scholarly journals High-performance liquid chromatography of uroporphyrinogen and coproporphyrinogen isomers with amperometric detection

1986 ◽  
Vol 234 (3) ◽  
pp. 629-633 ◽  
Author(s):  
C K Lim ◽  
F Li ◽  
T J Peters
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Ammonium Acetate ◽  
Amperometric Detection ◽  
Reversed Phase ◽  
Fluorescent Detection ◽  
Organic Modifiers ◽  
Ammonium Acetate Buffer ◽  
Effects Of Ph ◽  
Ph Buffer

A reversed-phase h.p.l.c. system, with an ODS-Hypersil column with acetonitrile or methanol in ammonium acetate buffer as mobile phase, is described for the separation of uro-and copro-porphyrinogen isomers. The porphyrinogens are detected amperometrically with sensitivity comparable with that of the fluorescent detection of porphyrins. The effects of pH, buffer concentration and organic modifiers on retention and resolution were studied. The method is suitable for both analytical and preparative separation of porphyrinogens.

scholarly journals Enantioselective HPLC Analysis to Assist the Chemical Exploration of Chiral Imidazolines

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 640 ◽  
Author(s):  
Bruno Cerra ◽  
Antonio Macchiarulo ◽  
Andrea Carotti ◽  
Emidio Camaioni ◽  
Ina Varfaj ◽  
...  
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Hplc Analysis ◽  
Water Solubility ◽  
Pearson Correlation ◽  
Retention Factor ◽  
Reversed Phase ◽  
Base Line ◽  
Structure Property ◽  
Organic Modifiers

In the present work, we illustrate the ability of high-performance liquid chromatography (HPLC) analysis to assist the synthesis of chiral imidazolines within our medicinal chemistry programs. In particular, a Chiralpak® IB® column containing cellulose tris(3,5-dimethylphenylcarbamate) immobilized onto a 5 μm silica gel was used for the enantioselective HPLC analysis of chiral imidazolines synthesized in the frame of hit-to-lead explorations and designed for exploring the effect of diverse amide substitutions. Very profitably, reversed-phase (RP) conditions succeeded in resolving the enantiomers in nine out of the 10 investigated enantiomeric pairs, with α values always higher than 1.10 and RS values up to 2.31. All compounds were analysed with 50% (v) water while varying the content of the two organic modifiers acetonitrile and methanol. All the employed eluent systems were buffered with 40 mM ammonium acetate while the apparent pH was fixed at 7.5. Based on the experimental results, the prominent role of π-π stacking interactions between the substituted electron-rich phenyl groups outside of the polymeric selector and the complementary aromatic region in defining analyte retention and stereodiscrimination was identified. The importance of compound polarity in explaining the retention behaviour with the employed RP system was readily evident when a quantitative structure-property relationship study was performed on the retention factor values (k) of the 10 compounds, as computed with a 30% (v) methanol containing mobile phase. Indeed, good Pearson correlation coefficients of retention factors (r - log k1st = −0.93; r - log k2nd = −0.94) were obtained with a water solubility descriptor (Ali-logS). Interestingly, a n-hexane/chloroform/ethanol (88:10:2, v/v/v)-based non-standard mobile phase allowed the almost base-line enantioseparation (α = 1.06; RS = 1.26) of the unique compound undiscriminated under RP conditions.

scholarly journals Phenobarbital Analysis in Biological Matrix (Blood) by High Performance Liquid Chromatography (HPLC)

2013 ◽  
Vol 20 ◽  
pp. 31-40
Author(s):  
Ouakouak Hamza ◽  
Ben Mohamed Moktar ◽  
Ben Chohra Mostafa ◽  
Abdelhamid Zeghdaoui
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Ammonium Acetate ◽  
Analytical Techniques ◽  
Hplc Method ◽  
Diode Array ◽  
Blood Components ◽  
Ammonium Acetate Buffer

In this work, we have tried to contribute to the analysis of phenobarbital in the blood. To do this, we used different analytical techniques such as liquid chromatography (HPLC). The results obtained in the course of our work, we can conclude that: The HPLC method was separate phenobarbital endogenous blood components, and optimizing the conditions of chromatographic separation as the composition of the mobile phase consisting of 20% acetonitrile + 20% methanol + 60% ammonium acetate buffer. The extraction with diethyl ether to pH = 4; The chromatographic column, microbondapack ZORBAX C18. A system of diode-array UV detection at 254 nm.

TLC-Densitometric and RP-HPLC Methods for Simultaneous Determination of Dexamethasone and Chlorpheniramine Maleate in the Presence of Methylparaben and Propylparaben

2017 ◽  
Vol 100 (1) ◽  
pp. 51-58
Author(s):  
Nehal F Farid ◽  
Ibrahim A Naguib ◽  
Radwa S Moatamed ◽  
Mohamed R El Ghobashy
Keyword(s):  
Particle Size ◽  
Quantitative Determination ◽  
Mobile Phase ◽  
Ammonium Acetate ◽  
Reversed Phase ◽  
Reversed Phase Hplc ◽  
Chlorpheniramine Maleate ◽  
Ammonium Acetate Buffer ◽  
Rp Hplc

