Jair Sebastião da Silva Pinto

Hydrolysis of corn oil using subcritical water

This work presents the results of a study on the use of subcritical water as both solvent and reactant for the hydrolysis of corn oil without the use of acids or alkalis at temperatures of 150-280 °C. Corn oil hydrolysis leads to the formation of its respective fatty acids with the same efficiency of conventional methods. Fatty acids form an important group of products, which are used in a range of applications. The confirmation and identification of the hydrolysis products was done by HT-HRGC-FID and HRGC/MS.

Organochlorine pesticides in Piracicaba river basin (São Paulo/Brazil): a survey of sediment, bivalve and fish

The main objective of this paper was to evaluate the level of occurrence of the organochlorine compounds in samples of sediments, bivalves and two fish species collected in the Piracicaba River basin (Sao Paulo, Brazil). The isomers a and g of HCH and Heptachlor were most frequently detected in samples of sediments and specimens of bivalve and fish. Therefore, although the levels of these compounds found were not critically high, they are still found in the environment. This fact suggests that they are still being used, despite the fact that the use of these compounds was outlawed more than twenty years ago.

Sensory and physicochemical characteristics of low sodium salami

The aim of the present study was to develop low sodium salami prepared with pork, low-fat beef and a small quantity of pork back fat (150 g kg−1). Sodium chloride (NaCl) was replaced by potassium chloride (KCl) and calcium chloride (CaCl2), and salamis were tasted to obtain low-salt salami with sensory characteristics similar to those found in commercial ones. Salamis were prepared following seven different treatments. Treatments included five different combinations of KCl and CaCl2 which varied from 5 g kg−1 to 10 g kg−1 and two controls containing high (25 g kg−1) and low (10 g kg−1) concentrations of NaCl. The right level of saltiness of each treatment was evaluated on “just-about-right” (JAR) scales and analyzed by Penalty Analysis. The results showed differences in pH and Aw (water activity) due to NaCl reduction. Salt replacement mixtures of KCl/CaCl2 in salamis did not affect this process technologically (slicing, appearance and texture), and the decrease in Na content was approximately 55 %. Although no significant differences were observed in appearance, treatments differed (p ≤ 0.05) in flavor, texture, and overall liking. As regards salt content of salami, consumers considered treatments with low NaCl content and replacers KCl and CaCl2 (% Na) as having an acceptable level of saltiness. However, this replacement produced a strange taste. Thus, the production of low sodium salamis using salt replacers (KCl and CaCl2) or salamis without replacers with a value higher than 1 % of NaCl can be used effectively without compromising major sensorial attributes.

Hidrólise do óleo de Azadirachta indica em água subcrítica e determinação da composição dos triacilglicerídeos e ácidos graxos por cromatografia gasosa de alta resolução a alta temperatura e cromatografia gasosa de alta resolução acoplada à espectrometria de massas

The development of modern analytical tools plays an important role in quality control. The main purpose of this study was to explore the use of subcritical water as a versatile analytical tool, employed simultaneously as a reagent and solvent, as well as the application of high temperature-high resolution gas chromatography (HT-HRGC) to develop a procedure for the analysis of triacylglycerides and fatty acids in Azadirachta indica A. Juss. (Neem) oil without the need for solvents, chemical reagents, or catalytic agents. The developed method presented satisfactory results and is in agreement with the concepts of Green Analytical Chemistry (GAC).

Design, construction and evaluation of a simple pressurized solvent extraction system

This work describes the construction and testing of a simple pressurized solvent extraction (PSE) system. A mixture of acetone:water (80:20), 80 oC and 103.5 bar, was used to extract two herbicides (Diuron and Bromacil) from a sample of polluted soil, followed by identification and quantification by high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The system was also used to extract soybean oil (70 oC and 69 bar) using pentane. The extracted oil was weighed and characterized through the fatty acid methyl ester analysis (myristic (< 0.3%), palmitic (16.3%), stearic (2.8%), oleic (24.5%), linoleic (46.3%), linolenic (9.6%), araquidic (0.3%), gadoleic (< 0.3%), and behenic (0.3%) acids) using high-resolution gas chromatography with flame ionization detection (HRGC-FID). PSE results were compared with those obtained using classical procedures: Soxhlet extraction for the soybean oil and solid-liquid extraction followed by solid-phase extraction (SLE-SPE) for the herbicides. The results showed: 21.25 ± 0.36% (m/m) of oil in the soybeans using the PSE system and 21.55 ± 0.65% (m/m) using the soxhlet extraction system; extraction efficiency (recovery) of herbicides Diuron and Bromacil of 88.7 ± 4.5% and 106.6 ± 8.1%, respectively, using the PSE system, and 96.8 ± 1.0% and 94.2 ± 3.9%, respectively, with the SLP-SPE system; limit of detection (LOD) and limit of quantification (LOQ) for Diuron of 0.012 mg kg-1 and 0.040 mg kg-1, respectively; LOD and LOQ for Bromacil of 0.025 mg kg-1 and 0.083 mg kg-1, respectively. The linearity used ranged from 0.04 to 1.50 mg L-1 for Diuron and from 0.08 to 1.50 mg L-1 for Bromacil. In conclusion, using the PSE system, due to high pressure and temperature, it is possible to make efficient, fast extractions with reduced solvent consumption in an inert atmosphere, which prevents sample and analyte decomposition.

Design and construction of an on-line SPE-SFE-CGC system

The construction of an on-line SPE-SFE-CGC system is described. The home-made system is of low cost and of easy construction and maintenance, making possible the analysis of organic micropollutants in liquid samples such as water in a fraction of the time spent using traditional methods.

Pressurized Liquid Extraction of Brazilian Coal Followed by the Extracts Characterization by Gas Chromatography Coupled to Mass Spectrometry

This work reports a study on the use of Pressurized Liquid Extraction (PLE) for the selective extraction of organic compounds (aliphatic hydrocarbons - AHs, polycyclic aromatic hydrocarbons - PAHs and polycyclic aromatic compounds - PACs) from high-ash Brazilian coal. A homemade PLE system was built and solvents of different polarities (hexane, toluene and ethanol) were employed to extract the organic compounds from coal samples at a pressure of 10 MPa, under temperatures of 80°C and 200°C and extraction times up to 120 min. The selectivity of the extraction process was evaluated by a well-established methodology employed for the characterization of coal extracts (Preparative Liquid Chromatography - PLC 8). The fractions obtained in the PLC-8 method were dried and, after, quantified by gravimetry. Results showed that the proposed method of extraction was selective for the extraction of AHs using hexane at the temperature of 80°C and for the extraction of PAHs at 200°C. Additionally, the method showed to be selective for the extraction of PACs using ethanol at both studied temperatures. The AHs and PAHs fractions were also analyzed by GC-MS, showing that the first was composed mainly by low molecular weight compounds (<31 carbons) while the second by pyrenes, fluoranthenes, crysenes, benzopyrenes, perylenes and benzofluoranthenes. The present method showed to be a powerful tool for selective extraction of organic compounds from coal samples with simplicity, low quantity of solvent and filling other the requirements to be considered a greener method of extraction.