% NaCI solution, made basic, and centrifuged. Aliquots are taken if necessary. The mixture Is then acidified with formic acid, treated with hydroxylamlne hydrochlorlde- EDTA, and complexed with 3,3 - dlamlnobenzldlne. The pH Is adjusted, and an extraction Is performed with toluene. The absorbance is measured at 420 nm. Recoveries for 100- 10 000 μg selenlum/g premix ranged from 88 to 104%, with an average of 97%. The coefficient of variation ranged from 1.6 to 6.9%, with an average of 4.2%.

Determination of Ethylenethiourea in Grapes and Wine

1985 ◽  
Vol 68 (4) ◽  
pp. 741-745
Author(s):  
Jana Chovancova ◽  
Eva Matisova ◽  
Vojtech Batora
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Electron Capture ◽  
Paper Chromatography ◽  
Capillary Gas Chromatography ◽  
Electron Capture Detection ◽  
Flame Ionization Detection ◽  
Flame Ionization ◽  
Concentration Levels

Abstract Residues of ethylenethiourea (ETU) in grapes and wine were deter- [ mined by capillary gas chromatography and paper chromatography, without a cleanup step, and after derivatization to 5-benzyl-ETU. The ! detection limit was 0.0002 mg/kg for flame ionization detection, 0.008 mg/kg for paper chromatography with photodensitometric evaluation of the detected spot. Results were compared with a generally used GC method specifying electron capture detection of trifluoroacetylated S- benzyl-ETU. The recoveries of ETU in grapes and wine at different j concentration levels were determined. ETU residues were determined J in treated grapes but no residues were detected in wine

Automated Colorimetric Determination of Phenylephrine Hydrochloride in Drug Formulations. II. Collaborative Study

1971 ◽  
Vol 54 (3) ◽  
pp. 600-602
Author(s):  
Michel Margosis
Keyword(s):  
Coefficient Of Variation ◽  
Statistical Evaluation ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
Good Recovery ◽  
Drug Formulations ◽  
Phenylephrine Hydrochloride ◽  
Automated Method

Abstract The automated colorimetric method designed by Lane for the analysis of phenylephrine HCl in drug formulations has been submitted to a collaborative study. Five samples, including 2 with known interferences, were sent to 9 collaborators. The results were subjected to statistical evaluation. These show good recovery and a maximum interlaboratory coefficient of variation of 4.5%. The automated method as evaluated in this study has been adopted as official first action.

scholarly journals The Determination of Tobacco Additives 2nd Report: A Method for Series Analyses of Menthol in Tobacco and Tobacco Products/Zur Bestimmung von Tabakadditiven: 2. Mitteilung: Eine Methode zur serienanalytischen Bestimmung von Menthol in Tabak und Tabakerzeugnissen

1972 ◽  
Vol 6 (3) ◽  
Author(s):  
E. Nesemann ◽  
F. Seehofer
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Quantitative Determination ◽  
Coefficient Of Variation ◽  
Steam Distillation ◽  
Tobacco Products

AbstractThe method used in our laboratories since 1965 for the determination of menthol in tobacco and tobacco products has meanwhile been improved and made suitable for series analyses. Menthol is isolated from the mentholated material to be investigated by steam distillation The distillate containing the menthol in question (dissolved in acetone) is directly subjected to gas chromatography for quantitative determination. The recovery was found to amount to 97 %, the coefficient of variation to 1.45 %, and the detection limit to 0.002 mg of menthol per mI.

Determination of Acidic Herbicides and Related Compounds in Water and Soil by Capillary Gas Chromatography Using a Nitrogen-Phosphorus Detector

1989 ◽  
Vol 72 (2) ◽  
pp. 365-367 ◽  
Author(s):  
Abdul W Ahmed ◽  
Victorin N Mallet ◽  
Michel J Bertrand
Keyword(s):  
Gas Chromatography ◽  
Coefficient Of Variation ◽  
Capillary Gas Chromatography ◽  
Resin Column ◽  
Average Coefficient ◽  
Acidic Herbicides ◽  
Nitrogen Phosphorus Detector ◽  
Related Compounds ◽  
Nitrogen Phosphorus

Abstract Methods are described for the determination of acidic herbicides and related compounds in water and soil. Eight acidic herbicides and related compounds were extracted from water using either dichloromethane or an XAD-2 resin column. The acidic moieties were derivatized with 2-cyanoethyldimethyl(diethyl)aminosilane. The derivatized compounds were separated using capillary gas chromatography and quantitated using a nitrogen-phosphorus detector. Extraction from water using dichloromethane or an XAD-2 resin column resulted in recoveries > 90% at 0.1 ppb with an average coefficient of variation (CV) of 6%. In soils extracted with aqueous acetonitrileacetic acid and partitioned into dichloromethane, recoveries at 500 ppb were > 75% with an average CV of 3.3%. The methods are rapid and there are few interferences.

Colorimetric Determination of Carbaryl in Wettable Formulations

1971 ◽  
Vol 54 (1) ◽  
pp. 128-130
Author(s):  
Eugenio E Vonesch ◽  
Maria H C K de Riveros
Keyword(s):  
Detection Limit ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
Technical Products

Abstract A rapid colorimetric method is described for the determination of carbaryl in technical products and wettable formulations, based on the reaction of carbaryl with diazotized 2,5-dichloroaniline. This reaction is sensitive to 0.1 μg, with a detection limit of 0.2 ppm. Recoveries of pure carbaryl were excellent and analyses of technical products were reproducible.

Capillary Gas Chromatographic Determination of Some Chlorobiphenyls in Eel Fat: Interlaboratory Study

1985 ◽  
Vol 68 (4) ◽  
pp. 756-759
Author(s):  
Louis G M Th Tuinstra ◽  
Arie H Roos ◽  
Geziena A Werdmuller
Keyword(s):  
Gas Chromatography ◽  
Standard Deviation ◽  
Coefficient Of Variation ◽  
Capillary Gas Chromatography ◽  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Analytical Results ◽  
The Mean

Abstract A method for determination of 6 individual chlorobiphenyls in eel fat, based on saponification of the sample and determination with capillary gas chromatography, was studied collaboratively. Eleven laboratories submitted analytical results in duplicate for 6 individual chlorobiphenyls on 2 naturally contaminated eel fat samples. The reproducibility coefficient of variation was about 14% at the 1 mg/kg level for each chlorobiphenyl compound and about 23% at the 0.1 mg/kg level. For each compound, the mean recovery was about 90% with a standard deviation varying from 7 to 9%.

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