scholarly journals Determination of (–)-Quinine and (+)-Quinidine by Liquid Chromatography with Diode-Laser Polarimetric Detection

1999 ◽  
Vol 82 (6) ◽  
pp. 1308-1315 ◽  
Author(s):  
Francisco García Sánchez ◽  
Aurora Navas Díaz ◽  
Angeles García Pareja ◽  
Germán Cabrera Montiel
Keyword(s):  
Liquid Chromatography ◽  
Diode Laser ◽  
Mobile Phase ◽  
High Performance ◽  
Dynamic Range ◽  
Reversed Phase ◽  
Rabbit Serum ◽  
In Series ◽  
Phase Column

Abstract High-performance liquid chromatography using a combination of photometric, fluorimetric, and diode-laser polarimetric detectors in series for the determination of (+)-quinidine and (–)-quinine was investigated. An RP-8 reversed-phase column and methanol-water (80 + 20, v/v) with 0.2% triethylamine as mobile phase at a flow rate of 1 mL/min were used. A dynamic range of 0-200 μg for (+)-quinidine and (+)-quinine was established, with detection limits of 17.0 and 16.7 μg, respectively. An application of this method in spiked rabbit serum was developed.

Separation and Determination of Some Aromatic Sulfones by Reversed-Phase High-Performance Liquid Chromatography

1994 ◽  
Vol 59 (3) ◽  
pp. 569-574 ◽  
Author(s):  
Josef Královský ◽  
Marta Kalhousová ◽  
Petr Šlosar
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Uv Spectra ◽  
Optimum Conditions ◽  
Linear Calibration ◽  
Technical Grade

The reversed-phase high-performance liquid chromatography of some selected, industrially important aromatic sulfones has been investigated. The chromatographic behaviour of three groups of aromatic sulfones has been studied. The optimum conditions of separation and UV spectra of the sulfones and some of their hydroxy and benzyloxy derivatives are presented. The dependences of capacity factors vs methanol content in mobile phase are mentioned. The results obtained have been applied to the quantitative analysis of different technical-grade samples and isomer mixtures. For all the separation methods mentioned the concentration ranges of linear calibration curves have been determined.

4-Nitrophenol in 4-nitrophenyl phosphate, a substrate for alkaline phosphatase, as measured by paired-ion high-performance liquid chromatography.

1977 ◽  
Vol 23 (12) ◽  
pp. 2288-2291 ◽  
Author(s):  
P H Culbreth ◽  
I W Duncan ◽  
C A Burtis
Keyword(s):  
Alkaline Phosphatase ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Flow Rate ◽  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Nitrophenyl Phosphate ◽  
Phase Column ◽  
Reversed Phase Column

Abstract We used paired-ion high-performance liquid chromatography to determine the 4-nitrophenol content of 4-nitrophenyl phosphate, a substrate for alkaline phosphatase analysis. This was done on a reversed-phase column with a mobile phase of methanol/water, 45/55 by vol, containing 3 ml of tetrabutylammonium phosphate reagent per 200 ml of solvent. At a flow rate of 1 ml/min, 4-nitrophenol was eluted at 9 min and monitored at 404 nm; 4-nitrophenyl phosphate was eluted at 5 min and could be monitored at 311 nm. Samples of 4-nitrophenyl phosphate obtained from several sources contained 0.3 to 7.8 mole of 4-nitrophenol per mole of 4-nitrophenyl phosphate.

scholarly journals Development and validation of reversed phase high performance liquid chromatography (RP-HPLC) for quantification of captopril in rabbit plasma

2020 ◽  
Author(s):  
Muhammad Fawad Rasool ◽  
Umbreen Fatima Qureshi ◽  
Nazar Muhammad Ranjha ◽  
Imran Imran ◽  
Mouqadus Un Nisa ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
Reversed Phase ◽  
Rabbit Plasma ◽  
Rp Hplc ◽  
Relative Standard

