Liquid Chromatographic Determination of Dicofol in Kelthane Formulations: Collaborative Study

1986 ◽  
Vol 69 (4) ◽  
pp. 714-720
Author(s):  
Alan M Rothman ◽  
◽  
A Ausari ◽  
O O Bennett ◽  
E J Blusiewicz ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Standard Deviation ◽  
High Resolution ◽  
Mobile Phase ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
In Series ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was used to determine p,p'- and o,p'-isomers of dicofol AI (active ingredient) in Kelthane® EC and MF formulations. Samples are dissolved in methanol and AI components and impurities are separated on a high resolution C8 column in series with a short C18 guard column, with a methanol-water-acetic acid mobile phase. Cleaned samples are directly injected into the LC system and are monitored at 254 nm. Twelve collaborators submitted results on 5 samples. Using 95% confidence criteria, the average total standard deviation of the total AI across all samples was 2.82%. The method has been adopted official first action.

Liquid Chromatographic Determination of Carbofuran in Technical and Formulated Products: Collaborative Study

1986 ◽  
Vol 69 (5) ◽  
pp. 915-918
Author(s):  
Edward J Kikta ◽  
◽  
E Bane ◽  
A Burns ◽  
A Christensen ◽  
...  
Keyword(s):  
Mobile Phase ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Data Sets ◽  
Matched Pairs ◽  
Reverse Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for the analysis of technical and formulated carbofuran samples was evaluated in a collaborative study. Carbofuran is determined by reverse phase LC, using a water-methanol mobile phase and acetophenone as internal standard, and detected at 280 nm. Twelve samples, 5 formulations and technical matched pairs, were analyzed by 17 collaborating laboratories. Accuracy and variability of results are typical of large LC data sets. The method has been adopted official first action.

Liquid Chromatographic Determination of Coumarin Anticoagulants in Tablets: Collaborative Study

1987 ◽  
Vol 70 (5) ◽  
pp. 834-836
Author(s):  
Ella S Moore
Keyword(s):  
Mobile Phase ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Content Uniformity ◽  
Photometric Detection ◽  
Warfarin Sodium ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for the determination of coumarin anticoagulants in tablets was collaboratively studied by 7 laboratories. The method uses an octadecylsilane-bonded microparticulate column, tetrahydrofuran-methanol-water-acetic acid mobile phase, and photometric detection at 311 nm. Each collaborator received samples of warfarin sodium, phenprocoumon, and dicumarol as a synthetic composite and as commercial individual and composited tablets. Pooled average assay values for synthetic and commercial tablet samples of warfarin sodium were 101.6 and 99.5%, respectively, with a combined reproducibility SD of 2.38% (CV = 2.37%) and combined repeatability SD of 1.49% (CV = 1.49%). Pooled average (SD) assay values for dicumarol and phenprocoumon commercial samples were 98.0 (2.27) and 101.3% (4.00), respectively. The content uniformity determinations of 2 mg warfarin sodium and 25 mg dicumarol tablets indicated average tablet contents (range) of 99.5% (91.0-116.0) and 98.0% (89.8-108.8), respectively. The method has been approved interim official first action

Isolation, Purification, and Liquid Chromatographic Determination of Stilbene Phytoalexins in Peanuts

