Portable near infrared spectroscopy applied to fuel quality control.

Fuel quality control has gained interest in many countries owing to the potential damage of low-quality fuel to engines, the environment, and economy. Thus, the application of analytical techniques to verify quality control of fuels has become crucial. The portable micro-spectrometer in the near infrared region (microNIR) has gained credibility as a successful analytical technique in several quality control sectors. The possibility of real-time analysis using a nondestructive and reliable method is the main advantage of this methodology. In this work, chemometric models (PLS) were developed using microNIR data to determine the amount of biodiesel in diesel (LODBio = 0.5wt%; LOQBio = 1.8wt%; and RMSEPBio = 1.8wt%); sulfur in diesel (LODS = 2.4mgL-1; LOQS = 8.0mgL-1; and RMSEPS = 13.2mgL-1); gasoline, ethanol, and methanol in C-type gasoline (LODgas = 0.55wt%; LOQgas = 1.84wt%; and RMSEPgas = 0.81wt%; LODeth = 0.75wt%; LOQeth = 2.5wt%; and RMSEPeth = 3.81wt%; and LODmet = 0.85wt%; LOQmet = 2.84wt%; and RMSEPmet = 1.80wt%); and water, methanol, and ethanol in ethanol-hydrated fuel (EHF) (LODH2O = 0.04wt%; LOQH2O = 1.29wt%; and RMSEPH2O = 1.05wt%; LODmet = 0.52wt%; LOQmet = 1.73wt%; and RMSEPmet = 2.78wt%; and LODeth = 1.22wt%; LOQeth = 4.07wt%; and RMSEPeth = 4.41wt%). A total of 181 blends were prepared, with biodiesel and sulfur contents ranging from 0 to 100wt% and 10-500mgL-1, respectively. For gasoline blends, the gasoline, ethanol, and methanol contents ranged from 0.0 to 75.0wt%, 25.0-75.0wt%, and 0.0-50.0wt%, respectively. In the EHF control, the ethanol, water, and methanol contents ranged from 0.0 to 100.0wt%, 0.0-50.0wt%, and 0.0-50.0wt%, respectively. The proposed method presented high precision and accuracy in all cases, and the results showed that the microNIR technique had excellent performance in fuel quality control.

Portable near infrared spectroscopy applied to quality control of Brazilian coffee.

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.

Chemical characterization of synthetic cannabinoids by electrospray ionization FT-ICR mass spectrometry.

The synthetic cannabinoids (SCs) represent the most recent advent of the new psychotropic substances (NPS) and has become popularly known to mitigate the effects of the Δ(9)-THC. The SCs are dissolved in organic solvents and sprayed in a dry herbal blend. However, little information is reported on active ingredients of SCs as well as the excipients or diluents added to the herbal blend. In this work, the direct infusion electrospray ionization Fourier transform ion cyclotron mass spectrometry technique (ESI-FT-ICR MS) was applied to explore the chemical composition of nine samples of herbal extract blends, where a total of 11 SCs (UR-144, JWH-073, XLR-11, JWH-250, JWH-122, AM-2201, AKB48, JWH-210, JWH-081, MAM-2201 and 5F-AKB48) were identified in the positive ionization mode, ESI(+), and other 44 chemical species (saturated and unsaturated fatty acids, sugars, flavonoids, etc.) were detected in the negative ionization mode, ESI(-). Additionally, CID experiments were performed, and fragmentation pathways were proposed to identify the connectivity of SCs. Thus, the direct infusion ESI-FT-ICR MS technique is a powerful tool in forensic chemistry that enables the rapid and unequivocal way for the determination of molecular formula, the degree of unsaturation (DBE-double bond equivalent) and exact mass (<1ppm) of a total of 55 chemical species without the prior separation step.

Chemical profile of mango (Mangifera indica L.) using electrospray ionisation mass spectrometry (ESI-MS).

Mangifera indica L., mango fruit, is consumed as a dietary supplement with purported health benefits; it is widely used in the food industry. Herein, the chemical profile of the Ubá mango at four distinct maturation stages was evaluated during the process of growth and maturity using negative-ion mode electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI(-)FT-ICR MS) and physicochemical characterisation analysis (total titratable acidity (TA), total soluble solids (TSS), TSS/TA ratio, and total polyphenolic content). Primary (organic acids and sugars) and secondary metabolites (polyphenolic compounds) were mostly identified in the third maturation stage, thus indicating the best stage for harvesting and consuming the fruit. In addition, the potential cancer chemoprevention of the secondary metabolites (phenolic extracts obtained from mango samples) was evaluated using the induction of quinone reductase activity, concluding that fruit polyphenols have the potential for cancer chemoprevention.