AbstractTh accurate rapid, simple and selective reversed phase high performance liquid chromatography (RP-HPLC) has been established and validated for the determination of captopril (CAP). Chromatographic separation was accomplished using prepacked ODSI C18 column (250 mm × 4.6 mm with 5 μm particle size) in isocratic mode, with mobile phase consisting of water: acetonitrile (60:40 v/v), pH adjusted to 2.5 by using 85% orthophosphoric acid at a flow rate of 1 mL/min and UV detection was performed at 203 nm. RP-HPLC method used for the analysis of CAP in mobile phase and rabbit plasma was established and validated as per ICH-guidelines. It was carried out on a well-defined chromatographic peak of CAP was established with a retention time of 4.9 min and tailing factor of 1.871. The liquid–liquid extraction method was used for extraction of CAP from the plasma. Excellent linearity (R2 = 0.999) was shown over range 3.125–100 µg/mL with mean percentage recoveries ranges from 97 to 100.6%. Parameters of precision and accuracy of the developed method meet the established criteria. Intra and inter-day precision (% relative standard deviation) study was also performed which was less than 2% which indicate good reproducibility of the method. The limit of detection (LOD) and quantification for the CAP in plasma were 3.10 and 9.13 ng/mL respectively. The method was suitably validated and successfully applied to the determination of CAP in rabbit plasma samples.

Quantitation of Transdermal Tadalafil in Human Skin by Reversed-Phase High-Performance Liquid Chromatography

2012 ◽  
Vol 95 (4) ◽  
pp. 1064-1068 ◽  
Author(s):  
Mohammed H Mehanna ◽  
Abdel M Motawaa ◽  
Magda W Samaha
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Human Skin ◽  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Hplc Method ◽  
Drug Deposition ◽  
Transdermal Permeation

Abstract A reliable and sensitive HPLC method was developed for the quantitation of tadalafil transdermal permeation through human skin. An RP column with UV detection at 290 nm was used for chromatographic separation at ambient temperature. The mobile phase was acetonitrile–water containing 20 mM pH 7 phosphate buffer (35/65, v/v) with a flow rate of 1.0 mL/min. The LOQ achieved was 1 ng/mL, and the calibration curve showed good linearity over the concentration range of 5–2000 ng/mL for tadalafil, with a determination coefficient (R2) of 0.998. The RSD values of intraday and interday analyses were all within 7%. Parameters of validation proved the precision of the method; this validated method was applied for the determination of tadalafil in transdermal permeation and drug deposition in human skin studies.

Determination of bethanidine in plasma by liquid-chromatography with a microbore reversed-phase column.

1983 ◽  
Vol 29 (10) ◽  
pp. 1793-1795 ◽  
Author(s):  
J R Shipe ◽  
A F Arlinghaus ◽  
J Savory ◽  
M R Wills ◽  
J P DiMarco
Keyword(s):  
Liquid Chromatography ◽  
Mobile Phase ◽  
Internal Standard ◽  
Reversed Phase ◽  
Ultraviolet Absorbance ◽  
Standard Curve ◽  
Novel Method ◽  
Phase Column ◽  
Reversed Phase Column

Abstract In this novel method for quantifying bethanidine in plasma, after a multi-step extraction of bethanidine and internal standard from 2.0 mL of plasma, the drugs are separated on a "microbore" C18 reversed-phase column and quantified by their ultraviolet absorbance at 210 nm. The isocratic chromatographic separation takes about 15 min with use of an ion-pairing regent in the mobile phase (acetate buffer/acetonitrile, 9/1 by vol) and a flow rate of 0.25 mL/min. Sensitivity is increased relative to conventional columns, and solvent consumption is reduced by 90%. The standard curve is linear to at least 5 mg/L, and the detection limit is 0.02 mg/L. The within-run precision of the method is excellent (CV 4%) at a midrange concentration of 1.25 mg/L.

