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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.
Analysis of Essential Oils
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Adriana Arigò, Mariosimone Zoccali, Danilo Sciarrone, Peter Q. Tranchida, Paola Dugo, Luigi Mondello
At the outlet of the chromatography column, the analytes emerge separated in time. The analytes are then detected and a signal is recorded generating a chromatogram, which is a signal vs. time graphic ideally with peaks presenting a Gaussian distribution-curve shape. The peak area and height are a function of the amount of solute present, and its width is a function of band spreading in the column (Ettre and Hinshaw, 1993), while its retention time can be related to the solute's identity. Hence, the information contained in the chromatogram can be used for qualitative and quantitative analysis.
Plant Species from the Atlantic Forest Biome and Their Bioactive Constituents
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Rebeca Previate Medina, Carolina Rabal Biasetto, Lidiane Gaspareto Felippe, Lilian Cherubin Correia, Marília Valli, Afif Felix Monteiro, Alberto José Cavalheiro, Ângela Regina Araújo, Ian Castro-Gamboa, Maysa Furlan, Vanderlan da Silva Bolzani, Dulce Helena Siqueira Silva
A recent strategy to couple the sample extraction with chromatographic systems is the online extraction (OLE), developed at the NuBBE laboratories. OLE was invented and patented by Ferreira et al. and consists of inserting dry or fresh plant material inside a chamber in a security guard holder. The precolumn is then connected to a liquid chromatographic system with a six-port valve. As the chromatographic analysis starts, the valve is switched so that the mobile phase flows through the precolumn containing the plant material prior to entering into the chromatographic column; therefore, the mobile phase is used both for extraction and separation. The new technique OLE-LC was compared with conventional sample preparations of medicinal plants and similar peak capacity and number of peaks were found for both methods, indicating that OLE-LC is a feasible technique encompassing sample pretreatment integrated with chromatographic analysis (Ferreira et al., 2016). Although this procedure is not automated yet, some papers have been published using OLE-LC with promising results (Russo et al., 2018; Tong et al., 2018a, 2018b).
On the potential of micro-flow LC-MS/MS in proteomics
Published in Expert Review of Proteomics, 2022
Yangyang Bian, Chunli Gao, Bernhard Kuster
The stationary phase, i.e. the chromatographic column, is central to any LC separation. The physical dimensions of the column and material packed into the column determine the type of analyte and the quantities that can be separated (particle material, internal diameter (i.d.)) and the efficiency of the separation (length, particle size, flow rate, temperature etc.). As for other areas of chromatography, the trend toward smaller particle sizes and the concomitant necessity to separate at very high pressure (ultra-high performance liquid chromatography, UHPLC, >1,000 bar) has also been followed in proteomics [8–10]. The use of very small-diameter columns has dominated the field for many years because this offered the sensitivity required to support proteomic applications. As discussed below, this ethos is now beginning to change. For the purpose of the discussion in this review, LC columns are broadly classified into four groups that are based on the internal diameter (Figure 1). Analytical columns typically have 2.1–4.6 mm i.d. and are used at flow rates of >200 μL/min. Columns with 0.5–1 mm i.d. and a flow rate of 10–200 μL/min are referred to as micro-flow, and columns with 150–300 μm i.d. and a flow rate of 1–10 μL/min are known as capillary flow. Finally, columns with an i.d. <100 μm and used at a flow rate <1 μL/min are termed nano-flow [11,12].
In vitro and in vivo evaluation of a sustained-release once-a-day formulation of the novel antihypertensive drug MT-1207
Published in Pharmaceutical Development and Technology, 2021
Napoleon-Nikolaos Vrettos, Peng Wang, Yan Zhou, Clive J. Roberts, Jinyi Xu, Hong Yao, Zheying Zhu
MT-1207 in plasma samples was determined by a validated UPLC-MS/MS method using verapamil hydrochloride as an internal standard. Each time 10 μL of plasma sample were pipetted in 1.5 ml Eppendorf® tube. 200 μL of verapamil hydrochloride 2 ng/mL in acetonitrile were added and vortex was carried out for 5 min. Centrifugation was then carried out at 15000 rpm for 5 min and 100 µL of supernatant were collected for UPLC-MS/MS analysis. The ion source was an electrospray ionisation source (ESI). A positive ion scanning method was used for detection. The solvent gas (nitrogen) flow rate was 1000 L/h, the temperature of the solvent gas was 500 °C, and the capillary voltage was 3.0 kV. The scanning method was Multiple Response Monitoring (MRM). The cone voltage was set at 40 V, while the collision energy was 20 eV. For quantitative analysis, the ion pairs used had m/z 393.26 → 274.04 (MT-1207) and m/z 455.25 → 156.06 (internal standard). The samples were applied to an ACQUITY Ultra Performance Liquid Chromatography system with Xevo TQ-XS Triple Quadrupole Mass Spectrometer with operating software MassLynx V4.2 (Waters Technology Limited Company). The column used was an ACQUITY UPLC BEH C18 liquid chromatography column (2.1 × 50 mm, 1.7 μm). The mobile phase consisted of 0.1% formic acid in water (mobile phase A) and acetonitrile (mobile phase B). Verapamil hydrochloride was used as the internal standard for determination. The gradient elution was: 0–1.2 min: 20–45% B, 1.2–1.5 min: 45–95% B, 1.5–1.8 min: 95% B, 1.8–2.5 min: 95–20% B. The flow rate was set at 0.5 ml/min. The column temperature was set at 45 °C.
In vitro and in vivo analysis of metabolites involved in the TCA cycle and glutamine metabolism associated with cisplatin resistance in human lung cancer
Published in Expert Review of Proteomics, 2021
Jiwei Guo, Jing Yu, Feng Peng, Jinzi Li, Zhirong Tan, Yao Chen, Tai Rao, Yicheng Wang, Jingbo Peng, Honghao Zhou
A new absolute quantitative method was established to detect metabolites with different properties in the TCA cycle and glutamine metabolism in cell extracts, including 2-HG, α-KG, succinate, glutamate, and glutamine. The negative ion mode was selected for analyzing TCA cycle intermediates and the positive ion mode for detecting glutamine metabolism intermediates. For each analyte, we tuned the ESI source temperature, gas 1/2, and DP to obtain the most optimal parent and product ions. Then, CE, DP, and CXP were optimized based on the parent/product ion pair. Optimized MS parameters are presented in Table 1. Then, by changing the type of the chromatographic column, the pH value of the mobile phase, and the selection of gradient elution or isocratic elution, a satisfactory peak shape was obtained. Representative MRM chromatograms of 100 ng/mL standard solutions and A549 and A549-DDP cell extracts are shown in Figure 1.