Liquid-chromatographic procedure for simultaneous analysis for eight benzodiazepines in serum.

1982 ◽  
Vol 28 (11) ◽  
pp. 2274-2278 ◽  
Author(s):  
G L Lensmeyer ◽  
C Rajani ◽  
M A Evenson
Keyword(s):  
High Performance ◽  
Reversed Phase ◽  
Gradient System ◽  
Active Metabolites ◽  
Reduced Pressure ◽  
Working Standard ◽  
Standard Curve ◽  
Chromatographic Procedure ◽  
Pharmacologically Active ◽  
Liquid Chromatographic

Abstract We describe an efficient extraction and liquid-chromatographic method for separating commonly encountered benzodiazepine drugs and their pharmacologically active metabolites. After a single extraction of the drugs from serum, chlordiazepoxide, demoxepam, N-desmethyl-chloriazepoxide, diazepam, N-desmethyldiazepam, N-desalkylflurazepam, oxazepam, and prazepam can be resolved and quantified by using a C18 reversed-phase "high-performance" column and a ternary-solvent gradient system. Three separate solutions [60 mmol/L ammonium acetate (pH 7.69), 60 mmol/L acetic acid (pH 2.8), and acetonitrile] were incorporated into a gradient mobile phase such that changes in pH and solvent composition occur. Complete chromatographic resolution of the benzodiazepines resulted, permitting quantification of all within 15 min. The standard curve is linear to at least 8 mg/L for each drug, and the detection limit for each was 0.05-0.10 mg/L. The day-to-day precision for both high and low concentrations yielded CVs of 5 to 9%. Extraction of each drug from serum was 95 to 100% complete. Exogenous and endogenous interferences are minimal. Finally, we circumvented the instability problem of benzodiazepine standards in solution by using a simple reduced-pressure drying process that produces a working standard that is stable for at least nine months.

Liquid-chromatographic separation of urinary 5-hydroxy-3-indoleacetic acid, with measurement at 254 nm.

1980 ◽  
Vol 26 (7) ◽  
pp. 910-912
Author(s):  
P S Draganac ◽  
S J Steindel ◽  
W G Trawick
Keyword(s):  
High Performance ◽  
Indoleacetic Acid ◽  
Colorimetric Method ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Acetate Buffer ◽  
Nitrobenzoic Acid ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract A "high-performance" liquid-chromatographic procedure for 5-hydroxy-3-indoleacetic acid is described and compared with a colorimetric method in which 1-nitroso-2-naphthol is used. The analyte and an internal standard, p-nitrobenzoic acid, were extracted into diethyl ether from urine at pH 4.0 (acidified with HCl) to which sodium chloride had been added, and the ether was back-extracted with acetate buffer, pH 9.2. Aliquots of this extract were injected into a reversed-phase liquid-chromatographic column and eluted with pH 3.5 acetate buffer/methanol (95/5 by vol); the effluent was monitored at 254 nm. The precision (CV) of the method was 11.8% at 1.8 mg/L, 5.5% at 92 mg/L. Analytical recovery averaged 84%. The colorimetric method gave higher values for the analyte than did the chromatographic method for all patients' urines.

Analysis of spectinomycin in fermentation broth by reversed-phase chromatography

2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Hong Yan ◽  
Pei Xu ◽  
Hai Huang ◽  
Juan Qiu
Keyword(s):  
High Performance ◽  
Limit Of Detection ◽  
Fermentation Broth ◽  
Correlation Coefficients ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Hplc Method ◽  
Standard Curve ◽  
Relative Standard ◽  
Liquid Chromatographic

AbstractA pre-column derivatized high-performance liquid chromatographic (HPLC) method with ultraviolet-visible detection was developed to measure the concentrations of spectinomycin in fermentation broth. Derivatization reagents, 2,4-dinitrophenylhydrazine in acetonitrile (5 mg mL−1) and trifluoroacetic acid in acetonitrile (0.8 mol L−1), were added to an aliquot of the fermentation broth, and the mixture was incubated for 60 min at 70°C. The resulting derivative was separated from other compounds by isocratic elution in a reversed-phase column Zorbax SB-C18 (250 mm × 4.6 mm, 5 µm). Mobile phase consisted of acetonitrile, tetrahydrofuran, and water (φ r = 40: 35: 25) and the flow rate was 1.0 mL min−1. The detection wavelength was 415 nm. The standard curve for spectinomycin sulfate was linear with correlation coefficients of 0.9997 in the range of 25 µg mL−1 to 600 µg mL−1. The relative standard deviation values ranged from 0.43 % to 2.18 % depending on the concentration of samples. The average recovery was 101.5 %. The limit of detection was 50 ng mL−1.

scholarly journals Determination of diazepam and its metabolites in serum by the use of liquid chromatography: Mass spectrometry method

