We developed a high-performance liquid-chromatographic separation of five steroids (estriol, estradiol, cortisol, progesterone, and testosterone), eluting with a water-acetonitrile gradient from a reversed-phase (C18) column. By applying a simplex search algorithm to maximize a chromatographic-response function, we sought to optimize the original conditions of the chromatographic analysis, which did not separate two pairs of overlapping peaks. Our chromatographic-response function incorporated both peak separation and total time of analysis. Three factors were varied simultaneously to maximize this function: flow rate, column temperature, and gradient shape. From the simplex optimization, we selected a flow rate of 1.50 mL/min, a temperature of 52 degrees C, and a linear gradient for our analysis. Subsequent univariate studies of the initial mobile phase composition showed that acetonitrile/water (20/80 by vol) gave an adequate separation.
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High performance liquid chromatography (HPLC) is a key analytical technique that is used in a number of fields. Improving the separation efficiency, stability, and universality of HPLC has been a continuing analytical-chemistry focus. In chromatographic separation, factors such as the composition and ratio of the mobile phase, the type of stationary phase, and the dimensions of the chromatographic column significantly affect the separation efficiency.
View Article and Find Full Text PDFJ Chromatogr Sci
January 2025
Faculty of Pharmacy, Department of Analytical Chemistry, Istanbul Health and Technology University, Istanbul 34469, Turkey.
This study presents a combination of High Performance Liquid Chromatography (HPLC) and ultraviolet (UV) detection that provides the quantification of agnuside in human plasma specimens. Reverse-phase chromatographic separation was carried out with C18 column (150 mm × 4.6 mm × 5 μm), at 25°C with isocratic elution of the mobile phase containing methanol: 0.
View Article and Find Full Text PDFAnal Methods
January 2025
Analytical Chemistry Department, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt.
Hypertension and dyslipidemia are two of the most frequently co-occurring cardiovascular risk factors. The combined regimen of hydrochlorothiazide (HCTZ), rosuvastatin (ROS), and losartan (LOS) helped in the successful management of both conditions. This work's objective is to develop an eco-friendly, sensitive, simple, and reliable chromatographic method for the simultaneous estimation of HCTZ, ROS, and the LOS ternary mixture in their pure form, and pharmaceutical formulations.
View Article and Find Full Text PDFJ Chromatogr Sci
January 2025
Nutrition and Bromatology Group, Department of Analytical Chemistry and Food Science, Faculty of Science, Universidade de Vigo, E-32004 Ourense, Spain.
An efficient reverse-phase high-performance liquid chromatographic method, based on the design of the experiment approach, was developed for the simultaneous determination of capsiate isomers. Critical method parameters, i.e.
View Article and Find Full Text PDFJ Chromatogr Sci
January 2025
Division of Chemical and Material Metrology, Korea Research Institute of Standards and Science, 267, Gajeong-ro, Yuseong-gu, Daejeon, 34113Republic of Korea.
We developed a reversed-phased high-performance liquid chromatographic method combining ultraviolet detection and integrated pulsed amperometric detection for the simultaneous quantification of dopamine, 5-hydroxyindolacetic acid, homovanillic acid, serotonin, 3,4-dihydroxyphenylacetic acid, norepinephrine and epinephrine. All target components were completely separated in a C18 column with isocratic elution of 5% acetonitrile solution containing 8 mM HClO4 and 0.20 mM 1-octanesulfonic acid as an ion pairing reagent.
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