1995 ◽  
Vol 78 (5) ◽  
pp. 1177-1182 ◽  
Author(s):  
Victor S Sobolev ◽  
Richard J Cole ◽  
Joe W Dorner ◽  
Boris Yagen
Keyword(s):  
Acetic Acid ◽  
Silica Gel ◽  
Mobile Phase ◽  
High Speed ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Phase Partition ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for determination of stilbene phytoalexins (SPs) in peanuts has been developed. SPs were extracted with acetonitrile–water (90 + 10, v/v) by high-speed blending. An aliquot of extract was applied to a minicolumn packed with AI2O3–ODS (C18) mixture and eluted with acetonitrile-water (90 + 10, v/v). Eluate was evaporated under nitrogen, and residue was dissolved in LC mobile phase. SPs in an aliquot of purified extract were quantitated by normal-phase partition LC on silica gel with n-heptane–2-propanol–water–acetonitrile–acetic acid (1050 + 270 + 17 + 5 + 1, v/v) as mobile phase. Recoveries of SPs [frans-4-(3-methyl-but-1-enyl)-3,5,4′-trihy-droxystilbene (trans-arachidin-3; t-Ar-3), trans-3-isopentadienyl-4,3′,5′-trihydroxystilbene (t-IPD), and trans-3,5,4′-trihydroxystilbene (trans-resveratrol; t-Res)] from peanuts spiked at 300 ppb were 96.05 ± 2.8%. Limits of quantitation for t-Ar-3 and t-IPD were about 100 ppb. t-Ar-3, t-IPD, and t-Res were found in all parts of the peanut plant as major SPs produced in response to fungal invasion.

Collaborative Study of the Gas-Liquid Chromatographic Determination of Bromoxynil Octanoate in Formulations

1978 ◽  
Vol 61 (5) ◽  
pp. 1158-1162
Author(s):  
Laurence J Helfant
Keyword(s):  
Standard Deviation ◽  
Acid Ester ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Improved Method ◽  
Liquid Chromatographic Determination ◽  
Chlorophenoxyacetic Acid ◽  
Liquid Chromatographic

Abstract The determination of bromoxynil octanoate by a gas-liquid chromatographic (GLC) method with di-n-butylphthalate as internal standard was subjected to testing by 10 collaborators. The standard deviation for bromoxynil octanoate and bromoxynil octanoate-MCPA (2-methyI- 4-chlorophenoxyacetic acid) ester formulations averaged 0.6%. While the deviation indicates that the method is statistically sound, the results were dependent upon the efficiency of the GLC column. Therefore, it is recommended that the method be subjected to continued study to further determine the GLC conditions necessary for improved method reliability.

Gas-Liquid Chromatographic Determination of Bromoxynil Octanoate: Collaborative Study

1979 ◽  
Vol 62 (6) ◽  
pp. 1215-1219
Author(s):  
Laurence J Helfant ◽  
◽  
J Audino ◽  
G S Grimes ◽  
J J Karr ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Systematic Errors ◽  
Elution Time ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The assay of bromoxynil octanoate by a gasliquid chromatographic (GLC) procedure with din-n-butylphthalate as the internal standard was previously subjected to collaboration. The method had a standard deviation of 0.6% but results varied according to the complexity of the formulaation being tested. To reduce the systematic errors of the method, the internal standard was changed to n-docosane. The change in elution time of the marker simplified the chromatogram and reduced the standard deviation of the study to 0.3%. The revised method has been adopted as official first action for determining bromoxynil octanoate.

High Pressure Liquid Chromatographic Determination of Bacitracin in Premix Feeds and Finished Feeds: Collaborative Study

1982 ◽  
Vol 65 (5) ◽  
pp. 1178-1185 ◽  
Author(s):  
John B Gallagher ◽  
Paul W Love ◽  
Linda L Knotts ◽  
◽  
M Allred ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Chromatographic Technique ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Repeatability Standard Deviation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic technique for the determination of bacitracin in finished feeds and premix feeds consists of an isocratic reverse phase, ion-suppressed technique. The chromatography can be completed in less than 25 min. In a collaborative study involving 9 laboratories and 3 samples of bacitracin methylene disalicylic acid and 3 samples of bacitracin zinc premixes covering the range of 10-50 g/lb, the repeatability standard deviation was 0.55, and the reproducibility standard deviation was 1.35. The average recovery of the bacitracin was 102.0%. The method has been adopted official first action for bacitracin in premix feeds.

