scholarly journals Multiresidue Determination of Eleven Quinolones in Milk by Liquid Chromatography with Fluorescence Detection

2005 ◽  
Vol 88 (6) ◽  
pp. 1688-1694 ◽  
Author(s):  
Guixiang Yang ◽  
Baoyin Lin ◽  
Zhenling Zeng ◽  
Zhangliu Chen ◽  
Xianhui Huang
Keyword(s):  
Fluorescence Detection ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Phase Gradient ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Multiresidue Determination ◽  
Liquid Chromatographic

Abstract A liquid chromatographic method with fluorescence detection was developed for simultaneous determination of norfloxacin, ofloxacin, ciprofloxacin, pefloxacin, lomefloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, and flumequine in milk. The samples were extracted with 10% trichloroacetic acid/acetonitrile (9 + 1, v/v) and cleaned by Strata-X reversed-phase solid-phase extraction cartridges. The 11 quinolones were separated on a reversed-phase C18 column (Hypersil BDS-C18) with mobile phase gradient elution and detected with fluorescence by means of a wavelength program. The recoveries for milk fortified with the 11 quinolones at 3 levels were 69–88%, with acceptable relative standard deviations of <9% (intraday) and <14% (interday). The limits of detection were 23 μg/L for enrofloxacin, and 1–9 μg/L for the other 10 quinolones.

scholarly journals Determination of Benzoylurea Insecticides in Apples and Pears by Solid-Phase Extraction Cleanup and Liquid Chromatography with UV Detection

1999 ◽  
Vol 82 (1) ◽  
pp. 213-216 ◽  
Author(s):  
Nicholas G Tsiropoulos ◽  
Pipina G Aplada-Sarlis ◽  
George E Miliadis
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Phase Extraction ◽  
Relative Standard ◽  
Benzoylurea Insecticides ◽  
Preliminary Extraction ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was developed and statistically validated for simultaneous determination of 5 benzoylurea insecticides (di-flubenzuron, triflumuron, teflubenzuron, flufenoxuron, and lufenuron) in apples and pears. It involves preliminary extraction with ethyl acetate–sodium sulfate and cleanup on silica solid-phase extraction cartridges using dichloromethane–2-propanol (9 + 1) as eluant. The eluate is dried under nitrogen and redissolved in methanol. Benzoylurea insecticides are determined by reversed-phase LC with gradient elution at 42°C and UV diode array detection. Recoveries from samples fortified with the 5 insecticides at 0.02–0.5 mg/kg ranged from 83 to 102% for apples and from 75 to 99% for pears. Relative standard deviations were 0–12%. Limits of detection were 0.01 mg/kg for apples and 0.02 mg/kg for pears.

scholarly journals Application of Liquid Chromatography to the Simultaneous Determination of Acetylsalicylic Acid, Caffeine, Codeine, Paracetamol, Pyridoxine, and Thiamine in Pharmaceutical Preparations

2001 ◽  
Vol 84 (3) ◽  
pp. 676-683 ◽  
Author(s):  
Natividad Ramos-Martos ◽  
Francisco Aguirre-Gómez ◽  
Antonio Molina-Díaz ◽  
Luis F Capitán-Vallvey
Keyword(s):  
Salicylic Acid ◽  
Acetylsalicylic Acid ◽  
Simultaneous Determination ◽  
Pharmaceutical Preparations ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract This paper describes a rapid reversed-phase liquid chromatographic method, with UV detection, for the simultaneous determination of acetylsalicylic acid, caffeine, codeine, paracetamol, pyridoxine, and thiamine in pharmaceutical preparations. A reversed-phase C18 Nucleosil column is used. The mobile phase consists of 2 successive eluants: water (5 min) and acetonitrile–water (75 + 25, v/v; 9 min), both adjusted to pH 2.1 with phosphoric acid. Before determination acetylsalicylic acid is completely converted to salicylic acid by alkaline hydrolysis. Salicylic acid, caffeine, paracetamol, pyridoxine, and thiamine are all detected at 285 nm, whereas codeine is detected at 240 nm. Calibration curves were linear for salicylic acid, caffeine, paracetamol, and pyridoxine in the range of 50–500 mg/L, and for codeine and thiamine in the range of 50–1000 mg/L. The method was applied to the analysis of 13 fortified commercial pharmaceutical preparations. Recoveries ranged from 92.6 to 105.5%, with relative standard deviations of 1.1–5.8%.

