Application of low field NMR as an alternative technique to quantification of total acid number and sulphur content in petroleum from Brazilian reservoirs

Molecular Properties of Fatty Acid Mixtures Estimated by Online Time-Domain NMR

“…where A 0 is the maximal signal magnitude, R 2 is the spin-spin relaxation rate, and a 0 is the signal baseline, and where A 1 and A 2 are the magnitudes and R 21 and R 22 are the spin-spin relaxation rates of faster and slower decaying components, respectively, and a 0 is the signal baseline. Spin-spin relaxation times, T 2 , T 21, and T 22 , were calculated as inverse values of the corresponding R 2 , R 21, and R 22 as Example fittings by the mono-exponential and bi-exponential functions of the transverse magnetization decay of a hexanoic and oleic acid mixture measured by the automated TD-NMR system are shown in Fig.…”

“…The average RSE for R 2 from the mono-exponential fitting was 1.53%, whereas the average RSEs for R 21 and R 22 from the bi-exponential fitting were 13.65 and 3.32%, respectively ( Table 3). The higher deviations of R 21 and R 22 could have been caused by poor stability of the bi-exponential fitting procedure. Moreover, the (Table 4), mono-exponential fitting provided less deviation in the R 2 and T 2 values as well as in the calculated values of μ NMR , δ NMR , CN NMR, and CL NMR .…”

“…TD-NMR has been proposed as an alternative technique to predict several liquid fuel properties, such as the cetane index, density, flash point, temperature to achieve 50% distillation of a sample (T50) [19], biodiesel content of diesel fuel [14], viscosity, refractive index, American Petroleum Institute (API) gravity [20], total acid number [20,21], and sulphur content [21] in petroleum fractions. The fatty acid composition, viscosity, CN, and iodine content of different intact oilseeds were estimated using 1 H transverse relaxation time T 2 data combined with chemometric techniques [22].…”

Low‐field NMR for quality control on oils

“…Although one‐dimensional (1D) 1 H NMR spectroscopy is used to obtain information about the chemical composition, relaxation measurements provide information about molecular dynamics. The additional use of multivariate data analysis such as principal component analysis (PCA) and partial least squares regression (also named projection on latent structures regression, PLSR) allows the correlation between gravity or viscosity with NMR parameters . Viscosity of heavy crude oils also containing asphaltenes was determined by transverse and longitudinal relaxation …”

A novel, sensitive and non‐destructive method for quantitative determination of lipid in live Eriocheir sinensis using low‐field 1H Nuclear magnetic resonance

“…Low‐field 1 H Nuclear magnetic resonance (LF‐ 1 H NMR) technique is a rapid, non‐destructive, highly reproducible, and sensitive technique (Hazlett et al., 1999; Seton, Hutchison, & Bussell, 1997), and has successfully been applied in quality control of food products such as porcine muscle (Qin, Xu, Zhou, & Wang, 2015; Shao, Deng, Jia, et al., 2016; Shao, Deng, Song, et al., 2016), pork (Shao, Deng, Jia, et al., 2016; Shao, Deng, Song, et al., 2016), salmon (da Silva Carneiro et al., 2016), crude lipid (Barbosa, Sad, Morgan, Figueiras, & Castro, 2016; Jia et al., 2016), egg (Zhao et al., 2016), milk (Salomonsen, Sejersen, Viereck, Ipsen, & Engelsen, 2007), honey (Ribeiro et al., 2014), and cod (Gudjónsdóttir, Arason, & Rustad, 2011). The LF‐ 1 H NMR technique is often employed to investigate the water mobility and/or lipid content of foods because it can measure water or lipid proton relaxation.…”