Chemical QR Code: A simple and disposable paper-based optoelectronic nose for the identification of olive oil odor.

Olive oil is an appreciated food product with high nutritional value, besides being an essential component in many culture diets. In this study, we present for the first time the application of a simple and non-invasive paper-based optoelectronic nose designed in a QR code configuration to evaluate the odor of olive oils. The chemical QR code was fabricated by the addition of 12 dyes, which provided high dimensional data resulting from the interaction between the volatile compounds and the colorimetric array. The color changes were employed to build differential maps with a unique fingerprint (i) to discriminate between olive oil and other edible oil samples; (ii) to quantify nonanaldehyde as an oxidation marker; and (iii) to identify oxidized oils through principal component analysis (PCA) and hierarchical component analysis (HCA). By developing suitable mobile apps, we anticipate the employment of the chemical QR code for portable, low-cost, and in-situ evaluation of food product quality.

Poultry slaughterhouse anaerobic ponds as a source of inoculum for biohydrogen production.

Several waste sources have been studied as substrate sources for the production of biogas rich in hydrogen and for the isolation of bacteria capable of fermenting several substrates for the same purpose. Nonetheless, to simplify the process and minimize production costs, it is important to seek alternatives both for the use of microbial consortia using crude waste and for the use of substrates also in their crude form, without the need for purification. The aim of this study was to use only waste as inoculum and substrate for the biological production of hydrogen. Thus, samples from anaerobic ponds of a poultry slaughterhouse were used as inoculum. Sucrose, pure glycerol (in initial tests) and crude glycerol (inserted in blends with pure glycerol) were used as substrates. H2 production experiments were conducted in batches, using a reactor kept in an anaerobic environment for 11 days, at 35°C, under orbital agitation at 150 rpm. To analyse the composition of the biogas and the presence of soluble metabolic products (SMPs), samples of the headspace gases generated and of the reaction medium were collected. The results using sucrose as substrate indicated that the inoculum under study has potential for bio-H2 production, as it produced CH4-free biogas containing 50-60% H2. The inoculum was also shown to be adaptable to the use of glycerine as a substrate, producing biogas with similar characteristics to those obtained from sucrose degradation; however, it required a longer acclimatization period, and thus more in-depth study is required.

An analytical GC-MS method to quantify methyl dihydrojasmonate in biocompatible oil-in-water microemulsions: physicochemical characterization and in vitro release studies.

Microemulsions (MEs) loaded with methyl dihydrojasmonate (MJ) were developed to improve the aqueous solubility of this drug. The composition of the formulations ranged according to the oil/surfactant ratio (O/S). The MEs were characterized according to diameter of droplets, X-ray diffraction and polarized light microscopy. The MJ identification and quantification was performed by gas chromatography-mass spectrometry (GC-MS). The MJ showed a retention time of ∼16.7 min for all samples. The obtained correlation coefficient from the calibration graph was 0.991. The developed analytical method was effective enough to quantify low and high concentrations of MJ. The increase of the O/S ME ratio led to a reduction of the droplet diameter. All formulations showed an amorphous structure and the behavior varied between isotropic and anisotropic systems. A decrease in the release of MJ with the increase of the O/S ratio in the formulations was observed. The analytical method developed for the quantitative determination of MJ is suitable to detect and quantify the drug compound from different compositions of MEs in the in vitro release test, and by analogy in other prolonged effects related to the drug reservoir effect of these systems was observed, revealing that ME can be a promising nanocarrier for MJ delivery to tumor cells.

Ultrafast gas chromatography method with direct injection for the quantitative determination of benzene, toluene, ethylbenzene, and xylenes in commercial gasoline.

Benzene, toluene, ethylbenzene, and xylenes are some of the most hazardous constituents found in commercial gasoline samples; therefore, these components must be monitored to avoid toxicological problems. We propose a new routine method of ultrafast gas chromatography coupled to flame ionization detection for the direct determination of benzene, toluene, ethylbenzene, and xylenes in commercial gasoline. This method is based on external standard calibration to quantify each compound, including the validation step of the study of linearity, detection and quantification limits, precision, and accuracy. The time of analysis was less than 3.2 min, with quantitative statements regarding the separation and quantification of all compounds in commercial gasoline samples. Ultrafast gas chromatography is a promising alternative method to official analytical techniques. Government laboratories could consider using this method for quality control.

Development and validation of an environmentally friendly attenuated total reflectance in the mid-infrared region method for the determination of ethanol content in used engine lubrication oil.

Lubricating oils are crucial in the operation of automotive engines because they both reduce friction between moving parts and protect against corrosion. However, the performance of lubricant oil may be affected by contaminants, such as gasoline, diesel, ethanol, water and ethylene glycol. Although there are many standard methods and studies related to the quantification of contaminants in lubricant oil, such as gasoline and diesel oil, to the best of our knowledge, no methods have been reported for the quantification of ethanol in used Otto cycle engine lubrication oils. Therefore, this work aimed at the development and validation of a routine method based on partial least-squares multivariate analysis combined with attenuated total reflectance in the mid-infrared region to quantify ethanol content in used lubrication oil. The method was validated based on its figures of merit (using the net analyte signal) as follows: limit of detection (0.049%), limit of quantification (0.16%), accuracy (root mean square error of prediction=0.089% w/w), repeatability (0.05% w/w), fit (R(2)=0.9997), mean selectivity (0.047), sensitivity (0.011), inverse analytical sensitivity (0.016% w/w(-1)) and signal-to-noise ratio (max: 812.4 and min: 200.9). The results show that the proposed method can be routinely implemented for the quality control of lubricant oils.

An environmentally friendly reflectometric method for bumetanide determination in pharmaceuticals.

This paper describes a green analytical procedure for the determination of bumetanide using diffuse reflectance spectroscopy. The proposed method is based on reflectance measurements of a violet compound produced from a spot test reaction between bumetanide and p-dimethylaminocinnamaldehyde (p-DAC) in an acid medium, using filter paper as a solid support. The best conditions for the reaction have been found by experimental design methodologies. All reflectance measurements were carried out at 525 nm, and the linear range was from 1.37 x 10(-4) to 1.37 x 10(-3) mol L(-1), with a correlation coefficient of 0.998. The detection limit was estimated to be 3.98 x 10(-5) mol L(-1). Five commercial medicines containing bumetanide were analyzed by the proposed method. No interferences were observed from the common excipients present in pharmaceutical formulations. The results were favorably compared with those obtained by the United States Pharmacopoeia procedure at 95% confidence level.

An environmentally friendly reflectometric method for ranitidine determination in pharmaceuticals and human urine.

This paper describes an environmentally friendly method for quantitative determination of ranitidine using diffuse reflectance spectroscopy. This method is based on the reflectance measurements of the colored product produced from the spot test reaction between ranitidine and p-dimethylaminocinnamaldehyde (p-DAC), in acid medium, using filter paper as solid support. Experimental design methodologies were used to optimize the optimal conditions. All reflectance measurements were carried out at 590 nm and the linear range was from 1.42x10(-3) to 3.42x10(-2) mol L(-1), with a correlation coefficient of 0.997. The limit of detection was estimated to be 1.09x10(-3) mol L(-1) (R.S.D.=1.9%). The proposed method was successfully applied to the determination of ranitidine in commercial brands of pharmaceuticals and no interferences were observed from the common excipients in formulations. The results obtained by the proposed method were favorably compared with those obtained by an official procedure at 95% confidence level. Additionally, the method was also applied to the determination of ranitidine in human urine showing excellent recoveries (99.6-100.3%).