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We propose the use of the low-field 1 H NMR technique to predict various properties of petroleum fractions with °API ranging from 21.7 to 32.7. The experimental data obtained by standard methodologies (ASTM D-1218, D 445-06, D-664-06, D-2892, and D-4052) were correlated with the mean values of the 1 H transverse relaxation time in the range between 25 and 675 ms. Results of the present work showed good correlations between the NMR relaxation data with viscosity, total acid number, refractive index, and API gravity. The main advantage of the proposed method is its nondestructiveness, together with its speed and the fact that it does not require solvents/dilution. This allows the assessment of several properties of petroleum fractions simultaneously, based on the output of only one NMR experiment, leading to large economy in terms of energy, time, and costs.

The use of portable micro-spectrometers such as a micro near infrared region (microNIR) spectrometer is a promising technique for solving analytical problems in several areas of science. This work evaluated the potential of microNIR in quality control of Arabica coffee. Arabica coffee has a high commercial value product, motivating the development of analytical methods with high sensitivity and accuracy for detection of its adulteration. Herein, microNIR was successfully used to determine the quality of Arabica coffee by identification and quantification of adulterations such as Robusta coffee (in different roasting levels), as well as corn, peels, and sticks. MicroNIR was combined with multivariate calibration by partial least squares (PLS) and principal component analysis (PCA). A total of 125 blends were produced, containing thirteen different concentrations of the adulterants (corn and peels/sticks, and the Robusta coffee) ranging from 1 to 100wt%. Developed PCA and PLS models were also applied to monitor the quality of sixteen commercial coffee samples. The results obtained using microNIR proved the ability of the method to be efficient and capable in the prediction of adulterations with minimum quantification levels (LOQs of 5-8wt%), being able to be applied to quality control of commercial coffee samples. Therefore, microNIR can reduce and simplify the time of analysis and sample preparation step, as well as to guarantee the efficiency of real-time data acquisition owing to its portability.

The application of ambient ionization mass spectrometry such as paper spray ionisation (PSI) is a fast, powerful, and simple method to analyze designer drugs directly on the surface of blotters. PSI-MS does not require nebulizing gas and heating temperature as well as complex protocols for sample preparation.Herein, it was possible to identify and elucidate the chemical structure of designer drugs using tandem mass spectrometry experiments from a triangular blotter. Substances such as lysergic acid diethylamide (LSD), and five new designer drugs (2,5-dimethoxy-4-chloroamphetamine (DOC), 2,5-dimethoxy-4bromoamphetamine (DOB), 25C-NBOMe, 25B-NBOMe, and 25I-NBOMe) were characterized by PSI-MS. The PSI(+)-MS and PSI(+)-MS/MS data confirmed the assignments of the designer drugs and fragmentation mechanisms have been proposed. From losses of 17 Da (NH 3 ), which is typical of primary amines, the CID results suggest the presence of isomers in the chemical composition of the NBOMe class. Additionally, the data were compared to those of ultra-high-resolution mass spectroscopy (positive-ion electrospray ionization coupled with Fourier transform ion cyclotron mass spectrometry, ESI(+)FT-ICR MS).

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Detailed measurements of long-range heteronuclear spin-spin coupling constants, especially (2, 3)J(CH) spin-spin couplings for various cyclopentane derivatives, are reported. The measurements are based on a 2D heteronuclear correlation experiment named G-BIRD(R, X)-CPMG-HSQMBC.

A method for maximum and minimum pour point determination in crude oil was applied, and the chemical composition of 80 samples, American Petroleum Institute (API) gravity, total acid number (TAN), density, kinematic viscosity, and sulfur, asphaltene, and wax contents were analyzed in association with chemometric methods. The results of the 80 analyzed samples showed maximum pour point temperatures from 9 to −36 °C and minimum pour point temperatures from 12 to −36 °C. Heavy oils with asphaltenic chemical composition showed more positive values of pour point (5−8 °C) and showed no significant difference between the maximum and minimum pour points considering the repeatability of the method (3 °C for maximum and 6 °C for minimum). However, the oils with chemical composition with higher wax content and higher API gravity showed lower pour point values from −24 to −6 °C (maximum) and from −30 to −18 °C (minimum), respectively. The principal component analysis (PCA) explained 92% of data variability, showing that the differences among the properties of the samples allowed for their separation by groups and some properties are closely correlated to the pour point.

Low-field (1) H NMR was used in this work for the analysis of mixtures involving crude oils and water. CPMG experiments were performed to determine the transverse relaxation time (T2 ) distribution curves, which were computed by the inverse Laplace transform of the echo decay data. The instrument's ability of quantifying water and petroleum in biphasic mixtures following different methodologies was tested. For mixtures between deionized water and petroleum, one achieved excellent results, with root mean squared error of cross-validation (RMSECV) of 0.8% for a regression between the water content (wt %) and the relative area of the water peak in the T2 distribution curve, or a standard deviation of 0.9% for the relationship between the water content and the relative water peak area, corrected by the relative hydrogen index of the crude. In the case of biphasic mixtures of Mn(2+) -doped water and crude oils, the best result of RMSECV = 1.6% was achieved by using the raw magnetization decay data for a partial least squares regression.