scholarly journals Simultaneous Determination of Chlorpheniramine Maleate and Dexamethasone in a Tablet Dosage Form by Liquid Chromatography

2005 ◽  
Vol 88 (6) ◽  
pp. 1677-1683 ◽  
Author(s):  
María A Moyano ◽  
María A Rosasco ◽  
María T Pizzorno ◽  
Adriana I Segall
Keyword(s):  
Potassium Phosphate ◽  
Reversed Phase ◽  
Chlorpheniramine Maleate ◽  
Constant Flow Rate ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Tablet Dosage ◽  
Liquid Chromatographic ◽  
Interday Precision

Abstract An accurate, simple, reproducible, and sensible liquid chromatographic method was developed and validated for the determination of chlorpheniramine maleate and dexamethasone in a tablet formulation. The analysis was performed at room temperature on a reversed-phase C18 column with UV detection at 254 nm. The mobile phase consisted of 7.5 mM monobasic potassium phosphate in methanol–water (62.5 + 37.5) at a constant flow rate of 1 mL/min. The method was validated in terms of linearity, precision, accuracy, and specificity by forced decomposition of chlorpheniramine maleate and dexamethasone initiated by using acid, base, water, hydrogen peroxide, heat, and light. The response was linear in the ranges of 0.04–0.12 and 0.006–0.016 mg/mL for chlorpheniramine maleate (r2 = 0.9999) and dexamethasone (r2 = 0.9994), respectively. The relative standard deviation values for intra- and interday precision studies were 2.39 and 2.02, respectively, for chlorpheniramine maleate and 2.39 and 1.25, respectively, for dexamethasone. Recoveries ranged from 95.07 to 101.95% for chlorpheniramine maleate and from 97.75 to 102.10% for dexamethasone.

scholarly journals Simultaneous Determination of Bioactive Xanthone Glycosides and Norlignans from Ethanolic Extract of Anemarrhena asphodeloides by Liquid Chromatography

2008 ◽  
Vol 91 (6) ◽  
pp. 1271-1277 ◽  
Author(s):  
M Nurul Islam ◽  
Hye Hyun Yoo ◽  
Jun Lee ◽  
Joo Won Nam ◽  
Eun Kyoung Seo ◽  
...  
Keyword(s):  
Ethanolic Extract ◽  
Reversed Phase ◽  
Linear Behavior ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Aggregation Inhibition ◽  
Phase Liquid ◽  
Liquid Chromatographic ◽  
Anemarrhena Asphodeloides

Abstract The rhizomes of Anemarrhena asphodeloides Bunge (Liliaceae) are prescribed as crude drugs in herbal medication for the treatment of various diseases such as diabetes, inflammation, and platelet aggregation inhibition. A simple, sensitive, and precise reversed-phase liquid chromatographic method was developed to study the quantitative determination of 5 bioactive compounds from these rhizomes, namely, neomangiferin, mangiferin, isomangiferin, nyasol, and methylnyasol. Chromatographic analysis was performed on Capcell Pak C18 column (150 4.6 mm, 3 m) with a mobile phase consisting of acetonitrile, methanol, and 0.1 formic acid at a flow rate of 1.00 mL/min. Quantitation was performed using a UV-visible detector at 260 nm. The method for the determination of reported medicinal agents was accurate and reproducible. Excellent linear behavior was observed over the investigated concentration range of 2.5100.0 g/mL for neomangiferin; 1.560.0 g/mL for mangiferin; 0.520.0 g/mL for nyasol; and 0.220.0 g/mL for methylnyasol; correlation coefficient >0.99. The intraday and interday precision over the concentration range of compounds was <6.6 (relative standard deviation) and accuracy was between 94.9 and 109.3. This method can be successfully applied for the analysis of medicinal compounds from the ethanolic extract of A. asphodeloides Bunge.

