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High-Performance Liquid Chromatography
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Joel J. Kirschbaum, Adorjan Aszalos
Gradient elution was used to assess the composition of crude Vinca rosea plant extracts into an acid-water mixture. An octadecylsilane analytical column and precolumn (10 cm) was used with a mobile phase of 50–85% methanol-water, both containing 0.1% ethanolamine (no gradient time specified), flowing at 2 ml/min into a detector set to 280 nm [123]. Monomeric and dimeric alcohols could be distinguished by the number of theoretical plates N needed for resolution.
Adulteration of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
The analysis of natural products can be demanding especially in the field of EO research since an EO can contain 300 or more components at a concentration ranging from more than 90% to a few ppm or less of the total oil amount. A separation technique of high efficiency is needed and gas liquid chromatography (GLC) or simply GC is one of the most importantly used analytical methods for volatile compounds and is especially suited in EO and fragrance analysis. With the introduction of capillary columns, the separation performance increased dramatically and theoretical plate numbers of more than 1 × 105 are commonplace and provide gas chromatograms of high resolution (HRGC).
Peptide Separation by Reverse-Phase High-Performance Liquid Chromatography
Published in Roger L. Lundblad, Chemical Reagents for Protein Modification, 2020
Column performance for polypeptide separations is not necessarily related to performance for separation of small molecules. In the latter situation the sample is considered to undergo a series of equilibration steps between the mobile and stationary phases as it passes through the column.51 Retention and separation are thus dependent on the column length (number of “theoretical plates” or equilibration steps). With polypeptides this is not the case; 5-cm columns separate as well as 25-cm columns;19,52 only loading capacity is affected. Pearson et al.52 attribute this phenomenon to the operation of an adsorption-desorption mechanism instead of the multi-step partitioning which occurs with smaller molecules.
An HPLC-UV validated bioanalytical method for measurement of in vitro phase 1 kinetics of α-synuclein binding bifunctional compounds
Published in Xenobiotica, 2022
Omozojie P. Aigbogun, Chukwunonso K. Nwabufo, Madeline N. Owens, Kevin J. H. Allen, Jeremy S. Lee, Christopher P. Phenix, Ed S. Krol
At 0.5 μg/mL and 7.5 μg/mL of the bifunctional compounds, the following parameters of the chromatograms were determined as suitability criteria of the chromatographic system: C8-6-I; retention time (tR = 12.08–12.11 min), column efficiency (N > 16 000 theoretical plates), selectivity or separation factor (α = 1.22), and resolution (Rs > 4.7), 19F-C8-6-I; retention time (tR = 12.34–12.35 min), column efficiency (N > 18 000 theoretical plates), selectivity or separation factor (α = 1.19), and resolution (Rs > 4.4), C8-6-N; retention time (tR = 12.36 min), column efficiency (N > 10 000 theoretical plates), selectivity or separation factor (α = 1.59), and resolution (Rs > 7.5), and 19F-C8-6-N; retention time (tR = 13.11–13.12 min), column efficiency (N > 11 000 theoretical plates), selectivity or separation factor (α > 1.47), and resolution (Rs > 7.1). The obtained values of the suitability of the chromatographic system are shown in Table 3. No endogenous substances in MLM were found to co-elute with analytes of interest.
Characterization and ex vivo evaluation of curcumin nanoethosomes for melanoma treatment
Published in Pharmaceutical Development and Technology, 2022
Rajesh Sreedharan Nair, Nashiru Billa, Lim Yang Mooi, Andrew P. Morris
At low, medium, and high curcumin concentrations, the system suitability parameters such as capacity factor, resolution, theoretical plates, peak symmetry, and signal to noise ratio (S/N) were determined. (Table 2). An excellent resolution above 2.0 and a capacity factor of >3.0 were seen for all the peaks corresponding to curcumin which satisfies the criteria for good separation. The theoretical plate number (n) was >13 000 for all the concentrations analysed. As expected, the S/N ratio increased as the concentration of the analyte increased. The tailing factor was found to be between 1.02 and 1.03. The accuracy of analysis decreases with the increase in peak tailing; a tailing factor close to 1.00 is considered optimal; however, a tailing factor of ˂2.0 is acceptable (ICH 2005).
Preparation, characterization and in vitro evaluation of cisplatin-bound triblock polymeric micelle solution for ovarian cancer treatment
Published in Drug Development and Industrial Pharmacy, 2021
Güliz Ak, Irfan Akartas, Buket Özel, Nur Selvi Günel, Hatice Yeşim Karasulu, Barış Gümüştaş, Ercüment Karasulu, Şenay Hamarat Şanlıer
A linear relationship (r2=0.9991) was found when the peak height ratio of CDDP was plotted against the CDDP concentration. The total run time of analysis was 14 min. The blank solution was injected into HPLC and no additional peak was observed under the peak of CDDP, so the peak purity value of CDDP is one. The equation that represents this relationship is y = 900065X–319944. In order to determine the accuracy of the study, the recovery values were found between 93.90 and 110.64%. For the precision, repeatability, and robustness studies, RSD% values were calculated and found to be less than 2%. The tailing factor was found less than 2 and the number of theoretical plates was found more than 2000. The solution was found stable for 4.75 h after performing the solution stability test. The limit of detection (LOD) value was calculated as 0.09 μg/mL, the limit of quantification value was calculated as 0.29 μg/mL. In a study by [25], DDTC concentration was not stated. However, 10 µL DDTC, which was dissolved in 0.1 N NaOH was added to 80 µL of the sample. The retention time of CDDP peak was detected at 5.8 min. In our study, 100 µL DDTC was added to 1 ml of sample and incubated at 37 °C for 15 min. The retention time was detected as 9.27 min. Mobile phase and column may affect the retention time.