scholarly journals Determination of Histidine and Related Compounds in Rumen Fluid by Liquid Chromatography

2000 ◽  
Vol 83 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Shaila Wadud ◽  
Ryoji Onodera ◽  
Mamun M Or-Rashid ◽  
Mohammad R Amin
Keyword(s):  
Phosphate Buffer ◽  
Rumen Fluid ◽  
Direct Injection ◽  
Potassium Phosphate ◽  
Potassium Phosphate Buffer ◽  
Absorbance Detection ◽  
Before And After ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract A liquid chromatographic procedure was developed for quantitative determination of histidine (His), histidinol (HDL), histamine (HTM), urocanic acid (URA), imidazolepyruvic acid (ImPA), imidazoleacetic acid (ImAA), and imidazolelactic acid (ImLA) in rumen fluid. The method is based on direct injection analysis by UV absorbance detection at 220 nm. The separation was performed under 2 different chromatographic conditions on a LiChrospher 100 NH2 column. In the first chromatographic system, the mobile phase used for isocratic elution was 67 mM potassium phosphate buffer (monobasic and dibasic) pH 6.45–90% acetonitrile in water (21 + 79); in the second system, an acetonitrile gradient in 63 mM potassium phosphate buffer (monobasic) pH 3.0, obtained by addition of 60 mM phosphoric acid, was used. Analyses of both systems were completed within 32 and 25 min, respectively. The limits of detection of these compounds were (μM): His, 2.8; HDL, 3.7; HTM, 4.0; URA, 0.75; ImPA, 4.7; ImAA, 1.2; and ImLA, 1.3. Recovery of these compounds added to rumen fluid was 97.4–103.0% within a 1-day study and 95.4–99.0% on different day studies. Detectable levels of His were found in the deproteinized rumen fluid of goats, with average concentrations of 16.10, 10.43, 11.14, and 13.62 μM in the rumen fluid collected before the morning feeding and 2, 4, and 6 h after feeding, respectively. HDL, HTM, URA, ImPA, ImAA, and ImLA were not detected in the rumen fluid before and after feeding. Trp, Phe, and Tyr were also identified in the rumen fluid, with average concentrations of 8.25, 29.04, and 12.6 μM, respectively, before the morning feeding.

Simultaneous liquid-chromatographic determination of hypoxanthine, xanthine, urate, and creatinine in cerebrospinal fluid, with direct injection.

1983 ◽  
Vol 29 (8) ◽  
pp. 1543-1546 ◽  
Author(s):  
F Niklasson
Keyword(s):  
Cerebrospinal Fluid ◽  
Direct Injection ◽  
Potassium Phosphate ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Potassium Phosphate Buffer ◽  
Liquid Chromatographic Determination ◽  
Phase Liquid ◽  
Liquid Chromatographic

Abstract In this method for simultaneously determining hypoxanthine, xanthine, urate, and creatinine in cerebrospinal fluid, centrifuged sample is directly injected on a reversed-phase liquid-chromatographic column. On elution with potassium phosphate buffer the compounds are quantified by their absorbance at 260 nm. Random error (CV) was between 1.2 and 3.4% and analytical recoveries were 99-104% at physiological concentrations.

scholarly journals Determination of Disulfiram by Micellar Liquid Chromatography in Illicit Preparations

2011 ◽  
Vol 94 (4) ◽  
pp. 1082-1088 ◽  
Author(s):  
Sandeep-Kumar mourya ◽  
Swati Dubey ◽  
Abhilasha Durgabanshi ◽  
Sudheer Kumar Shukla ◽  
Josep Esteve-Romero ◽  
...  
Keyword(s):  
Direct Injection ◽  
Sodium Dodecyl ◽  
Micellar Liquid Chromatography ◽  
Blood Levels ◽  
Pharmacokinetic Studies ◽  
Optimization Strategy ◽  
Recovering Alcoholics ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract Presently, disulfram is used in aversion therapy for recovering alcoholics. It acts by inhibiting aldehyde dehydrogenase, leading to high blood levels of acetaldehyde. A simple direct injection micellar liquid chromatographic procedure was developed to determine disulfram in illicit preparations (ayurvedic, herbal, divine ash, and traditional medicine), as well as inpharmaceuticals and biological samples (urine). After application of a predictive optimization strategy, the proposed method was developed using a 0.1 M sodium dodecyl sulfate-butanol 4% (v/v) buffered to pH 7 as the mobile phase at a flow rate of 1 mL/min, an octyl silyl (C8) 150 mm column, and diode array detection at 248 nm. Under the above conditions, the analysis time was below 8 min. Validation studies were based on U.S. Food and Drug Administration guidelines. The LOD (3 × SD criterion) was 15 ng/mL and LOQ (10 × SD criterion) was 70 ng/mL for disulfram. The intraday and interday precisions were below 3.5%, recoveries were in the range of 97–102%, and robustness was below 3%. The optimized and validated micellar liquid chromatographic method was successfully applied to the determination of disulfram in ayurvedic, herbal, divine ash, and other samples. The procedure developed could also be used in the felds of QC, routine analysis, and pharmacokinetic studies.

