Determination of Neomycin in Animal Tissues, Using Ion-Pair Liquid Chromatography with Fluorometric Detection

1985 ◽  
Vol 68 (1) ◽  
pp. 29-36
Author(s):  
Badar Shaikh ◽  
Edward H Allen ◽  
John C Gridley
Keyword(s):  
Mobile Phase ◽  
Potassium Phosphate ◽  
Internal Standard ◽  
Ion Pair ◽  
Fluorometric Detection ◽  
Animal Tissues ◽  
Potassium Phosphate Buffer ◽  
Reverse Phase ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method is described for the determination of neomycin in animal tissues. Tissues are homogenized in 0.2M potassium phosphate buffer (pH 8.0); the homogenate is centrifuged, and the supernate is heated to precipitate the protein. The heat-deproteinated extract is acidified to pH 3.5-4 and directly analyzed by LC. The LC method consists of an ion-pairing mobile phase, a reverse phase ODS column, post-column derivatization with o-phthalaldehyde reagent, and fluorometric detection. The LC method uses paromomycin as an internal standard, and separates neomycin from streptomycin or dihydrostreptomycin because they have different retention times. The LC column separates neomycin in 25 min; the detection limit is about 3.5 ng neomycin. The overall recovery of neomycin from kidney tissues spiked at 1-30 ppm was 96% with a 9.0% coefficient of variation. The method was also applied to muscle tissue.

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.

scholarly journals Determination of Ceftriaxone in Cerebrospinal Fluid by Ion-Pair Liquid Chromatography

2005 ◽  
Vol 88 (2) ◽  
pp. 436-439 ◽  
Author(s):  
Marta de Diego Glaría ◽  
Gloria Godoy Moscciati ◽  
Ricardo Godoy Ramos
Keyword(s):  
Cerebrospinal Fluid ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
Tetrabutylammonium Bromide ◽  
Internal Standard ◽  
Ion Pair ◽  
Deionized Water ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic

Abstract An ion-pair liquid chromatographic assay was developed and validated for the determination of ceftriaxone in cerebrospinal fluid. Chromatographic separation was achieved on a C18 column (125 × 4 mm, 5 μm) with detection at 270 nm, a 1 mL/min flow rate and a 50 μL loop. The mobile phase consisted of 300 mL acetonitrile, 50 mL 0.1M phosphate buffer (pH 7.4), 3.2 g tetrabutylammonium bromide as the ion-pairing agent, and dilution with distilled deionized water to 1 L. Cephradine was used as the internal standard. The assay was linear for ceftriaxone concentrations of 0.5–50 μg/mL. The coefficients of variation for precision were <4.61%. The accuracy ranged from 96.07 to 102.42%. The detection and quantitation limits were 0.019 and 0.065 μg/mL, respectively. This method was used to quantify ceftriaxone in the cerebrospinal fluid of children with meningitis. The results showed that the method described here is useful for the determination of ceftriaxone in cerebrospinal fluid.

Liquid Chromatographic Determination of Clobetasone-17-Butyrate in Ointments

1990 ◽  
Vol 73 (6) ◽  
pp. 893-895 ◽  
Author(s):  
Ajay G Patel ◽  
Ramanbhai B Patel ◽  
Mukeshbhai R Patel
Keyword(s):  
Sodium Salt ◽  
Mobile Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Reverse Phase ◽  
Reverse Phase Column ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Phase Column

Abstract A liquid chromatographic (LC) method has been developed for determination of clobetasone-17-butyrate In ointment using clobetasone propionate as an internal standard. Separation was carried out on a C18 reverse-phase column using water-methanol as a mobile phase. Methylparaben and propylparaben (both sodium salt) used as preservatives did not Interfere with separation. Compounds are detected photometrically at 235 nm. Mean assay results for 0.05% commercial ointments were 100.36% (n = 5). Mean recovery of clobetasone-17-butyrate added to commercial ointment was 99.89%.

Liquid Chromatographic Determination of Fluorescent Derivatives of Six Sulfonamides in Bovine Serum and Milk

1995 ◽  
Vol 78 (3) ◽  
pp. 674-678 ◽  
Author(s):  
Chin-En Tsai ◽  
Fusao Kondo
Keyword(s):  
Bovine Serum ◽  
Potassium Phosphate ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Fluorometric Detection ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Derivatives Of ◽  
Fluorescent Derivatives

Abstract A rapid and sensitive liquid chromatographic (LC) method with fluorometric detection was developed to detect sulfadiazine, sulfathiazole, sulfamethazine, sulfamonomethoxine, sulfamethoxazole, and sulfadimethoxine residues in bovine serum and milk. p-Aminobenzoic acid (PABA) was added as an internal standard. The sulfonamides were extracted from samples and derivatized with fluorescamine, and 50 μL was injected into a NovaPak C18 LC column and eluted with acetonitrile– 10 mM potassium phosphate (30 + 70, v/v). The sulfonamides were detected fluorometrically (excitation, 390 nm; emission, 475 nm), and their retention times ranged from 6.2 to 16.5 min without interference from coextractives. The detection limit for standard sulfonamide solution was 0.1 ng/mL; the calibration curves were linear between 1 and 100 ng/mL in the presence of PABA as internal standard. Recovery rates of sulfonamides from spiked samples (1 and 10 ppb) were 95.4–107.2 and 81.4–89.6% for serum and 80.7–91.1 and 62.6–84.1% for milk, respectively.

