Liquid Chromatographic Determination of Desfuroylceftiofur Metabolite of Ceftiofur as Residue in Cattle Plasma

1990 ◽  
Vol 73 (1) ◽  
pp. 26-30 ◽  
Author(s):  
Prem S Jaglan ◽  
Byron L Cox ◽  
Thomas S Arnold ◽  
Marc F Kubicek ◽  
Dorothy J Stuart ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Mobile Phase ◽  
Ammonium Acetate ◽  
Plasma Sample ◽  
Chromatographic Determination ◽  
Phase Flow ◽  
Mobile Phase Flow Rate ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method has been developed for the determination of the desfuroylceftiofur metabolite of ceftiofur as a residue in the plasma of animals. Plasma sample in 0.1 M pH 8.7 phosphate buffer containing dithioerythritol is Incubated under nitrogen for 15 min at 50°C. The sample is centrifuged, charged to a C18 cartridge, and washed with 0.1M ammonium acetate. The desfuroylceftiofur residue on the cartridge Is derivatized by adding 0.1M ammonium acetate containing iodoacetamide and letting the cartridge stand in the dark for 30 min. The cartridge is then drained and rinsed, and the desfuroylceftiofur acetamide is eluted with methanol. The mixture is evaporated to dryness, dissolved in pH 10.6 sodium hydroxide, and charged to a SAX cartridge. The derivative is eluted with 2% acetic acid, reduced In volume, and dissolved in mobile phase for liquid chromatography. The LC system includes a C8 column and guard cartridge with UV detection at 254 nm. The gradient mobile phase (flow rate 1 mL/mln) is 0.01M pH 5 ammonium acetate programmed to 29 % methanol-water (60 + 40) in 25 min. Recoveries were 90-100% with a sensitivity of 0.1 ppm or less. The procedure has been applied to the plasma of cattle, rats, horses, pigs, and dogs.

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.

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 Tenuazonic Acids in Tomato Paste

1980 ◽  
Vol 63 (3) ◽  
pp. 612-621 ◽  
Author(s):  
Peter M Scott ◽  
Shriniwas R Kanhere
Keyword(s):  
Mobile Phase ◽  
Ammonium Acetate ◽  
Methylene Chloride ◽  
Chromatographic Determination ◽  
Gas Liquid Chromatography ◽  
Tenuazonic Acid ◽  
Tomato Paste ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Tenuazonic acid is a mycotoxin produced by Alternaria alternata (A. tenuis) occurring in isolates from tomato. Several liquid chromatographic (LC) systems were compared for suitability in analyzing tomato pastes for tenuazonic acid. Tenuazonic acid was extracted from tomato paste with methanol and n-hexane and was partitioned into methylene chloride from the aqueous methanol following acidification. It was further partitioned into 5% NaHCO3, acidified, and reextracted with methylene chloride. LC separation of tenuazonic acid from interferences was best on a C12- dien (4-dodecyldiethylenetriamine) loaded C18 reverse phase column with a mobile phase containing C12-dien, Zn(II), and ammonium acetate, or on a tetraalkylammonium anion exchange columnat pH 7.5. Two isomeric tenuazonic acids could be partially separated in the C12-dien/metal system using acetonitrile in the mobile phase. Amounts of standard tenuazonic acid as low as 2–5 ng could be detected by UV absorbance at 280 nm. Recoveries of tenuazonic acid or isotenuazonic acid added to tomato paste at levels of 0.4–10 μg/g were 67–94%. Small amounts of tenuazonic acid were detected in several commercial tomato pastes at levels of 0.01–0.1 μg/g. Gas liquid chromatography/ mass spectrometric (GLC/MS) single ion monitoring showed that both isomers were present.

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%.

Liquid Chromatographic Determination of the Anticoccidial Drug Halofuginone Hydrobromide in Eggs

1995 ◽  
Vol 78 (1) ◽  
pp. 37-40 ◽  
Author(s):  
David C Holland ◽  
Robert K Munns ◽  
Jose E Roybal ◽  
Jeffrey A Hurlbut ◽  
Austin R Long
Keyword(s):  
Standard Deviation ◽  
Mobile Phase ◽  
Ammonium Acetate ◽  
Chromatographic Determination ◽  
Free Base ◽  
Average Recovery ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the determination of 5-100 ppb halofuginone hydrobromide (HFG) in eggs. HFG as the free base is extracted from eggs with ethyl acetate. The extract is cleaned up on an acidic Celite 545 column. A Waters C18 column is used for LC separation with UV determination at 243 nm. The isocratic mobile phase is a mixture of water-acetonitrile-ammonium acetate buffer (12 + 5 + 3) and acetic acid. The interassay average recovery from eggs was 90.4%, with a standard deviation of 5.11 and a relative standard deviation of 5.65%.

