Determination of flavonoids in cultivated sugarcane leaves, bagasse, juice and in transgenic sugarcane by liquid chromatography-UV detection

A high-performance liquid chromatography (HPLC) method with photo-diode array (DAD) detection was developed to separate and quantify flavonoids in sugarcane leaves and bagasse (= the crushed sugarcane refuse from juice extraction), and in sugarcane juice. Sugarcane flavonoids consist of a complex mixture of aglycones and glycosides (including flavonolignan glycosides), and the HPLC-UV method herein proposed is suitable for their quantification as total flavonoids. This method was applied to analyze samples of cultivated sugarcane, commercial juice and transgenic sugarcane leaves. Sugarcane leaves proved a promising source of flavonoids: an average of 1.10 mg of total flavonoids/g plant material was found in fresh leaves. Moreover, the flavonoid content of sugarcane juice (0.6 mg/mL) is comparable to other food sources of flavonoids previously reported. Transgenic sugarcane leaves ("Bowman-Birk" and "Kunitz") were compared with non-modified ("control") plant samples using the proposed HPLC-UV method, which indicated that the content of total flavonoids in transgenic plants is different from that in non-modified sugarcane.     

Dissipation behavior of chlorpyrifos residues and risk assessment in sugarcane fields

As chlorpyrifos is used globally to control pests in sugarcane fields, analysis of its residues on food crops is essential to assess product safety for humans. In this study, chlorpyrifos content in sugarcane plants, soil and juice was determined using a gas chromatography with an electron capture detector. The limit of quantification was 0.01 mg/kg for plant and soil, and 0.01 mg/L for juice. The degradation and residual risk in sugarcane fields after applying chlorpyrifos to two sample sites (Changsha and Danzhou, China) were assessed. Chlorpyrifos concentrations in plants and soil decreased rapidly over time, reaching a degradation rate ranging from 98.82 to 99.25% on day 35. The half‐life of chlorpyrifos in both plants and soil was only 5.97–6.12 days. Regardless of application dosage (standard or high) at a pre‐harvest interval of 60 days, chlorpyrifos was undetectable in the harvested sugarcane. Risk assessment indicated that chlorpyrifos residue in sugarcane did not pose a health risk to humans.     

Estimation of residues of carbofuran and its metabolites in sugarcane and soil by derivatization with 1-fluoro-2,4-dinitrobenzene and gas chromatography with nitrogen-phosphorus detection

Residues of carbofuran and its metabolites were studied in sugarcane plants and soil after application at 1 and 2 kg/ha. The residues of carbofuran and its metabolites were extracted by refluxing with 0.25N HCI, partitioned into dichloromethane, and cleaned up on acidic alumina. The respective 7-phenols of carbofuran, 3-ketocarbofuran, and 3-hydroxycarbofuran were destroyed by treatment with ceric ammonium sulfate, and the residues were derivatized with 1-fluoro-2,4-dinitrobenzene. The derivatives were estimated by gas chromatography with nitrogen-phosphorus detection. The concentration of 3-hydroxycarbofuran in sugarcane plants remained higher and persisted longer than that of the parent compound. Carbofuran-derived residues were not detected in cane juice. Soil samples were found to contain only carbofuran, which declined at a very fast rate that followed a first-order kinetics rate of reaction.     

Determination of pesticides in sugarcane juice employing microextraction by packed sorbent followed by gas chromatography and mass spectrometry

This paper describes the development of a method for the determination of six pesticides (tebuthiuron, carbofuran, atrazine, metribuzine, ametryn, and bifenthrin) in sugarcane juice using microextraction by packed sorbent as the extraction technique. The extraction steps were optimized by factorial design, being the variables pH, ionic strength, desorption solvent and solvent volume optimized for comparisons among sorbent materials. Among the evaluated materials C18‐Chromabond ^® showed better extraction efficiency. A factorial design 2³ with central point was used for the extraction cycles optimization. Draw/eject and washes cycles showed significant improvements in the extraction efficiency when the number of cycles increased. The method was validated and showed a limit of quantification in the range of 2.0–10.0 μg.L^?1. The calibration curves were constructed by weighting models that reduced the sum of absolute residues values and improved determination coefficient. The matrix factor and extraction efficiency were 97.3–77.3% and 27.1–64.8%, respectively. The accuracy was 71.7–106.9%; precision evaluated as the coefficient of variance obtained in intra and inter day analysis was 4.5–15.9%. The method was applied to the determination of pesticide residues in four sugarcane juice samples commercially available in markets from different cities from São Paulo state, Brazil.     