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 Hypoxanthine Content in Fish Tissue

1985 ◽  
Vol 68 (3) ◽  
pp. 444-448 ◽  
Author(s):  
Garth B Burns ◽  
Paul J Ke
Keyword(s):  
Potassium Phosphate ◽  
Adenosine Monophosphate ◽  
Fish Tissue ◽  
Chromatographic Determination ◽  
Fish Tissues ◽  
Absorbance Detection ◽  
Relative Standard ◽  
Operational Errors ◽  
Liquid Chromatographic

Abstract A liquid chromatography (LC) method for determining the hypoxanthine content in fish tissues has been developed. Hypoxanthine is extracted with 0.6M perchloric acid, and determined by LC on a reverse phase microparticulate column with UV absorbance detection. The mobile phase is 0.01M potassium phosphate buffer (pH 4.5). The percent relative standard deviation for measurements by the recommended method was less than 7% with a detection limit of 10 ng. Recoveries of hypoxanthine added to various fish tissues were better than 90%. The operational errors, interferences, and recoveries for spiked samples have been investigated and compare favorably with an established xanthine oxidase enzyme method. The described LC method is simple, rapid, and specific for measuring hypoxanthine content in various fish tissues. Some post-mortem studies have indicated the method may also be used for the determination of adenosine monophosphate, inosine monophosphate, and inosine.

scholarly journals Ultraviolet spectrophotometric method for analytical determination of mianserin hydrochloride in coated tablets and comparison with LC

2015 ◽  
Vol 51 (4) ◽  
pp. 833-837 ◽  
Author(s):  
Letícia Lenz Sfair ◽  
Jeferson Scarpari Graeff ◽  
Martin Steppe ◽  
Elfrides Eva Scherman Schapoval
Keyword(s):  
Low Cost ◽  
Potassium Phosphate ◽  
Analytical Determination ◽  
Potassium Phosphate Buffer ◽  
Precision Data ◽  
Relative Standard ◽  
Significant Difference ◽  
Precision And Accuracy ◽  
Liquid Chromatographic

abstract Ultraviolet spectrophotometric (UV) and Liquid Chromatographic (LC) methods for the determination of mianserin hydrochloride in pharmaceutical formulation were developed and validated. The various parameters, such as specificity, linearity, precision and accuracy were studied according to International Conference on Harmonization (ICH, 2005). For UV method, mianserin hydrochloride was determinate at 278 nm using HCl 0.1 M as the solvent. The response was linear in the concentration range of 20.0 - 140.0 µg/mL (r = 0.9998). Precision data evaluated by relative standard deviation was lower than 2%. The UV method was simple, rapid and low cost. Chromatographic analyses were performed in an Ace C18 column and the mobile phase was composed of methanol, 50 mM monobasic potassium phosphate buffer and 0.3% triethylamine solution adjusted to pH 7.0 with phosphoric acid 10% (85:15). LC method was specific, linear, precise, exact and robust. The results confirmed that the both methods are valid and useful to the routine quality control of mianserin hydrochloride in coated tablets. Statistical analysis by Student´s t-test showed no significant difference between the results obtained by UV and LC methods.

scholarly journals HPLC Determination of Majdine in Vinca herbacea

2011 ◽  
Vol 6 (12) ◽  
pp. 1934578X1100601
Author(s):  
Natia Gagua ◽  
Beatrice Baghdikian ◽  
Fathi Mabrouki ◽  
Riad Elias ◽  
Valentina Vachnadze ◽  
...  
Keyword(s):  
Quality Control ◽  
Chromatographic Separation ◽  
Phosphate Buffer ◽  
Potassium Phosphate ◽  
Solvent System ◽  
Hplc Method ◽  
Potassium Phosphate Buffer ◽  
Good Linear ◽  
Linear Behavior

A reliable HPLC method coupled with DAD detection was developed and validated for determination of majdine in Vinca herbacea. The chromatographic separation was carried out on a Symmetry C18 column (250 mm x 4.6 mm, 5 μm, Waters) with an isocratic solvent system of 25 mM potassium phosphate buffer (pH=3.0)-acetonitrile. UV detection was performed at 225 nm. Good linear behavior over the investigated concentration range was observed with the value of r2 > 0.9978. The method was reproducible with intra- and inter-day variations of less than 4.38%. The proposed method was linear, accurate, precise and specific. The validated method was successfully applied to quantify majdine in various parts of V. herbacea, which was collected during the flowering months of April and May. The results indicated that the developed HPLC method could be used for the quality control of V. herbacea and for the standardization of its extracts in majdine.

Simultaneous determination of neopterin and creatinine in serum with solid-phase extraction and on-line elution liquid chromatography.

