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BioMicrobialdiesel Production using Microbes in General
Published in Ozcan Konur, Biodiesel Fuels Based on Edible and Nonedible Feedstocks, Wastes, and Algae, 2021
K. V. V. Satyannarayana, Randeep Singh, I. Ganesh Moorthy, R. Vinoth Kumar
In general, two types of standard characterization techniques are used for the analysis of biodiesel, namely chromatographic and spectroscopic analysis. Further, the chromatographic technique is of different types, namely liquid chromatography, gas chromatography, gel permeation chromatography, size exclusion chromatography, supercritical fluid chromatography, and thin-layer chromatography. On the other hand, different types of spectroscopic techniques are infra-red, fluorescence, ultra-violet, proton nuclear magnetic resonance, and inductively coupled plasma mass spectrometry. Other methods and techniques include viscometry, refractive index, titration, and enzymatic and wet chemical methods. Out of all the techniques, gas chromatography due to its accuracy is the most preferred method for biodiesel analysis.
Mobile Phase Effects in Reversed-Phase and Hydrophilic Interaction Liquid Chromatography
Published in Nelu Grinberg, Peter W. Carr, Advances in Chromatography Volume 57, 2020
In high-performance liquid chromatography, the stationary phase is usually a bed of fine solid particles with narrow size distribution, densely packed in a metal, glass or plastic tube – a chromatographic column. The particles may be either fully or only partially porous, such as core-shell columns with a layer of the stationary phase chemically bonded to a support material. On the contrary, monolithic columns do not contain particles; instead, a continuous chromatographic bed fills the full inner column volume. The mobile phase (eluent) is a liquid, usually a mixture of two or more solvents (often containing suitable additives) forced through the column by applying elevated pressure in HPLC. The sample compounds move at different velocities along the column, together with – but more slowly than – the mobile phase. The elution process ideally leads to the eventual sample separation. The separated compounds appear at different times at the outlet from the column as the elution waves (peaks) monitored by a detector attached to the outlet of the column. The elution (retention) time, tR, of the peak maximum is a characteristic property of each sample compound, depending on the distribution constant between the stationary and the mobile phases in the chromatographic column. Hence, the tR, or the retention volume VR, is a useful tool for solute identification.
Porous Carbon Nanostructured Sorbents for Biomedical Application
Published in Zulkhair A. Mansurov, Carbon Nanomaterials in Biomedicine and the Environment, 2020
Almagul R. Kerimkulova, Seitkhan Azat, Zulkhair A. Mansurov
Chromatography is able to bind with the sorbent. Various binding forms with the sorbent are used. It can be London dispersion forces (adsorption chromatography), electrostatic forces (ion-exchange chromatography), or molecular size differences (molecular-sieve chromatography). Depending on aggregative state of the eluent, there are distinguished gas and liquid chromatography. Chromatographic separation is carried out in tubes that filled with a sorbent (column chromatography); in capillaries with a length of several tens of meters, which walls are covered with sorbent (capillary chromatography); on plates that covered with adsorption layer (thin-layer chromatography); on paper (paper chromatography) [3–4]. Chromatography is widely used in laboratories and industry in order to control the production and isolation of individual substances.
Polycyclic aromatic hydrocarbons in aquatic animals: a systematic review on analytical advances and challenges
Published in Journal of Environmental Science and Health, Part A, 2022
Ivelise Dimbarre Lao Guimarães, Francielli Casanova Monteiro, Júlia Vianna da Anunciação de Pinho, Paloma de Almeida Rodrigues, Rafaela Gomes Ferrari, Carlos Adam Conte-Junior
Chromatographic methods are used to separate target analytes from co-extracted interferences in samples and can be divided into two main categories: GC and HPLC. GC is the technique of choice for organic compounds, which can be volatilized without being decomposed or chemically rearranged. HPLC is a useful separation technique for semi-volatile and nonvolatile chemicals or for analytes that decompose on heating. Successful liquid chromatography separation requires the analyte(s) of interest to be soluble in the solvent(s) selected as the mobile phase. Chromatographic methods achieve separation by passing a mobile phase through a stationary phase. The mixture constituents are separated by the difference in elution over the stationary phase with different retention times. The compounds that interact strongly with the stationary phase elute slowly (longer retention times), while compounds that remain in the mobile phase elute rapidly (shorter retention times).[13,23,24]
Rapid quantification of degraded products from methyldiethnolamine solution using automated direct sample analysis mass spectrometry and their removal
Published in Chemical Engineering Communications, 2020
Priyabrata Pal, Abdul Fahim Arangadi, Anjali Achazhiyath Edathil, Vinu Pillai, Fawzi Banat
Gas or liquid chromatography using mass spectrometry (GC-MS or LC-MS) is one of the widely used techniques to detect organic degraded products. A number of recent publications describe the application of electrospray (ESI) ionization technique in LC-MS (Lentz and Houk, 2007) and also MALDI time of flight (TOF) detector for quantification purposes (Guo et al., 2002; Kang et al., 2004; Gogichaeva et al., 2007). These methods are time-consuming and need expertise. Even though MALDI TOF has been used extensively over the years for quantification purposes (Bienvenut et al., 2002; Guo et al., 2002; Pitt et al., 2002; Alterman et al., 2004), Direct Sample Analysis Time of Flight (DSA-TOF) has not been extensively explored, because it is a trace analysis instrument and can cause fragmentation of matrix ions (Whitehouse et al., 2016). However, DSA-TOF mass spectrometry is superior to other analytical techniques owing to its fast and reliable output. Its advantages over other analytical techniques are that (1) it does not require any sample preparation, (2) it is a less complicated method of development, and (3) there is no requirement of upfront chromatographic separation. This technique also provides an instant sample introduction, faster analysis time, and gives immediate results. However, in order to get accurate data, it is essential to optimize both the DSA parameter as well as the TOF parameter which may influence the sample.
A regularizing Kohn–Vogelius formulation for the model-free adsorption isotherm estimation problem in chromatography
Published in Applicable Analysis, 2018
G. Lin, Y. Zhang, X. Cheng, M. Gulliksson, P. Forssén, T. Fornstedt
The separation and purification of the components in a mixture are important processes in many industries, including the fine chemical, pharmaceutical, biomedical, and food industries. Chromatography is a common method used in separation processes to isolate one or several components from a mixture [1]. The mechanism of chromatography is based on the fact that different solutes in the sample interact differently with the stationary phase: some are strongly adsorbed whereas others are barely retained. The outcome of a chromatographic separation is strongly dependent on the adsorption isotherms of the solutes, since they dictate the separation factors and saturation capacities, i.e. how much solute can be adsorbed. Therefore, how to determine adsorption isotherms is an issue of significant importance in chromatography.