Comparison of Liquid Chromatographic Method to AOAC Microbiological Method for Determination of L-Tryptophan in Tablets and Capsules

1993 ◽  
Vol 76 (2) ◽  
pp. 414-417 ◽  
Author(s):  
Henry S Kim ◽  
Gerald Angyal
Keyword(s):  
Reversed Phase ◽  
Precolumn Derivatization ◽  
Microbiological Method ◽  
Test Portion ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Phase Liquid ◽  
The Mean ◽  
Liquid Chromatographic

Abstract A reversed-phase liquid chromatographic (LC) method coupled with precolumn derivatization of L-tryptophan with phenylisothiocyanate was compared to the AOAC microbiological method for determining L-tryptophan in tablets and capsules. For the microbiological method, the concentrations of L-tryptophan were 4-8% lower in autoclaved test samples (hot method) than in test samples that were not autoclaved (cold method). When L-tryptophan values obtained by the LC method were compared to those obtained by the cold microbiological method, no significant differences were observed (P > 0.05). The mean relative standard deviations were 2.9% for the LC method and 1.6% for the cold microbiological method. The mean recoveries of standard L-tryptophan added before analysis were 99% for the LC method and 101 % for the cold microbiological method. These results demonstrate that both methods are reliable for determining free L-tryptophan contained in tablets and capsules. However, the LC method has the advantages of using a smaller test portion and having a shorter analysis time.

scholarly journals Determination of Four Fluoroquinolones in Milk by Liquid Chromatography

1997 ◽  
Vol 80 (5) ◽  
pp. 982-987 ◽  
Author(s):  
José E Roybal ◽  
Allen P Pfenning ◽  
Sherri B Turnipseed ◽  
Calvin C Walker ◽  
Jeffrey A Hurlbut
Keyword(s):  
Fluorescence Detection ◽  
Solid Phase ◽  
Raw Milk ◽  
Extraction Column ◽  
Isocratic Elution ◽  
Standard Curve ◽  
Milk Samples ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method with fluorescence detection is presented for the analysis of 4 fluoroquinolones; enrofloxacin (ENRO), ciprofloxacin (CIPRO), sarafloxacin (SARA), and difloxacin (DIFLX) in milk. The procedure consists of extraction of milk with acidified ethanol, isolation and retention on a cation exchange solid-phase extraction column, elution with basic methanol, and LC analysis with fluorescence detection. LC analysis is performed by isocratic elution using an acetonitrile-2% acetic acid (15 + 85) mobile phase and an Inertsil phenyl column with fluorescence detection at excitation and emission wavelengths of 278 and 450 nm, respectively. A target level of 10 ppb for each of the 4 fluoroquinolones has been established for this method. Average recovery from fortified raw milk samples (5-100 ppb each) based on a 5-point standard curve calculation was 70-90%, with relative standard deviations of <15%.

Determination of Total Taurine in Pet Foods by Liquid Chromatography of the Dansyl Derivative: Collaborative Study

2000 ◽  
Vol 83 (4) ◽  
pp. 784-788 ◽  
Author(s):  
Kieran McCarthy ◽  
Claudia Hischenhuber ◽  
Neil Joyce ◽  
G Cherix ◽  
C Hischenhuber ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Collaborative Study ◽  
Gradient Elution ◽  
Taurine Concentration ◽  
Dansyl Derivative ◽  
Relative Standard ◽  
Standard Deviations ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method for the determination of total taurine in pet foods was evaluated in a collaborative study. Ten laboratories assayed 6 blind duplicate pairs of wet and dry pet foods. The taurine in the 6 sample pairs ranged from low (170 mg/kg) to high (2250 mg/kg) concentrations as is. Collaborators also assayed a sample of known taurine concentration for familiarization purposes. Samples were hydrolyzed to release bound taurine, which was subsequently converted to the dansyl derivative and quantitated by gradient-elution LC with fluorescence detection. Repeatability relative standard deviations, RSDr, ranged from 3.2 to 10.0%; reproducibility relative standard deviations, RSDR, ranged from 6.1 to 16.1%. The method has been adopted Official First Action status by AOAC INTERNATIONAL.

