Factors Affecting the Sensitivity of Hydroxyl Group Content Analysis of Biocrude Products via Phosphitylation and 31P NMR Spectroscopy was written by Kusinski, Matthew;Gieleciak, Rafal;Hounjet, Lindsay J.;Chen, Jinwen. And the article was included in Energy & Fuels in 2021.Safety of Pyridinehydrochloride This article mentions the following:
A useful method for quantifying concentrations of various hydroxyl group containing mol. species in biocrudes involves chem. converting species into nonionizable, P-functionalized derivatives independently observed and quantified by phosphorus-31 NMR (31P NMR) spectroscopy. Full validation of this method requires improved understanding of its applicability to different biocrude matrixes. The limits of detection (LODs) and limits of quantitation (LOQs) for this method are herein determined for concentrations of hydroxyl group containing analytes, grouped by mol. class, within three different biocrude matrixes: a biocrude (BC) product, a fast pyrolysis (FP) product, and an artificial matrix (AM). Matrix water content, known to affect method sensitivity, varies from <1 to 18.31 wt %. Each matrix is used to prepare a series of samples spiked to varying concentrations with three hydroxyl group containing model compounds, which represent (aliphatic) alc., phenolic, and carboxylic acid analyte types. Samples are then phosphitylated with 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane to enable 31P NMR spectroscopic determination of native hydroxyl analyte concentrations LODs and LOQs are determined for each analyte type and for each matrix. Anal. precision is affected by matrix concentrations of interfering analytes and water. Among the matrixes examined, AM, which contains no hydroxyl analytes and has the lowest water content, expectedly exhibits the lowest LODs and LOQs. Matrix LODs range from 0.04 to 0.14 mmol of OH/g, while their LOQs range from 0.10 to 0.41 mmol of OH/g, with both sets of values generally increasing in the order AM < BC < FP. In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7Safety of Pyridinehydrochloride).
Pyridinehydrochloride (cas: 628-13-7) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Reduced pyridines, namely tetrahydropyridines, dihydropyridines and piperidines, are found in numerous natural and synthetic compounds. The synthesis and reactivity of these compounds have often been driven by the fact many of these compounds have interesting and unique pharmacological properties. Safety of Pyridinehydrochloride