Abstract Validated simple, sensitive, and highly selective methods are applied for the quantitative determination ofdexamethasone and chlorpheniramine maleate in the presence of their reported preservatives (methylparaben and propylparaben), whether in pure forms or in pharmaceutical formulation. TLC is the first method, in which dexamethasone, chlorpheniramine maleate, methylparaben, and propylparaben are separated on silica gel TLC F254 plates using hexane–acetone–ammonia (5.5 + 4.5 + 0.5, v/v/v) as the developing phase. Separated bands are scanned at 254 nm over a concentration range of 0.1–1.7 and 0.4–2.8 μg/band, with mean ± SD recoveries of 99.12 ± 0.964 and 100.14 ± 0.962%, for dexamethasone and chlorpheniramine maleate, respectively. Reversed-phase HPLC is the second method, in which a mixture of dexamethasone and chlorpheniramine maleate, methylparaben, and propylparaben is separated on a reversed-phase silica C18 (5 μm particle size, 250 mm, 4.6 mm id) column using 0.1 M ammonium acetate buffer–acetonitrile (60 + 40, v/v, pH 3) as the mobile phase. The drugs were detected at 220 nm over a concentration range of 5–50 μg/mL, 2–90 μg/mL, 4–100 μg/mL, and 7–50μg/mL, with mean ± SD recoveries of 100.85 ± 0.905, 99.67 ± 1.281, 100.20 ± 0.906, and 99.81 ± 0.954%, for dexamethasone, chlorpheniramine maleate, methylparaben paraben, and propylparaben, respectively. The advantages of the suggested methods over previously reported methods are the ability to detect lower concentrations of the main drugs and to show better resolution of interfering preservatives; hence, these methods could be more reliable for routine QC analyses.

High Performance Liquid Chromatography Using Ultrasonic Extraction for Benzoic Acid Analysis in Curry Paste Samples

2019 ◽  
Vol 886 ◽  
pp. 40-45
Author(s):  
Nararat Thongsrinoon ◽  
Netnapha Phiwdee ◽  
Yanada Duangsa ◽  
Khaengkhae Muensub ◽  
Vichayaporn Duang-Iad
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Benzoic Acid ◽  
Mobile Phase ◽  
High Performance ◽  
Ammonium Acetate ◽  
Ultrasonic Extraction ◽  
Optimum Conditions ◽  
Ammonium Acetate Buffer ◽  
Uv Visible

Benzoic acid analysis in curry paste samples were carried out by using high performance liquid chromatography using ultrasonic extraction. Methanol-0.05 M ammonium acetate buffer pH 4.40 in the ratio of 55:45 (%v/v) at a flow rate of 1.00 mL/min was used as the mobile phase and benzoic acid detection was performed at 226 nm using an UV-Visible detector. Under the optimum conditions, linearity of spiked samples ranged from 50 to 3,000 mg/kg. Matrix matched calibrations had determined that benzoic acid contents in southern sour, red, and green curry paste samples were 67.59, 78.62 and 72.33 mg/kg, respectively. Recoveries were obtained from 89.34 to 101.70%, 83.37 to 130.30% and 92.75 to 113.56% with R.S.D. ranged from 2.71 to 6.53%, 4.02 to 11.58% and 5.81 to 6.35%, for southern sour, red, and green curry paste samples, respectively.

scholarly journals High-performance liquid chromatography of type-III heptocarboxylic porphyrinogen isomers

1987 ◽  
Vol 247 (1) ◽  
pp. 229-232 ◽  
Author(s):  
C K Lim ◽  
F Li ◽  
T J Peters
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Mobile Phase ◽  
High Performance ◽  
Ammonium Acetate ◽  
Reversed Phase ◽  
Buffer Concentration ◽  
Organic Modifier ◽  
Type Iii ◽  
Optimum Separation

A reversed-phase h.p.l.c. system is described for the separation of the four type-III heptacarboxylic porphyrinogen isomers. The effects of buffer concentration, pH and type and proportion of organic modifier in the mobile phase on retention and resolution of isomers were studied. Optimum separation on an ODS-Hypersil column was by elution with a ternary mobile phase of acetonitrile, methanol and 1 M-ammonium acetate, pH 5.16 (7:3:90, by vol.). Isomer identification was based on a comparison of their retention times with those of authentic standards, and was further confirmed by h.p.l.c. analysis of the characteristic mixture of three pentacarboxylic porphyrins formed after partial decarboxylation of individual isomers in 0.3 M-HCl at 160 degrees C.

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 Simultaneous Determination of Preservatives (Methyl Paraben and Propyl Paraben) in Sucralfate Suspension Using High Performance Liquid Chromatography

2011 ◽  
Vol 8 (1) ◽  
pp. 340-346 ◽  
Author(s):  
Rajesh M. Kashid ◽  
Santosh G. Singh ◽  
Shrawan Singh
Keyword(s):  
High Performance Liquid Chromatography ◽  
Simultaneous Determination ◽  
Mobile Phase ◽  
High Performance ◽  
Reversed Phase ◽  
Hplc Method ◽  
Reversed Phase Hplc ◽  
Methyl Paraben ◽  
Propyl Paraben

A reversed phase HPLC method that allows the separation and simultaneous determination of the preservatives methyl paraben (M.P.) and propyl paraben (P.P.) is described. The separations were effected by using an initial mobile phase of water: acetonitrile (50:50) on Inertsil C18 to elute P.P. and M.P. The detector wavelength was set at 205 nm. Under these conditions, separation of the two components was achieved in less than 10 min. Analytical characteristics of the separation such as precision, specificity, linear range and reproducibility were evaluated. The developed method was applied for the determination of preservative M.P. and P.P. at concentration of 0.01 mg/mL and 0.1 mg/mL respectively. The method was successfully used for determining both compounds in sucralfate suspension.

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