Liquid Chromatographic Determination of Propyl Paraben in Cigarette Filler

1988 ◽  
Vol 71 (6) ◽  
pp. 1115-1117
Author(s):  
Jorge I CastaÑo ◽  
Francisco J Palacio ◽  
Luis R Vargas
Keyword(s):  
Chromatographic Determination ◽  
Cigarette Tobacco ◽  
Propyl Paraben ◽  
Coefficients Of Variation ◽  
Water Ph ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Cut Tobacco ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method for the quantitative determination of propyl paraben in cigarette tobacco filler has been developed. Propyl paraben is extracted from cigarette tobacco filler with acetonitrile and further purified using a silica Sep-Pak® cartridge and ethyl acetate-petroleum ether (1 + 4) as eluting solvent. The purified extracts are analyzed by reverse-phase liquid chromatography using buffered water (pH 4)-acetonitrile (65 + 35) as mobile phase, with UV detection at 254 nm. Cut tobacco samples were fortified with 100 and 200 ppm propyl paraben. Average recoveries (N = 5) of propyl paraben were 98 and 94%, respectively, with coefficients of variation less than 4%.

Normal Phase Liquid Chromatographic Determination of Pyrethrins in Formulations

1985 ◽  
Vol 68 (6) ◽  
pp. 1134-1136 ◽  
Author(s):  
Rodney J Bushway
Keyword(s):  
Chromatographic Determination ◽  
Solvent System ◽  
Elution Time ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Pesticide Formulations ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method has been developed to quantitate pyrethrins in pesticide formulations. Samples were dissolved in tetrahydrofuran (THF) and injected onto an amino column with a solvent system of hexane-nonstabilized THF (90 + 10) at a flow rate of 1.5 mL/min. Detection was monitored at 240 nm and 0.4 AUFS. Total elution time was 7 min. Twelve products varying in concentration from 0.05 to 3.75% and formulated with numerous other ingredients were analyzed. Percent coefficients of variation ranged from 1.39 to 9.68 with the majority less than 5.00. Although piperonyl butoxide and Noctyl bicycloheptene dicarboximide (MGK 264) were not quantitated, neither interfered with the pyrethrin analysis

Liquid Chromatographic Determination of Carhadox in Complete Feeds, Premixes, and Concentrates: Interlaboratory Study

1988 ◽  
Vol 71 (3) ◽  
pp. 484-490
Author(s):  
René M L Aerts ◽  
Geziena A Werdmuller
Keyword(s):  
Chromatographic Determination ◽  
Interlaboratory Study ◽  
Alumina Column ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
A Minor ◽  
Liquid Chromatographic ◽  
Feed Samples

Abstract A liquid chromatographic (LC) method previously published for the determination of carbadox in finished feeds and premixes was slightly modified and tested in an interlaboratory study. The feed samples are extracted with methanol-acetonitrile (50 + 50) after wetting with water. The extracts are purified over a short alumina column. An aliquot of the eluate is analyzed with reverse phase liquid chromatography with ultraviolet detection. Before the actual interlaboratory study, a prestudy with 2 familiarization feed samples was performed. For the interlaboratory study, 2 series of meal and pelleted samples were prepared with carbadox from different suppliers. Eight collaborating laboratories received 6 feed samples previously milled and ground and 4 pelleted samples which had to be ground by the collaborator's in-house method. Collaborators also received 3 carbadox concentrates (about 10% w/w) and 4 premix samples derived from the concentrates (about 1% w/w). Coefficients of variation under reproducibility conditions were 8.3% for meal samples and 4.9% for pellets. A minor but significant effect was noted for the influence of pelleting temperature on the carbadox content. A minor and insignificant effect was observed for the influence of the milling and grinding procedure on the carbadox content. Alumina cleanup of 1% premixes was not essential, although the resulting chromatograms were cleaner. A slight difference in reproducibility was observed with concentrates (10%) when 0.2 or 0.5 g sample size was used, although the average carbadox concentration found was the same. For premixes and concentrates, coefficients of variation under reproducibility conditions were low, ranging from 2.9 to 7.5%.

