Glycerine Analysis
Eric Jungermann, Norman O.V. Sonntag in Glycerine, 2018
Recently, Kiba and co-workers [18] combined an immobilized GDH enzyme reactor with high-performance liquid chromatography (HPLC) equipment to overcome the lack of specificity of the glycerine-GDH reaction. They point out that GDH catalyzes the reduction of NAD+ with materials other than glycerine, such as 1,2,3-propanetriol, 1,2-ethanediol, 1,2-propanediol, and 1,2-butanediol. Since propanediol is used in the pharmaceutical industry as a solvent for drugs, it might constitute an important interference in analysis of blood samples from patients undergoing chemical therapy. Serum samples are separated on a reversed-phase liquid chromatography column using water as the mobile phase. GDH is covalently bonded to alkanolamines on polystyrene beads and packed into a postcolumn reaction tube. The column effluent is then mixed with an NAD+ solution buffered at pH 10 and passed through the GDH column. NADH produced by the glycerine oxidation is monitored with a flowthrough fluorescence detector (348 nm excitation, 465 nm emission).
Analysis of Essential Oils
K. Hüsnü Can Başer, Gerhard Buchbauer in Handbook of Essential Oils, 2020
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.
Methods in molecular exercise physiology
Adam P. Sharples, James P. Morton, Henning Wackerhage in Molecular Exercise Physiology, 2022
Mass spectrometers that are used for proteomics consist of a ‘source’ that generates charged peptide ions and a system of filters that are used to transfer the ionised peptides into a mass analyser. Electrospray ionisation (ESI) is the most commonly used ionisation source and also provides an interface between liquid chromatography and mass spectrometry. As peptides elute from the liquid chromatography column, they are sprayed through a fine needle near the entrance of the mass spectrometer. The liquid from the chromatography system is evaporated and the peptides enter the ‘gas phase’ and become protonated (i.e. ‘charged’). Positively charged peptides are drawn into the mass spectrometer and are then directed by ion filters that can either permit or exclude different peptides from travelling to the mass analyser. There are several different configurations of mass analysers used in proteomic studies, but they all rely on a general process known as tandem mass spectrometry, which simply means 2 levels of mass analysis are performed. The first level, ‘MS’ or ‘MS1’, measures the mass of intact peptides and the second level, ‘MS/MS’ or ‘MS2’, measures the mass of the fragment ions that are produced when the peptides are broken into smaller pieces through a process known as collision-induced dissociation (CID). The key performance parameters of mass spectrometers are speed, resolution and mass accuracy. Most instruments continuously run through alternating cycles of MS1 and MS2 data collection, and each cycle needs to be completed in less than 1 second to achieve good quality proteomics data. Numerous different peptides are delivered to the mass spectrometer at any particular moment, so the mass analyser must have sufficient power to resolve (i.e. distinguish between) ions of very similar masses. Good mass accuracy is also essential for the unambiguous identification of peptides and post-translationally modified residues, and modern-day instruments routinely achieve a level of mass accuracy of close to 1 parts per million (ppm). It is also important to appreciate that the key performance parameters of mass spectrometers are interrelated. For example, most mass spectrometers achieve better levels of mass resolution at slower rates of data acquisition. Therefore, it is important to optimise instrument settings to suit the aims of different types of experiments.
A review on human body fluids for the diagnosis of viral infections: scope for rapid detection of COVID-19
Published in Expert Review of Molecular Diagnostics, 2021
Sphurti S Adigal, Nidheesh V Rayaroth, Reena V John, Keerthilatha M Pai, Sulatha Bhandari, Aswini Kumar Mohapatra, Jijo Lukose, Ajeetkumar Patil, Aseefhali Bankapur, Santhosh Chidangil
Several studies have reported the use of different spectroscopic techniques for early diagnosis of various diseases using different body fluids as clinical specimen [91]. High-performance liquid chromatography (HPLC) is considered as a versatile tool for separation and analysis of the biological and pharmaceutical compounds. Chromatography column is the heart of chromatography technique and hence a column selection is important to separate the mixture of components in a sample of interest [92]. Generally, chromatography-based techniques are used as standard techniques by industrial sectors, federal agencies, academies, and food and drug administration (FDA). Using chromatography-based-techniques the limit of detection (LOD) for melamine was achieved to the ppb level [93]. The combination of ultrasensitive optical technique Laser-Induced Fluorescence (LIF), with highly efficient separation technique such as HPLC, detection of ultra-trace quantities of individual biomolecules in complex, multicomponent physiological systems is feasible [94]. Our earlier studies demonstrated the capability of HPLC-LIF for protein profile analysis of micro-quantities of clinical samples such as saliva [95], serum [96], cellular samples [16] and tissue homogenates [97] for the diagnosis of cancers of different types.
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.
The management of anti-infective agents in intensive care units: the potential role of a ‘fast’ pharmacology
Published in Expert Review of Clinical Pharmacology, 2020
Dario Cattaneo, Alberto Corona, Francesco Giuseppe De Rosa, Cristina Gervasoni, Danijela Kocic, Deborah Je Marriott
A new liquid-chromatography column technology offers a novel approach to fast chromatography using ‘Active Flow Technology.’ This unique design offers up to 5-times higher flow rates through the column, with the ability to perform a radial split of the flow at the column outlet, and thus still having the appropriate flow rate being delivered to the MS without compromising the ion source, with the remaining flow diverted to waste. The Active Flow Technology column is designed for ultra-high-throughput assays, enabling reductions of up to 80% in run-time and the ability to overcome well-known challenges and limitations of the interface between LC and MS detector. This technology has been developed by Thermo Scientific in partnership with Western Sydney University, Australia, and is in the process of being commercialized.
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