Reverse Phase Liquid Chromatographic Determination of Vitamins D2 and D3 in Milk

1982 ◽  
Vol 65 (4) ◽  
pp. 791-797
Author(s):  
Juan F Muniz ◽  
C Timothy Wehr ◽  
H Michael Wehr
Keyword(s):  
Vitamin D ◽  
Mobile Phase ◽  
Internal Standard ◽  
Product Type ◽  
Vitamin D2 ◽  
Reverse Phase ◽  
Reverse Phase Column ◽  
Liquid Chromatographic ◽  
Phase Column

Abstract A single column reverse phase high pressure liquid chromatographic method is described for the determination of vitamins D2 and D3 in fluid milk. Resolution of vitamin D2 from D3 is helpful for use as an internal standard. The method involves overnight saponification at room temperature, extraction of unsaponifiables, precipitation of cholesterol, and aluminum oxide column cleanup. Sample extracts were chromatographed under isocratic conditions on a 10 μVydac reverse phase column using acetonitrile- methanol (90 + 10) as the mobile phase. In addition, a MicroPak MCH-5 reverse phase column with acetonitrile as the mobile phase was used with an automatic system for one product type. Thirty samples each of homogenized (3.8% fat), low fat (2.07c fat), and skim (≤0.5% fat) milk spiked with 200,400, and 600 IU vitamin D/qt were analyzed. Coefficient of variation (CV) and percent recovery for each product type and each spike level of vitamins D2 and D3 were calculated from 10 replicate analyses. Vitamin D2 recoveries for all product types at the 3 fortification levels varied from 85.2 to 99.7%; vitamin D3 recoveries varied from 85.9 to 98.8%. The minimum detectable quantity of vitamin D in milk was 15IU/qt.

High Pressure Liquid Chromatographic Determination of Supplemental Methionine in Poultry Premix

1982 ◽  
Vol 65 (1) ◽  
pp. 62-65
Author(s):  
Dubravka Matešič
Keyword(s):  
High Pressure ◽  
Mobile Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Buffer Solution ◽  
Reverse Phase ◽  
High Pressure Liquid Chromatographic ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Supplemental methionine was extracted from a feed sample with O.IM HCI and separated by reverse phase or ion-exchange high pressure liquid chromatography and isocratic elution with KH2PO4 buffer solution as the mobile phase. Methionine was detected at 205 nm. The most reliable results were obtained by using reverse phase chromatography, 0.05M KH2PO4 buffer at pH 2.6 as mobile phase, and tyrosine as internal standard.

scholarly journals Liquid Chromatographic Determination of Nalidixic Acid in Pharmaceutical Preparations

1996 ◽  
Vol 79 (2) ◽  
pp. 431-433 ◽  
Author(s):  
Samuel T Walker
Keyword(s):  
Nalidixic Acid ◽  
Mobile Phase ◽  
Potassium Phosphate ◽  
Internal Standard ◽  
Pharmaceutical Preparations ◽  
Chromatographic Determination ◽  
New Method ◽  
Environmentally Safe ◽  
Liquid Chromatographic

Abstract A simple, rapid, and environmentally safe liquid chromatographic (LC) method was developed for the qualitative and quantitative determination of pharmaceutical preparations of nalidixic acid. The new method was applied to commercial preparations of tablets and a suspension of nalidixic acid and found to be satisfactory for both quantitative and qualitative determinations. Previous LC methods either used chloroform to extract, which we were trying to eliminate, or used a mobile phase of about pH 2.5, which will destroy the column coating. TheLC system for the new method uses sul fanilic acid as internal standard, a μ-Bondapak C18 column, and a mobile phase of methanol, 0.0045M dibasic potassium phosphate, and 0.0072M hexadecyltrimethyiammmonium bromide. The detection wavelength is 254 nm. The sample is dissolved in methanol, and an aliquot is injected through a 20 μL injection loop. Average recoveries ranged from 99.4 to 101.3%.

Liquid Chromatographic Determination of Flucytosine in Capsules

1986 ◽  
Vol 69 (5) ◽  
pp. 825-826
Author(s):  
Donald Shostak ◽  
Clifford Klein
Keyword(s):  
Mobile Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Aminobenzoic Acid ◽  
Reverse Phase ◽  
Acid Sodium Salt ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method has been developed for determination of flucytosine in capsules. Flucytosine and p-aminobenzoic acid, the internal standard, are separated on a C18 reverse phase column using water-methanol-acetic acid mobile phase containing 1-octanesulfonic acid sodium salt. Compounds are detected photometrically at 285 nm. Mean assay results for 250 and 500 mg commercial capsules were 101.5% (n = 5) and 100.2% (n = 5) of declared, respectively. Mean recovery of flucytosine added to commercial capsules was 99.3 %.

Analysis of Pharmaceutical Dosage Forms for Oxfendazole: I. Reverse Phase Liquid Chromatographic Determination of Oxfendazole in Swine Premix

1986 ◽  
Vol 69 (1) ◽  
pp. 20-24
Author(s):  
Jeffrey Fleitman ◽  
Daniel Neu ◽  
Gary Visor
Keyword(s):  
Mobile Phase ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
Organic Content ◽  
Reverse Phase ◽  
Pharmaceutical Dosage Forms ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract A reverse phase liquid chromatographic (LC) procedure is described for quantitating oxfendazole (2-(methoxycarbonylamino)-5-phenyIsuIfinylbenzimidazole)) in swine premix. Sample preparation consists of extracting oxfendazole with an acetone-methanol mixture. An aliquot of the extract is then centrifuged to separate undissolved premix excipients. Internal standard is added to the supernate and the sample is further diluted with water-acetonitrile-phosphoric acid (80 + 20 + 1). Oxfendazole is quantitatively determined using a Partisil-5-ODS-3 column with acetonitrile-O.OlM phosphate buffer (pH 6.0) as the mobile phase. The method is stability specific and yields a mean recovery of 101.1 ± 0.4% for the 1.35% premix formulation. The dependence of chromatographic performance characteristics on mobile phase organic content, pH, and buffer concentration is also reported.

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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