Rapid Column Method for Determination of N-Nitrosodimethylamine in Malt

1984 ◽  
Vol 67 (1) ◽  
pp. 20-21
Author(s):  
Donald C Havery ◽  
Gracia A Perfetti ◽  
Fazio Thomas
Keyword(s):  
Coefficient Of Variation ◽  
Vacuum Distillation ◽  
Distillation Method ◽  
Average Recovery ◽  
Column Method ◽  
Elution Method ◽  
Good Agreement

Abstract A rapid column elution method has been developed for the determination of N-nilrosodimethylamine (NDMA) in malt. The average recovery of NDMA added to malt at the 10 ppb level was 87%. When a single malt sample was analyzed 10 times, the NDMA found averaged 8.1 ppb with a coefficient of variation of 3.93%. In a study of 15 malt samples, data obtained by the column elution method were in good agreement with those from a vacuum distillation method.

High Pressure Liquid Chromatographic Determination of Monensin in Feed Premixes

1983 ◽  
Vol 66 (2) ◽  
pp. 284-286
Author(s):  
Thomas D Macy ◽  
Andrew Loh
Keyword(s):  
High Pressure ◽  
Coefficient Of Variation ◽  
Chromatographic Determination ◽  
Hplc Method ◽  
High Pressure Liquid Chromatographic ◽  
Average Recovery ◽  
Bioassay Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high pressure liquid chromatographic (HPLC) method has been developed to determine monensin in feed premixes. The method is simple and rapid. Monensin is extracted with methanol-water and determined in the extracting solution by HPLC. Average recovery for monensin from a 13.2% premix sample was 103% (coefficient of variation (CV), 2.6%) by HPLC and compares with the value of 100% (CV, 3.4%) obtained by the turbidimetric bioassay method.

Determination of Sevin Insecticide Residues in Fruits and Vegetables

1964 ◽  
Vol 47 (2) ◽  
pp. 283-286
Author(s):  
D P Johnson
Keyword(s):  
Fruits And Vegetables ◽  
Collaborative Study ◽  
Colorimetric Determination ◽  
Average Recovery ◽  
Insecticide Residues ◽  
Chromogenic Agent ◽  
Hydrolysis Of ◽  
Concentration Levels ◽  
Good Agreement

Abstract Collaborative study of a method for Sevin insecticide residues was repeated with apples and lettuce as test crops. The method is based on alkaline hydrolysis of Sevin and colorimetric determination of the resulting 1-naphthol with p-nitrobenzenediazonium fluoborate as chromogenic agent. Data from 5 collaborators were in good agreement with an average recovery of 87.8% at 2 concentration levels. It is recommended that the method be adopted as official, first action.

Microbiological Assay of Oxytetracycline in Liquid Supplements

1972 ◽  
Vol 55 (6) ◽  
pp. 1354-1357
Author(s):  
Donald W Clarke
Keyword(s):  
Low Temperature ◽  
Coefficient Of Variation ◽  
Extraction Procedure ◽  
Microbiological Assay ◽  
Official Method ◽  
Average Recovery ◽  
Low Temperature Storage ◽  
Present Official Method ◽  
Temperature Storage

Abstract The extraction procedure of the official final action method for the determination of oxytetracycline in dry feeds, 38.208–38.213, has been modified for the analysis of liquid supplements. Ten g samples were extracted with 50 ml acid-methanol and diluted to 100 ml with the same solvent. Aliquots of the extract prepared according to the modified extraction procedure were assayed by the present official method and gave an average recovery of 100.6% and a coefficient of variation of 6.2% at a medication level of 500 mg/lb. Assays performed on liquid supplements containing oxytetracycline stored for an average of 26 days at 37 and 21°C, and for 37 days at – 4°C showed potency retentions of 21, 80, and 97%, respectively, indicating a need for low-temperature storage prior to analysis.

scholarly journals Kinetic Spectrophotometric Method for the Determination of Ranitidine and Nizatidine in Pharmaceuticals

2002 ◽  
Vol 85 (6) ◽  
pp. 1316-1323 ◽  
Author(s):  
Mohamed I Walash ◽  
Fathalla Belal ◽  
Fawzia Ibrahim ◽  
Mohamed Hefnawy ◽  
Manal Eid
Keyword(s):  
Spectrophotometric Method ◽  
Reaction Pathway ◽  
Kinetic Method ◽  
Fixed Time ◽  
Borate Buffer ◽  
The Other ◽  
Average Recovery ◽  
Kinetic Spectrophotometric ◽  
Good Agreement

Abstract An accurate and simple kinetic method is described for the determination of ranitidine and nizatidine in pure form and in pharmaceuticals. The method is based on the reaction of the compounds with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole in pH 7.4 borate buffer at 60°C for a fixed time of 25 min for both compounds. The absorbance of the reaction product is measured at 495 nm for ranitidine and nizatidine. Calibration graphs were linear over the concentration range of 2–20 μg/mL, with limits of detection of 0.13 (3.7 × 10−7M) and 0.25 μg/mL (7.5 × 10−7M) for ranitidine and nizatidine, respectively. The proposed method was applied successfully to the determination of ranitidine in tablets and ampoules with average recoveries of 100.26 ± 0.69 and 100.29 ± 0.59%, respectively, and to the determination of nizatidine in capsules with an average recovery of 104.26 ± 0.44%. The results obtained are in good agreement with those obtained by the other methods used for comparison. A proposal of the reaction pathway is also presented.

