Monitoring of Development of Certified Reference Material of Biodiesel by High Field NMR Spectroscopic Techniques

Abstract

Analytical strategies based on Nuclear Magnetic Resonance (NMR) (500 MHz and 800 MHz) spectroscopic techniques ( 1 H, 13 C, 13 C-DEPT) have been presented for monitoring the development of Certified Reference Material (CRM) of biodiesel meeting ASTM D 6751/EN 14214 specifications. The protocol includes the analyses of feedstocks of oil and biodiesel, and impurities generated during transesterification reaction by NMR methods duly validated by standard methods based on GC-MS. The quality parameters such as contents of ester (B100), linolenic acid (C18:3), poly unsaturated fatty acids (PUFA), residual acyl glycerides (mono, di, tri), free glycerin and fatty acid profile, and iodine values have been determined directly by newly developed methods based on NMR techniques in samples of biodiesel produced by transesterification reaction of soybean, sunflower, cotton, canola and corn (maize) oils drawn at different interval of times. The systematic 1H and 13C NMR spectral interpretation has revealed the presence of five types of residual glycerides (AGs) namely 1 or 2 mono glycerides (1-MG, 2-MG); 1,2 and 1,3 di glycerides (1,2-DG; 1,3-DG) and triglycerides (1,2,3-TG) in the biodiesel as well as transesterified products independent of types and nature of vegetable oils. The spectral analyses of samples at 800 MHz NMR instrument has provided enhanced sensitivity and resolution of signals of interest, which enabled identification of very low levels of various AGs. The repeatability standard Deviation (%SD) of quality parameters show that the NMR methods provide results with acceptable precision. The accurate and rapid profiling of residual impurities generated during transesterification reaction without any further chemical treatment will be an effective guide for the catalyst developer for the syntheses of novel catalysts required for quality control of biodiesel. A rapid and convenient approach has been described for the analyses and quantification of bound and free glycerin in the biodiesel and transesterified products, which will enable rapid quality assessment and certification of CRMs.

comparison of oil extraction methods for algae by NMR and Chromatographic techniques

“…The GC-MS analyses of FAMEs of combined Accelerated Solvent CH, DCM and MeOH extracts of three algae biomass samples, CHM, SN and CHL, have been carried out with the objective to find out the nature of the polar components, particularly conjugated/ un conjugated olefinic oxy fatty acid or esters known as oxylipin [51][52][53][54] . The GC-MS results were interesting, particularly the profile of oxo acids and minor hydrocarbon components ( Table 4).…”

“…The oxo acids are generated by enzymatic cleavage of oxidized unsaturated fatty acids such as C18:3, C20:5 and C22:6. These are precursors for the formation of pheromones, the C11 conjugated hydrocarbons [51][52][53][54] .…”

Towards Thermally Reversible Networks Based on Furan-Functionalization of Jatropha Oil

“…The number of double bonds in the jatropha oil was determined by using the signal at δ 5.34 ppm, which is assigned to the vinyl protons [48,49]. The signal at δ 2.01 and 2.75 ppm were also examined, since they represent allylic and bisallylic protons in the C16:1, C18:1, and C18:2 fatty acid chains of the oil [48,49]. The extent of the epoxidation reaction was determined by the area reduction of the relevant peaks.…”

Biodiesel and Polyunsaturated Fatty Acid (PUFA) Potential of MicroalgaeBiomass-A Short Review

“…Chemically, biodiesel is a mixture of fatty acid mono alkyl esters. It is produced by a transesterification reaction between natural occurring triglycerides and alcohol in the presence of a catalyst [17,18]. The fatty acid content and composition comprising of algae lipids are entirely dependent upon the types of species and cultivation conditions, mainly nutrients, employed for their cultivation [1][2][3]5,8].…”

“…The fatty acids profile of algal oil is comprised of C12-C24 saturated and unsaturated fatty acids, which is more or less similar to those present in vegetable and fish oils [8][9][10]. TGs from microalgae biomass are converted into fatty acid methyl ester (FAME) (biodiesel) by usual chemical hydrolysis followed by esterification or enzymatic transesterification [17,18]. Biodiesel from microalgae can be used as B100 (neat biodiesel) or blended with conventional diesel at a level of 5% (B5) or 7% (B10) or 20% (B20) [18][19][20][21].…”