2007 ◽  
Vol 64 (10) ◽  
pp. 659-662 ◽  
Author(s):  
Snezana Djordjevic ◽  
Vesna Kilibarda
Keyword(s):  
Biological Fluids ◽  
Accurate Method ◽  
Reversed Phase ◽  
Active Metabolites ◽  
Serum Samples ◽  
Standard Curve ◽  
Routine Identification ◽  
Selective Ion Monitoring ◽  
Pharmacologically Active

Background/Aim. Diazepam is a benzodiazepine anxyolitic. Metabolism of diazepam takes place in liver which generates pharmacologically active metabolites N-desmethyldiazepam, temazepam and oxazepam. The aim of this study was to develop and validate the method of liquid chromatographymass spectrometry (LC-MS) for separation and determination of diazepam and its active metabolites in the serum of rats samples after i.p. application of diazepam in a dose of 10 mg/kg. Methods. The serum samples taken from Wistar rats, were used in LC-MS analysis after the application of 10 mg/kg of diazepam i.p. Results. After alkaline extraction from the serum samples with diethylether and separation on a C18 reversed-phase column by using mobile phase methanolglacial acetic acid-water (50:1:49 v/v), diazepam and its metabolites were quantified. Determination was performed in a selective ion monitoring (SIM) mode, thereby the other exogenous and endogenous compounds did not interfere with this assay. Diazepam, N-desmethyldiazepam, oxazepam and temazepam were eluted in 14 minutes. The standard curve was linear in the range from 10-2 000 ng/ml. The limits of detection for diazepam, N-desmethyldiazepam, oxazepam and temazepam were 4.37, 3.13, 4.38 and 7.31 ng/ml, respectively. The limits of quantitation for diazepam, Ndesmethyldiazepam, oxazepam and temazepam were 14.58, 10.41, 14.59 and 24.36 ng/ml, respectively. Conclusion. The described LC-MS is a simple, sensitive, specific and accurate method and could be used for routine identification and quantification of small concentrations of diazepam and its metabolites in biological fluids.

A high-performance liquid-chromatographic method for routine simultaneous determination of nicotine and cotinine in plasma.

1988 ◽  
Vol 34 (4) ◽  
pp. 724-729 ◽  
Author(s):  
M Hariharan ◽  
T VanNoord ◽  
J F Greden
Keyword(s):  
Simultaneous Determination ◽  
Mobile Phase ◽  
High Performance ◽  
Methylene Chloride ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Standard Curve ◽  
Liquid Chromatographic

Abstract We describe a rapid, sensitive method for the routine simultaneous determination of nicotine and cotinine in 1 mL of plasma. Extraction in 10-mL screw-capped Teflon tubes with methylene chloride after deproteinization with trichloroacetic acid eliminated emulsion formation. The extract, after evaporation and reconstitution in 30 microL of mobile phase, is injected into a reversed-phase C-18 ion-pair column of an isocratic high-performance liquid-chromatographic unit. Absorbance is monitored at 256 nm. The mobile phase is a citrate-phosphate (30 mmol each per liter) buffer mixture containing 50 mL of acetonitrile and 1 mmol of sodium heptanesulfonate per liter. 2-Phenylimidazole is the internal standard. The detection limit is 1 microgram/L for nicotine and 3 micrograms/L for cotinine. The standard curve is linear from 0 to 700 micrograms/L for both compounds. The average CV for nicotine in the concentration range 0-100 micrograms/L is 6.5%, and that for cotinine in the concentration range 50-700 micrograms/L is 4%.

Simultaneous determination of lidocaine and its principal metabolites by liquid chromatography on silica gel, with aqueous eluent.

1984 ◽  
Vol 30 (5) ◽  
pp. 637-640 ◽  
Author(s):  
K Kushida ◽  
K Oka ◽  
T Suganuma ◽  
T Ishizaki
Keyword(s):  
Liquid Chromatography ◽  
Simultaneous Determination ◽  
Silica Gel ◽  
High Performance ◽  
Reversed Phase ◽  
Active Metabolites ◽  
Lower Detection ◽  
Pharmacologically Active ◽  
Organic Amines

Abstract We describe the simultaneous determination of lidocaine and its pharmacologically active metabolites, monoethylglycinexylidide and glycinexylidide, in plasma by "high-performance" liquid-chromatography. By use of a bare ( unbonded ) silica gel with aqueous eluents, separations of organic amines such as lidocaine and its metabolites, which are very difficult and have a poor peak symmetry on bonded reversed-phase packings, were easily accomplished with a good peak symmetry. The method is sufficiently precise, sensitive, and specific. Analytical recoveries of all compounds were greater than 90%; CVs for reproducibility were less than 5% for all compounds; the lower detection limits were 0.1 mg/L or less. This method can be used to monitor the concentrations of these compounds in plasma and to prevent the concentration-related side-effect(s).

High-performance liquid-chromatographic determination of free nicotinic acid and its metabolite, nicotinuric acid, in plasma and urine.