Improved Method for Determination of Light Filth in Chocolate Products

1978 ◽  
Vol 61 (4) ◽  
pp. 996-998
Author(s):  
Marie T Shostak
Keyword(s):  
Adverse Effect ◽  
Coefficient Of Variation ◽  
Mineral Oil ◽  
Improved Method ◽  
Average Recovery

Abstract The recovery of rodent hairs from chocolate has been significantly improved by the introduction of an additional defatting step, substitution of 4 0% isopropanol for water, and substitution of mineral oil-heptane (85+15 ) for heptane in the trapping-off step. These changes have no adverse effect on insect fragment recovery. An average recovery of 9 5 % was obtained for rodent hairs, coefficient of variation 7.9%. Insect fragment recoveries were 100%.

scholarly journals Determination of Oxygen Solubility in NaK-78 by Vacuum Distillation Method

1983 ◽  
Vol 20 (12) ◽  
pp. 1032-1038 ◽  
Author(s):  
Takao SAKAP ◽  
Minoru GUNJI ◽  
Seio MATSUMOTO ◽  
Yoichiro ISHII
Keyword(s):  
Vacuum Distillation ◽  
Oxygen Solubility ◽  
Distillation Method

High-Speed Liquid Chromatographic Determination of Monensin, Narasin, and Salinomycin in Feeds, Using Post-Column Derivatization

1988 ◽  
Vol 71 (3) ◽  
pp. 480-484 ◽  
Author(s):  
Michel R Lapointe ◽  
Huguette Cohen
Keyword(s):  
Ethyl Acetate ◽  
Coefficient Of Variation ◽  
High Speed ◽  
Chromatographic Determination ◽  
Poultry Feed ◽  
Average Recovery ◽  
Animal Feeds ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A high-speed liquid chromatographic (LC) method using post-column derivatization is described for the determination of monensin, narasin, and salinomycin in a variety of animal feeds. The ionophores are extracted with hexane-ethyl acetate (90 + 10). A portion of the sample is evaporated, diluted to a known volume, and analyzed using a 6 cm 3 μm C18 column and an absorbance detector after post-column reaction with vanillin. The method has been applied to poultry and swine feeds with levels of 3-100 ppm added antibiotic. A comparison was also carried out with medicated poultry feed and beef feed lot supplement samples previously analyzed by 2 separate bioassay methods for monensin and salinomycin, respectively. Recoveries for the LC method ranged from 92.1 to 103% with an average recovery of 98.1% and a coefficient of variation of 3.65%.

Collaborative Study of a Spectrophotometric Determination of Ferric, Ferrous, and Total Iron in Drugs by Reaction with α,α′-Dipyridyl

1977 ◽  
Vol 60 (6) ◽  
pp. 1350-1354
Author(s):  
Daniel J Sullivan
Keyword(s):  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Coefficient Of Variation ◽  
Collaborative Study ◽  
Total Iron ◽  
Average Recovery ◽  
Average Coefficient ◽  
Iron Preparation ◽  
Colorimetric Reagent

Abstract A spectrophotometric method for determining Fe2+, Fe3+, and total Fe in drugs has been developed, using α, α′-dipyridyl as the colorimetric reagent. The method is applicable to tablets, elixirs, injectables, and bulk powders. Eight collaborators analyzed a synthetic iron preparation and 7 commercial samples. For the synthetic iron preparation, the average recovery was 100.3% and the coefficient of variation was 1.02%. For 7 commercial samples, the average coefficient of variation was 1.44%. The method has been adopted as official first action.

Liquid Chromatographic Determination of Chlortetracycline Hydrochloride in Ruminant and Poultry/Swine Feeds

1991 ◽  
Vol 74 (5) ◽  
pp. 780-784 ◽  
Author(s):  
David C Holland ◽  
Kent C Faul ◽  
Jose E Roybal ◽  
Robert K Munns ◽  
Wilbert Shimoda
Keyword(s):  
Standard Deviation ◽  
Coefficient Of Variation ◽  
Methylene Chloride ◽  
Chromatographic Determination ◽  
Average Recovery ◽  
Liquid Chromatographic Determination ◽  
Feed Premix ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the determination of chlortetracycline hydrochloride (CTC) in poultry/swine and ruminant feeds in the 10-100 ppm range and in premix. CTC is extracted from ground feed/premix with acidified acetone, and the extract is filtered through a Millex-HV filter or disposable C 18 column. The filtrate Is partitioned with methylene chloride when additional cleanup is necessary. A Nova-Pak C 18 column Is used for LC separation with determination at 370 nm. The average recovery of CTC from premix was 95% with a standard deviation (SD) of 1.70 and a coefficient of variation (CV) of 1.79%. The overall average recovery from feeds was 77% with an SO of 3.18 and a CV of 4.10%.

Determination of Sterigmatocystin in Corn and Oats by Gel Permeation and High-Pressure Liquid Chromatography

1976 ◽  
Vol 59 (5) ◽  
pp. 966-970
Author(s):  
Michael E Stack ◽  
Stanley Nesheim ◽  
Nathan L Brown ◽  
Albert E Pohland
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
High Pressure Liquid Chromatography ◽  
Coefficient Of Variation ◽  
Gel Permeation Chromatography ◽  
Automatic Instrument ◽  
Average Recovery ◽  
Ultraviolet Detector ◽  
Gel Permeation

Abstract Corn and oats samples are extracted with acetonitrile-water, followed by partition of the extract against hexane, transfer to chloroform, and elution from a silica gel column. The extract is purified by gel permeation chromatography on an automatic instrument. Reverse phase high-pressure liquid chromatography, using a 254 nm ultraviolet detector and 0.1M KH2PO4-acetonitrile (7+5) as the mobile phase, is used for quantitation. The average recovery from 6 samples of corn to which 0, 25, 50, and 100 μg sterigmatocystin/kg had been added was 59%, with a coefficient of variation of 8.4%. The average recovery from oats fortified at the same levels was 74%, with a coefficient of variation of 12%. A confirmation procedure based on hemiacctal derivative formation on a thin layer chromatographic plate is also described.

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