Gradient Multipeak Liquid Chromatographic Method for Determination of Ardacin in Bulk Chemical and Premix Formulations

1995 ◽  
Vol 78 (2) ◽  
pp. 289-293
Author(s):  
Hafez Abdel-Kader ◽  
Myriam M Kobylkevich ◽  
Larry S Wigman ◽  
Govind K Menon
Keyword(s):  
Pilot Scale ◽  
Reversed Phase ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
External Standard ◽  
Bulk Chemical ◽  
Method Accuracy ◽  
Liquid Chromatographic ◽  
Reversed Phase Lc

Abstract A liquid chromatographic (LC) method was developed for the determination of ardacin in bulk chemical (78 to 100%, w/w anhydrous) and premix formulations (3.3 to 26.4%, w/w). The method is based on reversed-phase LC resolution of ardacin components and detection by UV absorbance at 220 nm. Ardacin has 10 components, and each component can be quantitated separately. Total ardacin is determined by summing the areas of the 10 component peaks. Calculations are performed using an external standard approach. The method is linear for ardacin at 50 to 150 μ/mL. The method accuracy for a typical bulk chemical is ± 1.5%, w/w (relative standard deviation [RSD], 1.6%), and recovery from a typical pilot scale premix is 99.9% (RSD, 3.4%). The method is useful for monitoring stability during storage.

scholarly journals Simple and Rapid Liquid Chromatography Method for Determination of Rifabutin in Plasma

2013 ◽  
Vol 9 (2) ◽  
pp. 26-29 ◽  
Author(s):  
AK Hemanth Kumar ◽  
V Sudha ◽  
Geetha Ramachandran
Keyword(s):  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Pharmacokinetic Studies ◽  
Chromatography Method ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatography Method ◽  
Liquid Chromatographic

A high performance liquid chromatographic method for determination of rifabutin in human plasma was  developed. The method involved deproteinisation of the sample with acetonitrile and analysis of the  supernatant using a reversed-phase C18 column (250mm) and UV detection at a wavelength of 265nm.  The assay was specific for rifabutin and linear from 0.025 to 10.0μg/ml. The relative standard deviation  of intra- and inter-day assays was lower than 10%. The method was able to remove interfering materials  in plasma, yielding an average recovery of rifabutin from plasma of 101%. Due to its simplicity, the assay  can be used for pharmacokinetic studies of rifabutin. SAARC Journal of Tuberculosis, Lung Diseases & HIV/AIDS; 2012; IX(2) 26-29 DOI: http://dx.doi.org/10.3126/saarctb.v9i2.7975

scholarly journals Determination of Amoxicillin in Trout by Liquid Chromatography with UV Detection after Derivatization

1999 ◽  
Vol 82 (6) ◽  
pp. 1345-1352 ◽  
Author(s):  
Lambert K Sørensen ◽  
Heļga Hansen ◽  
Lena Snor
Keyword(s):  
Solid Phase Extraction ◽  
Muscle Tissue ◽  
Solid Phase ◽  
Reversed Phase ◽  
Uv Detection ◽  
Phase Extraction ◽  
Phase Gradient ◽  
Repeatability Standard Deviation ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method based on solid-phase extraction was developed for determination of amoxicillin in muscle tissue of rainbow trout. The compound was extracted in an aqueous solution by precipitation of organic material with a mixture of sulfuric acid and sodium tungstate. The extract was processed by solid-phase extraction on an end-capped phenyl sorbent, and concentrated on a divinylbenzene-co-ΛN-vinylpyrrolidone polymeric sorbent. The extract was derivatized and analyzed by reversed-phase gradient LC on a C18 column with UV detection at 323 nm. The method detection limit was 2.9 μg/kg. Mean recovery in muscle was 80.5% (range 10-200 μg/kg). The method was applied to fillets from trout offered feed containing amoxicillin in an aquaculture pilot plant. Amoxicillin was detected in muscle tissue shortly after administration but not 3 weeks later. The relative repeatability standard deviation for incurred residues in muscle tissue was 6.4% (range 11-143 μg/kg).

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