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Asparagus Sp.: Phytochemicals and Marketed Herbal Formulations
Published in Amit Baran Sharangi, K. V. Peter, Medicinal Plants, 2023
Vikas Bajpai, Pratibha Singh, Preeti Chandra, Brijesh Kumar
Complete separation of adjoining reference analytes is certainly not required in MS/MS detection. Normally, a suitable chromatographic column, mobile phase, and elution mode are critically important for good separation. To obtain better resolution, various compositions of solvents were tried to get a suitable mobile phase. Acetonitrile possesses stronger elution capability over methanol, which made it more suitable for the final selection in this method. Similarly, as compared to other tested columns, an Acquity UPLC BEH C18 (2.1 × 50 mm, 1.7 µm; Waters, Milford, MA) column was found more suitable for acidic mobile phase with smoother baseline. After testing various concentrations (0.1%, 0.2% and 0.3%) of formic acid, 0.1% formic acid concentration was finally selected. Formic acid was found more effective for ionization of compounds detected in positive and negative ESI mode. A gradient elution with 0.1% formic acid in water and acetonitrile at a flow rate of 0.4 mL/min with a column temperature of 30°C was resulted in separation of the 7 analytes in less than 5.5 min chromatographic run time. Figure 12.2 shows the typical MRM chromatograms of reference analytes under the above optimized conditions.
Honey-Based Polyphenols: Extraction, Quantification, Bioavailability, and Biological Activities
Published in Megh R. Goyal, Arijit Nath, Rasul Hafiz Ansar Suleria, Plant-Based Functional Foods and Phytochemicals, 2021
Csilla Benedek, John-Lewis Zinia Zaukuu, Zsanett Bodor, Zoltan Kovacs
In recent decades, the styrene-di-vinylbenzene polymeric resin known as Amberlite XAD-2 has received popularity as an adsorbent to extract phenolic compounds from honey. Samples are typically dissolved in hydrochloric acid solution (pH = 2), filtered, and subsequently passed through the resin column. Alternatively, the filtrate can be mixed with Amberlite and stirred for a specified time for better absorption prior to transferring the mixture into the column [54]. Elution is performed with aqueous hydrochloric acid (pH = 2) and then continued with water. This allows separation of less polar phenolic fractions (bound on the adsorbent of the column) from the other polar compounds, like sugars. After elution of the target molecules from the column with methanol, the extracts are evaporated under reduced pressure and then re-dissolved in either water or methanol [16].
Thin-Layer Chromatographic Techniques and Systems
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
James A. Chan, Adorjan Aszalos
Quantitation of materials that have been eluted from the stationary phase are of several types: weight determination, spectrophotometry, fluorometry, bioassay, gas chromatography, and high-performance liquid chromatography. The most crucial point of this method is the selective and quantitative elution of the separated materials from the mobile phase. Elution can be done manually or by specially designed instruments. The method of quantitation after elution from the chromatoplate has been used to quantitate tetracyclines, chroamiphenicol, and sulfadimethoxine individually [37] and simultaneously [38].
