Determination of free fatty acids in pharmaceutical lipids by 1H NMR and comparison with the classical acid value

Toward determining fat quality parameters of fish oil by means of 1H NMR spectroscopy

“…1 H NMR spectroscopy was also applied to determine the AV of vegetable oils such as olive and sunflower oil as well as cod liver oil by Skiera et al . These researchers used the signal area of the C 2 methylene group between 2.2 and 2.4 ppm and the integrated singlet of the free carboxyl group between 11 and 12 ppm in order to quantify free fatty acids in mmol/mol triglycerides.…”

Determination of the acid values of edible oils via FTIR spectroscopy based on the OH stretching band

“…To overcome the major disadvantages of this chemical method, such as being time-consuming and labour-intensive, requiring large amounts of organic solvents, and difficulty in distinguishing the end-point with samples containing coloured substances, some improved methods have been developed, including automatic photometric titration (Crispino & Reis, 2013), flow injection analysis Saad, Ling, Jab, & Lim, 2007), and potentiometric titration (Osawa, Goncalves, & Ragazzi, 2006). Various instrumental methods have also been used to determine the AVs of edible oils, including gas chromatography (Tan, Ghazali, Kuntom, Tan, & Ariffin, 2009), high-performance liquid chromatography (Li et al, 2011), capillary electrophoresis (Balesteros et al, 2007), electrochemical impedance spectroscopy (Grossi, Lecce, Toschi, & Ricco, 2014), ultraviolet-visible spectroscopy (Zhang et al, 2015), Raman spectroscopy (Muik & Lendl, 2003), 1 H NMR (Satyarthi, Srinivas, & Ratnasamy, 2009;Skiera, Steliopoulos, Kuballa, Diehl, & Holzgrabe, 2014), infrared spectroscopy, and near-infrared spectroscopy (Adewale, Mba, Dumont, Ngadi, & Cocciardi, 2014;Cantarelli, Funes, Marchevsky, & Camiň a, 2009;Ng, Wehling, & Cuppett, 2007).…”

Quantitative NMR Studies of Multiple Compound Mixtures

“…Recently, pharmaceutical application of qNMR has obtained great attention, which is described by two excellent reviews [186,187] and is also demonstrated by lots of studies reported. In order to secure the drug quality, 1 H qNMR is generally exploited for content determination of APIs, such as diquertin [167], iobitridol [171], and for quantitative analysis of excipients, such as lactose [179], pharmaceutical lipids [180], and 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD) [181]. Liang et al [170] proposed a qNMR method for reliable content determination of clindamycin phosphate (CLP) tablets, which contained about 45% APIs.…”