1978 ◽  
Vol 24 (10) ◽  
pp. 1740-1743 ◽  
Author(s):  
N Hengen ◽  
V Seiberth ◽  
M Hengen
Keyword(s):  
Nicotinic Acid ◽  
High Performance ◽  
Isonicotinic Acid ◽  
Internal Standard ◽  
Chromatographic Determination ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Related Substances ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract We report a liquid-chromatographic procedure for determining free nicotinic acid and a metabolite, nicotinuric acid, in plasma and urine. Five-tenths milliliter of urine or deproteinized plasma is evaporated and the residue analyzed isocratically by reversed-phase ion-pair chromatography, with measurement of the eluted nicotinic acid and nicotinuric acid at 254 nm. Nicotinic acid, nicotinuric acid, and the internal standard (isonicotinic acid) have retention times of 7.8, 8.4, and 6.8 min, respectively, in plasma, and 12.3, 13.1, and 10.8 min in urine, because of double column length. Day-to-day reproducibilities (CV) for nicotinic acid and nicotinuric acid within 7.5% are attainable for the concentration ranges 0.1--20 mg/liter, equivalent to 0.81--162 micromol of nicotinic acid and 0.55--11 micromol of nicotinuric acid per liter for plasma; in urine for the range 0.5--100 mg/liter, equivalent to 4--810 micromol of nicotinic acid and 2.8--555 micromol of nicotinuric acid per liter. Metabolites of nicotinic acid such as nicotinamide, N-methylnicotinamide, 2-hydroxypyridine-5-carboxylic acid, and other structurally related substances do not interfere.

Reversed Phase High Performance Liquid Chromatography of Essential Oils

1980 ◽  
Vol 35 (9-10) ◽  
pp. 675-681 ◽  
Author(s):  
Dieter Strack ◽  
Peter Proksch ◽  
Paul-Gerhard Gülz
Keyword(s):  
Essential Oils ◽  
Chromatographic Analysis ◽  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Complex Mixtures ◽  
Naturally Occurring ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract A reversed phase high performance liquid chromatographic procedure for the separation of essential oils is described. Applying water-acetonitrile elution systems on octyl and octadecylsilane- bonded silica, complex mixtures of sequiterpenes and oxygenated volatile constituents can be resolved, comparably to the quality of gas chromatographic analysis. Photometrical detection at different wavelengths can be an important parameter in optimizing the separation of essential oil constituents. The application of the described method is demonstrated with naturally occurring mixtures of terpenes from leaves of Cistus ladanifer.

Liquid-chromatographic separation of urinary 5-hydroxy-3-indoleacetic acid, with measurement at 254 nm.

1980 ◽  
Vol 26 (7) ◽  
pp. 910-912 ◽  
Author(s):  
P S Draganac ◽  
S J Steindel ◽  
W G Trawick
Keyword(s):  
High Performance ◽  
Indoleacetic Acid ◽  
Colorimetric Method ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Acetate Buffer ◽  
Nitrobenzoic Acid ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

Abstract A "high-performance" liquid-chromatographic procedure for 5-hydroxy-3-indoleacetic acid is described and compared with a colorimetric method in which 1-nitroso-2-naphthol is used. The analyte and an internal standard, p-nitrobenzoic acid, were extracted into diethyl ether from urine at pH 4.0 (acidified with HCl) to which sodium chloride had been added, and the ether was back-extracted with acetate buffer, pH 9.2. Aliquots of this extract were injected into a reversed-phase liquid-chromatographic column and eluted with pH 3.5 acetate buffer/methanol (95/5 by vol); the effluent was monitored at 254 nm. The precision (CV) of the method was 11.8% at 1.8 mg/L, 5.5% at 92 mg/L. Analytical recovery averaged 84%. The colorimetric method gave higher values for the analyte than did the chromatographic method for all patients' urines.

Determination of urinary glyoxal and methylglyoxal by high-performance liquid chromatography

2004 ◽  
Vol 42 (2) ◽  
Author(s):  
Kazuki Akira ◽  
Yui Matsumoto ◽  
Takao Hashimoto
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Carbonyl Stress ◽  
Age Related ◽  
Highperformance Liquid Chromatography ◽  
Chromatographic Procedure ◽  
Liquid Chromatographic

AbstractCarbonyl stress compounds such as glyoxal and methylglyoxal have been recently attracting much attention because of their possible clinical significance in chronic and age-related diseases. A high-performance liquid chromatographic procedure has been developed for the simultaneous quantitation of glyoxal and methylglyoxal in human urine. The assay is based on the reaction of these compounds with 1,2-diamino-4,5-dimethoxybenzene to form fluorescent adducts, which are separated by reversed-phase highperformance liquid chromatography in a total run time of 45 minutes and quantitated fluorometrically using 2,3-pentanedione as an internal standard. Derivatization is performed for diluted urine (100–120 mOsm/kg H

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