Liquid Chromatographic Determination of Methyldopa and Methyldopa-Thiazide Combinations in Dosage Forms

1983 ◽  
Vol 66 (6) ◽  
pp. 1436-1442
Author(s):  
Susan Ting
Keyword(s):  
Acetic Acid ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Dosage Forms ◽  
Reverse Phase ◽  
Relative Standard ◽  
Liquid Chromatographic Determination ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method, using a reverse phase C18 column, an acetic acid-methanol-water mobile phase, and detection at 280 nm, was developed for the determination of methyldopa in tablets and oral suspensions and combinations of methyldopa with hydrochlorothiazide or chlorothiazide in tablets. A mixture of these 3 drugs was resolved in <8 min. Detector responses were linear for the following amounts (mg/mL) of drug injected: methyldopa 0.031-0.393, chlorothiazide 0.019-0.114, and hydrochlorothiazide 0.004-0.083. Recoveries from commercial dosage forms ranged from 99.1 to 100.9% for methyldopa, 99.2-100.4% for chlorothiazide, and 100.0-101.2% for hydrochlorothiazide. Replicate injections of methyldopa, chlorothiazide, and hydrochlorothiazide standard preparations alone or in combination gave overall relative standard deviations of <1.6% (n = 10). The results for methyldopa tablets by the proposed method were in agreement with those obtained by the USP XX method. The LC method detected as little as 0.6 μg 3-O-methylmethyldopa/mL and 0.5 μg 4-amino-6- chloro-l,3-benzenedisulfonamide/mL, which are sometimes found as contaminants of methyldopa and thiazides, respectively, and resolved methyldopa from its methyldopa glucose adduct, a substance found in methyldopa oral suspensions.

Reverse Phase Liquid Chromatographic Determination of Chlorophacinone and Diphacinone in Bait Formulations

1982 ◽  
Vol 65 (4) ◽  
pp. 927-929
Author(s):  
Brian R Bennett ◽  
Gregory S Grimes
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Target Concentration ◽  
External Standard ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract Chlorophacinone and diphacinone are extracted at the 0.005% level from grain or paraffinized baits with glacial acetic acid. The target concentration is 0.01 mg/mL. The filtered supernate is chromatographed on a Partisil PXS ODS10/25 liquid chromatography column with premixed and degassed glacial acetic acid-tetrahydrofuran-water (14 + 2 + 9) and detected at 288 nm. The concentration is calculated by using an external standard. The recovery from spiked samples averaged 96.6% for both analytes. The response is linear from 0.001 to 0.040 mg/mL. The coefficient of variation of within-day replicates ranged from 1.1 to 2.5%.

Improved liquid-chromatographic determination of haloperidol in plasma.

1984 ◽  
Vol 30 (7) ◽  
pp. 1228-1230 ◽  
Author(s):  
A K Dhar ◽  
H Kutt
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Room Temperature ◽  
Internal Standard ◽  
Isoamyl Alcohol ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract This method for determination of haloperidol in plasma is based on "high-performance" isocratic liquid chromatography with the use of a C8 bonded reversed-phase column at room temperature. Haloperidol and the internal standard (chloro-substituted analog) are extracted from alkalinized plasma into isoamyl alcohol/heptane (1.5/98.5 by vol) and back-extracted into dilute H2SO4. The aqueous phase is directly injected onto the column. The mobile phase is a 30/45/25 (by vol) mixture of phosphate buffer (16.5 mmol/L, pH 7.0), acetonitrile, and methanol. Unlike other liquid-chromatographic procedures for haloperidol, commonly used psychotropic drugs do not interfere. Analysis can be completed within an hour. The procedure is extremely sensitive (1.0 microgram/L) and is well reproducible (CV 5.6% for a 2.5 micrograms/L concentration in plasma).

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