1987 ◽  
Vol 33 (11) ◽  
pp. 2028-2033 ◽  
Author(s):  
E R Werner ◽  
D Fuchs ◽  
A Hausen ◽  
G Reibnegger ◽  
H Wachter
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Phosphate Buffer ◽  
Serum Proteins ◽  
Solid Phase ◽  
Potassium Phosphate ◽  
Sample Volume ◽  
Potassium Phosphate Buffer ◽  
Standard Curve

Abstract This is a method for the simultaneous determination of neopterin, a product of interferon-gamma-activated macrophages, and creatinine in serum. Acidified, but not deproteinized serum is applied to a 4-propylbenzene sulfonic acid-modified silica sorbent cartridge, which quantitatively retains the analytes but not the serum proteins. The retained analytes are then eluted from the cartridge directly onto the liquid-chromatography column. Elution from the cartridge is facilitated by a pulse of 0.4 mol/L, pH 6.8 potassium phosphate buffer. On isocratic elution from an octadecylsilica column with potassium phosphate buffer (15 mmol/L, pH 6.0), neopterin is detected by its native fluorescence, creatinine by ultraviolet absorption. Detection limits are 0.5 nmol/L for neopterin, 1 mumol/L for creatinine at a sample volume of 100 microL. The standard curve is linear over the range of concentrations encountered in sera. For both neopterin and creatinine in serum, concentrations so measured agree well with results by established methods.

Liquid Chromatographic Determination of Miconazole Nitrate in Creams and Suppositories

1989 ◽  
Vol 72 (3) ◽  
pp. 442-444
Author(s):  
Theodore A Tyler ◽  
Judith A Genzale
Keyword(s):  
Active Ingredient ◽  
Phosphate Buffer ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Absorbance Detection ◽  
Miconazole Nitrate ◽  
Liquid Chromatographic Determination ◽  
The Mean ◽  
Liquid Chromatographic

Abstract A rapid method has been developed for the determination of miconazole nitrate in creams and suppositories. The sample is dissolved in ethanol, diluted in acetonitrile-water (1 + 1), and injected onto a C18 column. The mobile phase consists of 55% acetonitrile, a triethylammonium phosphate buffer, and an ion-pairing agent. The total run time is less than 4 min, and the active ingredient is determined using absorbance detection at 214 nm. The mean recovery of miconazole from spiked placebo samples was 99.7 ± 0.7% for the cream samples at the 2% level and 98.8 ± 0.3% for the suppository samples at the 4% level.

Liquid Chromatographic Determination of Sodium Saccharin, Caffeine, Aspartame, and Sodium Benzoate in Cola Beverages

1984 ◽  
Vol 67 (4) ◽  
pp. 745-747 ◽  
Author(s):  
Theodore A Tyler
Keyword(s):  
Rapid Method ◽  
Sodium Benzoate ◽  
Phosphate Buffer ◽  
Mobile Phase ◽  
Chromatographic Determination ◽  
Absorbance Detection ◽  
Sodium Saccharin ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A rapid method has been developed for the determination of sodium saccharin, caffeine, aspartame, and sodium benzoate in cola beverages. The sample is degassed, diluted in water, and injected onto a C18 column. The mobile phase consists of 15% acetonitrile in triethylammonium phosphate buffer adjusted to pH 4.3 with NaOH. The total run time is less than 10 min and the active compounds are determined using absorbance detection at 214 nm.

Ultrastructure of Melanin Formation in Curvularia sp., Alternaria sp., and Drechslera Sorokiniana

1977 ◽  
Vol 35 ◽  
pp. 398-399
Author(s):  
M. H. Wheeler ◽  
W. J. Tolmsoff ◽  
A. A. Bell
Keyword(s):  
Potassium Phosphate ◽  
Thielaviopsis Basicola ◽  
Wild Type ◽  
Potassium Phosphate Buffer ◽  
Transmission Microscopy ◽  
Electron Transmission ◽  
Melanin Formation ◽  
Before And After ◽  
Alternaria Sp ◽  
Electron Transmission Microscopy

(+)-Scytalone [3,4-dihydro-3,6,8-trihydroxy-l-(2Hj-naphthalenone] and 1,8-di- hydroxynaphthalene (DHN) have been proposed as intermediates of melanin synthesis in the fungi Verticillium dahliae (1, 2, 3, 4) and Thielaviopsis basicola (4, 5). Scytalone is enzymatically dehydrated by V. dahliae to 1,3,8-trihydroxynaphthalene which is then reduced to (-)-vermelone [(-)-3,4- dihydro-3,8-dihydroxy-1(2H)-naphthalenone]. Vermelone is subsequently dehydrated to DHN which is enzymatically polymerized to melanin.Melanin formation in Curvularia sp., Alternaria sp., and Drechslera soro- kiniana was examined by light and electron-transmission microscopy. Wild-type isolates of each fungus were compared with albino mutants before and after treatment with 1 mM scytalone or 0.1 mM DHN in 50 mM potassium phosphate buffer, pH 7.0. Both chemicals were converted to dark pigments in the walls of hyphae and conidia of the albino mutants. The darkened cells were similar in appearance to corresponding cells of the wild types under the light microscope.

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