Liquid Chromatographic Determination of Primidone in Tablets: Collaborative Study

1985 ◽  
Vol 68 (1) ◽  
pp. 85-87 ◽  
Author(s):  
Stanley E Roberts
Keyword(s):  
Quantitative Determination ◽  
Mobile Phase ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Six laboratories collaboratively studied a liquid chromatographic (LC) method for the quantitative determination of primidone in tablets. Two lots each of commercially prepared 50 and 250 mg tablets and 2 authentic mixtures, at 50 and 250 mg levels, were sent to each collaborator. Samples were dissolved in the mobile phase, filtered, and injected into the chromatograph. Average recoveries for the 8 samples ranged from 97.5 to 101.2%, and coefficients of variation ranged from 0.53 to 3.01%. The LC method has been adopted interim official first action.

Liquid Chromatographic Determination of Naproxen and Related Compounds in Raw Materials

1990 ◽  
Vol 73 (6) ◽  
pp. 902-904 ◽  
Author(s):  
David B Moir ◽  
Normand Beaulieu ◽  
Norman M Curran ◽  
Edward G Lovering
Keyword(s):  
Acetic Acid ◽  
Mobile Phase ◽  
Raw Materials ◽  
Chromatographic Determination ◽  
Assay Method ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Related Compounds

Abstract A liquid chromatographic (LC) method for determination of naproxen and 8 known related compounds has been developed. The lower limit of quantitation of the related compounds In the drug Is 0.04% or less for all compounds; the precision of the drug assay method Is ca 0.4%. The method uses an octadecylsllyl column, a mobile phase of 1 % acetic acid (v/v)-methanol-acetonitrlle (48 + 22 + 30, v/v/v) and detection at 231 nm.

Liquid Chromatographic Determination of Acetic Acid in Foods

1984 ◽  
Vol 67 (5) ◽  
pp. 885-887
Author(s):  
Samy H Ashoor ◽  
Jim Welty
Keyword(s):  
Acetic Acid ◽  
Flow Rate ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Uv Detector ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method has been developed for the determination of acetic acid in vinegar and other foods. The LC system includes an Aminex HPX-87H column and a UV detector set at 210 nm. The mobile phase is 0.009N H2S04 at a flow rate of 0.7 mL/min. The method is simple and specific for acetic acid. Recoveries of acetic acid from a variety of products ranged from 93.3 to 102% with coefficients of variation from 2.4 to 4.6%.

Gas-Liquid Chromatographic Determination of Melengestrol Acetate in Cattle Feed Supplements: Collaborative Study

1980 ◽  
Vol 63 (3) ◽  
pp. 425-443
Author(s):  
Raymond A Davis ◽  
D Dal Kratzer ◽  
Shu Geng ◽  
◽  
S L Barney ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Sample Standard Deviation ◽  
Cattle Feed ◽  
Melengestrol Acetate ◽  
Feed Supplements ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract The assay for melengestrol acetate (MGA) in cattle feed supplements was the subject of a collaborative study using 6 laboratories. Two feed formulations were each fortified with 0, 0.0625, 0.125, 0.500, 1.00, and 1.50 mg MGA/lb of supplement, and each laboratory assayed 4 samples of each level of each formulation by electron capture gas chromatography after liquid-liquid extraction of each sample followed by solvent partition and column chromatography cleanup procedures. Overall recovery was 83.2% with a pooled within-laboratory sample-to-sample standard deviation of 9.5%. This includes the variability due to formulation, batches, days, levels of MGA, samples, and their interactions. Including the collaborators as a source of variance results in an overall standard deviation of 15.0%. The major sources of variability were associated with collaborator, formulation, and level of MGA. Lower than expected recoveries were attributed to difficulty in recovering MGA from samples containing concentrations of MGA below the range of the method and the inadvertent substitution by some laboratories of ethanol-free chloroform for the ethanol-containing reagent grade chloroform specified in the methodology. On the basis of the collaborative results, the method has been adopted as official first action for MGA in cattle feed supplements at concentrations from 0.125 to 1.00 mg MGA/lb.

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