Liquid Chromatographic Determination of Sulfamethazine in Feeds

1988 ◽  
Vol 71 (5) ◽  
pp. 1054-1056 ◽  
Author(s):  
Joel E Houglum ◽  
Richard D Larson ◽  
Rose M Neal
Keyword(s):  
Colorimetric Method ◽  
Chromatographic Determination ◽  
Tetramethylammonium Chloride ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Feed Samples

Abstract A reverse-phase liquid chromatographic method for the assay of sulfamethazine (SMZ) in feeds is described. Feed samples are extracted with 50% methanol solution, centrifuged, filtered, and diluted when necessary, and chromatographed on a C-18 column. Samples are eluted with a mobile phase of 20% methanol and 80% of a solution containing acetic acid and tetramethylammonium chloride. The average recovery from spiked samples was 97.2% with a coefficient of variation of 1.2%. Linearity was very good (correlation coefficient 0.9997). Within-day and between-day coefficients of variation averaged 1.3 and 2.6%, respectively. The results for samples assayed by this method compared closely with the results from the same extracts assayed by the AOAC colorimetric method

Liquid Chromatographic Determination of Hydrocortisone in Bulk Drug Substance and Tablets: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 218-221 ◽  
Author(s):  
Milda J Walters ◽  
◽  
N Falcone ◽  
K G Hanel ◽  
E H Jefferson ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Chromatographic Determination ◽  
Normal Phase ◽  
Drug Substance ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Bulk Drug ◽  
Liquid Chromatographic

Abstract A normal phase liquid chromatographic (LC) method for determining the hydrocortisone content of bulk drug substance, tablet composites, and individual tablets was subjected to a collaborative study by 6 laboratories. The results showed a mean recovery of 98.5% for an authentic tablet formulation and reproducibility coefficients of variation of 0.97, 1.6, and 2.7% for bulk drug substance, tablet composites, and individual tablets, respectively. Infrared (IR) and thin layer chromatographic (TLC) identification tests, also included in the collaborative study, were satisfactory. The LC method for determining hydrocortisone in bulk drug substance, tablet composites, and individual tablets, with IR and TLC identification, has been adopted official first action.

Simultaneous Liquid Chromatographic Determination of Some Tetracyclines in Serum

1986 ◽  
Vol 69 (5) ◽  
pp. 760-762
Author(s):  
Krystyna Tyczkowska ◽  
Arthur L Aronson
Keyword(s):  
Molecular Weight ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Molecular Weight Cutoff ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A sensitive liquid chromatographic method has been developed for the simultaneous determination of oxytetracycline, minocycline, tetracycline, and doxycycline in serum. A serum sample is vortex-mixed with a solution of mobile phase for tetracyclines and 2% (v/v) phosphoric acid. The mixture is filtered using a 30 000 molecular weight cutoff microseparation tube which separates high-molecular-weight solutes following low-speed centrifugation. Tetracyclines are separated from other serum components by reverse phase liquid chromatography (LC) with buffered methanol mobile phase. Ultraviolet absorbance of the column effluent is monitored at 267 nm. Concentrations as low as 0.2 μg/mL of tetracyclines in serum are quantitatable, with recoveries from 76.2 to 102.6% and coefficients of variation from 2.69 to 5.36%. The method has been tested in bovine, porcine, equine, caprine, ovine, canine, feline, and avian (turkey) serum.

Liquid Chromatographic Determination of Prednisolone in Tablets and Bulk Drugs: Interlaboratory Study

1984 ◽  
Vol 67 (4) ◽  
pp. 674-676
Author(s):  
James F Brower
Keyword(s):  
Chromatographic Determination ◽  
Ethylene Dichloride ◽  
Drug Substances ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Bulk Drug ◽  
Liquid Chromatographic ◽  
Composite Samples

Abstract A normal phase liquid chromatographic (LC) method for the determination of prednisolone in tablets and bulk drugs was studied by 7 analysts. An LC system, consisting of a methanol-water-ethylene dichloride- acetic acid mobile phase and a silica column, was used to analyze bulk drugs, individual tablets, and composite samples. Analysts were supplied with 16 samples, including simulated formulations, composites of commercial tablets, intact tablets, and bulk drug substances. Results agreed with those obtained by the author. The coefficients of variation of the analysts' results ranged from 1.34% for bulk drugs to 2.14% for tablet composites. The LC method is suggested as an alternative to the official AOAC and USP XX blue tetrazolium colorimetric methods.