Chitosan-coated bovine serum albumin nanoparticles for topical tetrandrine delivery in glaucoma: in vitro and in vivo assessment
Published in Drug Delivery, 2022
Salma El-Sayed Radwan, Riham M. El-Moslemany, Radwa A. Mehanna, Eman H. Thabet, Elsayeda-Zeinab A. Abdelfattah, Amal El-Kamel
Tetrandrine was analyzed in aqueous humor samples using an HPLC-MS method. Aqueous humor samples were vortex-mixed with 400 μL acetonitrile for 1 min and centrifuged at 15,000 rpm to separate precipitated proteins. The supernatant was filtered through a 0.22-μm syringe filter prior to analysis. Separation was carried out on a reversed-phase C18 column (ZORBAX Eclipse Plus C18 column, 4.6 × 150 mm, 5 μm). An isocratic eluent consisting of methanol: acetonitrile, 3:2 (mobile phase A) and 0.1% aqueous formic acid (mobile phase B) in a ratio of 50:50 v/v was used. The injection volume was 20 μL and the flow rate was adjusted to 0.4 mL/min. Elution was carried out at room temperature. The LC-MS system used was Shimadzu® UFLC series (Shimadzu Corporation, Kyoto, Japan) (control unit CBM-20A, 2 pumps LC-20AD, thermally controlled autosampler SIL-20AC, degasser DGU-20A, column oven CTO-20AC) coupled with UV detector SPD-20A and MS detector LCMS-2020 with single quadrupole system and two ion sources ESI or APCI. The data was processed using LabSolutions LCMS® Software (release 5.42 SP4 for LCMS-2020). Mass range: m/z 10–2000, sensitivity: ESI Reserpine 1 pg S/N (RMS)>100, APCI Reserpine 1 pg S/N (RMS)>100, Scan rate: up to 15,000 amu/s.
Enhanced anti-cancer effect using MMP-responsive L-asparaginase fused with cell-penetrating 30Kc19 protein
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2022
Jina Ryu, Sung Jae Yang, Boram Son, Haein Lee, Jongmin Lee, Jinmyoung Joo, Hee Ho Park, Tai Hyun Park
The constructed vectors were used to transform E. coli BL21 (Novagen, Madison, WI, USA), and cells were grown in LB-ampicillin medium at 37 °C in 200 rpm shaking incubator. After induction using isopropyl 1-thio-β-d-galactopyranoside (1 mM) with optical density of 600, cells were further incubated at 37 °C for 4 h. Harvested cells were resuspended in binding buffer (20 mM Tris–HCl, 0.5 M NaCl, 20 mM imidazole, pH 8.0), and disrupted by sonication. After centrifugation (12,000 rpm, 30 min), proteins were loaded to a HisTrap HP column (GE healthcare, Uppsala, Sweden), then non-binding proteins were washed using wash buffer (20 mM Tris–HCl, 0.5 M NaCl, 50 mM imidazole, pH 8.0). Finally, target proteins were purified by fast protein liquid chromatography (FPLC, GE healthcare) using elution buffer (20 mM Tris–HCl, 0.5 M NaCl, 350 mM imidazole, pH 8.0). HisTrap Desalting column (GE healthcare) was used for dialysis through 20 mM Tris–HCl buffer (20 mM Tris–HCl, 0.5 M NaCl, pH 8.0). The purified proteins were quantitated using a Micro BCA kit (Thermo Scientific Inc., Rockford, IL, USA) with a standard bovine serum albumin solution, and then stored at −70 °C for further use.
177Lu-doxycycline as potential radiopharmaceutical: electrochemical characterization, radiolabeling, and biodistribution in tumor-bearing mice
Published in International Journal of Radiation Biology, 2021
Zorana Milanović, Drina Janković, Sanja Vranješ-Đurić, Magdalena Radović, Željko Prijović, Gordana Zavišić, Marko Perić, Dalibor Stanković, Marija Mirković
To confirm the efficacy of radiolabeling and to determine the retention time of 177Lu and 177Lu-labeled doxycycline, high-performance liquid chromatography (HPLC) was performed. 177LuCl3 solution (20 µl) was injected (thrice) into the column, and the radioactivity profile was monitored. 177Lu -doxycycline (20 µl) was injected into the column in triplicate. The elution was monitored by observing the radioactivity profile. HPLC analysis was performed on a Hewlett Packard 1050 chromatography system coupled to a Raytest gamma flow detector. A reversed-phase C-18 column (4.6 × 250 mm, 5 µm particle size) was used for separation. The isocratic elution method was applied, using the mixture of acetonitrile and water (60:40, v/v). The temperature of the column was at room temperature (25 ± 1 °C), and the constant flow rate was set at 0.8 ml/min.