Determination of erythrocytic polyamines by reversed-phase liquid chromatography

1991 ◽  
Vol 37 (12) ◽  
pp. 2117-2120 ◽  
Author(s):  
Lucile Gerbaut
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Reversed Phase Liquid Chromatography ◽  
Water Gradient ◽  
Phase Liquid ◽  
Dansyl Derivatives

Abstract A simple and rapid semiautomated procedure for determining polyamines in erythrocytes by high-performance liquid chromatography is described. Putrescine, spermidine, and spermine are converted to fluorescent dansyl derivatives, extracted with cyclohexane, and separated in <10 min on a reversed-phase C18 ODS column, with an acetonitrile-water gradient as the mobile phase. The method showed a coefficient of variation of 2.73% for spermidine and 3.27% for spermine. The respective reference values, evaluated in 10 healthy patients, were 7.88 (SD 2.09) and 5.42 (SD 1.55) μmol/L of packed erythrocytes. Only negligible amounts of putrescine were found.

scholarly journals Determination of Norfloxacin and Enrofloxacin by Solid-Phase Microextraction/High-Performance Liquid Chromatography

2008 ◽  
Vol 91 (6) ◽  
pp. 1339-1343 ◽  
Author(s):  
Ashwini Kumar ◽  
Gaurav Dhingra ◽  
Ashok Kumar malik ◽  
Dhananjay K Tewary
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
Solid Phase Microextraction ◽  
High Performance ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Reversed Phase ◽  
Citrate Buffer

Abstract A solid-phase microextraction (SPME) method followed by separation with high-performance liquid chromatography and subsequent UV detection was developed for the determination of norfloxacin and enrofloxacin. The simple and sensitive preconcentration technique uses 280 nm wavelength in mobile phase of citrate buffer (0.01 M), pH 3.8, prepared in water (A) and acetonitrile (B), with composition of the mobile phase A:B, 40:60, at a flow rate of 1.0 mL/min. A C18 reversed-phase analytical column (5 m) was selected as separation medium for the technique. To obtain optimum extraction efficiency, several parameters relating to SPME were investigated. The method was linear over the range of 10100 ng/mL for norfloxacin and enrofloxacin with a correlation coefficient (R2) value of 0.9972 and 0.9980 for norfloxacin and enrofloxacin, respectively. Using the SPME method, the detection limits (signal-to-noise ratio 3) are 0.17 and 0.12 ng/mL for norfloxacin and enrofloxacin, respectively.

Determination of urinary norepinephrine and epinephrine by liquid chromatography with fluorescence detection and pre-column derivatization

1990 ◽  
Vol 36 (5) ◽  
pp. 732-736 ◽  
Author(s):  
P Moleman ◽  
J van Dijk
Keyword(s):  
Liquid Chromatography ◽  
Present Method ◽  
High Performance ◽  
Reversed Phase ◽  
Fluorescence Derivatization ◽  
Specificity And Sensitivity ◽  
Low Concentrations ◽  
High Concentrations ◽  
Phase Column

Abstract We assayed norepinephrine and epinephrine by utilizing solvent extraction, fluorescence derivatization, and "high-performance" liquid chromatography. A 100-microL aliquot of urine was extracted twice according to Smedes et al. (J Chromatogr 1982;231:25-39) and subsequently incubated with 1,2-diphenylethylenediamine. A 100-microL aliquot of the resulting mixture was injected into a reversed-phase column, and norepinephrine and epinephrine were detected fluorometrically. The within-day CV was 3.0-4.0% and the between-day CV 3.4-7.1% for normal and high concentrations of both analytes. At low concentrations (15-40 nmol/L) these CVs were 4.2-6.8% and 6.8-9.2%, respectively. The detection limit of the assay was less than 0.4 nmol/L for each analyte. We discuss the critical steps for extraction, derivatization, and chromatography. The present method combines the qualities of high precision, specificity, and sensitivity.

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