Simultaneous Liquid Chromatographic Determination of Rotenone and Pyrethrins in Formulations

1985 ◽  
Vol 68 (3) ◽  
pp. 580-582
Author(s):  
Rodney J Bushway ◽  
Harold Johnson ◽  
Donald W Scott
Keyword(s):  
Mobile Phase ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Coefficients Of Variation ◽  
Pesticide Formulations ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Inactive Ingredients ◽  
Liquid Chromatographic

Abstract This paper describes a reverse phase liquid chromatographic (LC) method to simultaneously determine rotenone and pyrethrins in pesticide formulations. The mixed standards along with the formulations were accurately weighed to contain approximately 200 (μg rotenone and 150 (μg pyrethrins/mL. Stabilized tetrahydrofuran was used to dissolve all substances. An aliquot was injected into the LC system equipped with a Zorbax ODS column, and chromatographed with a mobile phase of acetonitrile-water (70 + 30). Rotenone and the pyrethrins were monitored at 240 nm and 0.4 AUFS. Retention times for rotenone, pyrethrin II, and pyrethrin I were approximately 7, 11.5, and 25.5 min, respectively. For 3 different formulations analyzed 6 times each, the percent coefficients of variation were all < 3. This method is also applicable to products containing either rotenone or pyrethrins. No significant interferences were observed from the inactive ingredients of the formulations at the concentrations added.

Liquid Chromatographic Determination of Aflatoxins in Feedstuffs Containing Citrus Pulp

1988 ◽  
Vol 71 (5) ◽  
pp. 957-961 ◽  
Author(s):  
Walter E Paulsch ◽  
Eric A Sizoo ◽  
Hans P Van Egmond
Keyword(s):  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Citrus Pulp ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Postcolumn Derivatization

Abstract A liquid chromatographic (LC) method was developed for the determination of aflatoxins in feedstuffs containing citrus pulp. The feedstuff sample is extracted with chloroform, followed by Sep-Pak Florisil cartridge cleanup and Sep-Pak C18 cartridge cleanup. The final eluate (water-acetone, 85 + 15, v/v) is submitted to reverse-phase liquid chromatography with water-methanol-acetonitrile (130 + 70 + 40, v/v/v) as mobile phase and postcolumn derivatization with iodine. Citrus components are removed from the extract efficiently. The limit of detection for aflatoxin B1 is< 1 μg/kg. Other aflatoxins can also be detected and measured. Recoveries of aflatoxins B1 B2, G,1 and G2 for dairy rations spiked at 13, 5, 10, and 4 μg/kg were 87, 86, 81, and 82%, respectively. Corresponding coefficients of variation were 3.1, 3.6, 5.2, and 3.8%, respectively.

Liquid Chromatographic Determination of Zoalene in Medicated Feeds

1984 ◽  
Vol 67 (5) ◽  
pp. 861-862 ◽  
Author(s):  
John Morawski ◽  
Glenn Kyle
Keyword(s):  
Colorimetric Method ◽  
Chromatographic Determination ◽  
Activated Alumina ◽  
Reverse Phase ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Aoac Official ◽  
Liquid Chromatographic ◽  
Medicated Feeds

Abstract A rapid, reliable separation and quantitation of zoalene (3,5-dinitroo-toluamide) from feeds is accomplished by using reverse phase liquid chromatography (LC) and ultraviolet detection. An extraction technique which is similar to the present AOAC official colorimetric method is used before chromatographic analysis. This extraction is followed by an activated alumina cleanup and LC to separate zoalene from feed matrix. The methodology was applied to a variety of spiked feed matrices, and yielded good recoveries. Liquid chromatographic results were shown to correlate with colorimetric determinations.

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