Tracking soil transport to sugarcane industry using neutron activation analysis

Soil as mineral impurity in sugarcane loads impacts the Brazilian sugar-ethanol industry with rising production and maintenance costs as well as decreased productivity. The mechanical harvesting of sugarcane was conceived as a technology with potential to increase the raw material quality thereby has been gradually replacing manual harvesting throughout the country. Instrumental neutron activation analysis was applied for determination of soil tracers in order to compare the performance of both harvesting systems in terms of mineral impurities. There were no significant differences in the amount of soil transported to sugarcane industry despite the technological progress aggregated to mechanical harvesting. However, for both harvesting systems there were significant differences on the amount of such mineral impurity between clay and sandy soils.     

蔗汁酒精废液色素的提取及其抗氧化活性研究

针对蔗汁酒精废液中含有的大量色素物,采用大孔树脂吸附提取色素,对蔗汁酒精废液中色素的提取工艺及其抗氧化活性进行了研究。通过静态吸附实验筛选出吸附树脂D101及对应的洗脱溶剂乙醇。最佳流速为3BV/h,最佳洗脱条件为40%的乙醇在pH6～7范围内进行洗脱。经测定,色素的黄酮含量为茶多酚的27.2%,但对自由基的抑制率却为茶多酚的88.06%,表明蔗汁酒精废液中提取的色素具有较高的抗氧化活性。     

Clean energy from sugarcane bagasse: quality evaluation by neutron activation analysis

The energy from sugarcane is one of the most important in Brazil’s energy matrix and the efficiency of extraction and processing is fully dependent on the quality of the raw material. The soil present in sugarcane was investigate here as a factor that can affect the production of energy. Chemical elements (Fe, Hf, Sc and Th) determined by instrumental neutron activation analysis were used for tracing soil in sugarcane and its derived bagasse. The lower calorific value (LCV) of bagasse demonstrated a good negative correlation (r = ?0.9727) with the ash content of the bagasse, which in turn was positively correlated to the amount of soil in the sugarcane. Therefore, the presence of soil reduces the production of energy from burning bagasse. The proportion of loss in the LCV was just slightly higher than the soil content, i.e. for an soil content of 10 % a reduction of 12.7 % was observed in the LCV.     

Optimization of Levan Production by Cold-Active <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> ANT 179 and Fructooligosaccharide Synthesis by Its Levansucrase

Fructooligosaccharides (FOS) and levan attract much attention due to a wide range of applications in food technology and pharmaceutical and cosmetic industry. Bacillus licheniformis ANT 179, isolated from Antarctica soil, produced levansucrase and levan in a medium containing sucrose as carbon substrate. In this study, characterization of levansucrase and production of short-chain FOS and levan were investigated. Temperature and pH optimum of the enzyme were found to be 60 °C and pH 6.0, respectively. The optimization of fermentation conditions for levan production using sugarcane juice by response surface methodology (RSM) was carried out. Central composite rotatable design was used to study the main and the interactive effects of medium components: sugarcane juice and casein peptone concentration on levan production by the bacterium. The optimized medium with sugarcane juice at 20 % (v/v) and casein peptone at 2 % (w/v) was found to be optimal at an initial pH of 7.0 and incubation temperature of 35 °C for 48 h. Under these conditions, the maximum levan concentration was 50.25 g/L on wet weight basis and 16.35 g/L on dry weight basis. The produced inulin type FOS (kestose and neokestose) and levan were characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) analysis. The study revealed that the levansucrase could form FOS from sucrose. The locally available low-cost substrate such as sugarcane juice in the form of a renewable substrate is proposed to be suitable even for scale-up production of enzyme and FOS for industrial applications. The levan and FOS synthesized by the bacterium are suitable for food applications and biomedical uses as the bacterium has GRAS status and devoid of endotoxin as compared to other Gram-negative bacteria.     

Development of a new stir bar sorptive extraction coating and its application for the determination of six pesticides in sugarcane juice

In this article, a novel polydimethylsiloxane/activated carbon (PDMS‐ACB) material is proposed as a new polymeric phase for stir bar sorptive extraction (SBSE). The PDMS‐ACB stir bar, assembled using a simple Teflon^®/glass capillary mold, demonstrated remarkable stability and resistance to organic solvents for more than 150 extractions. The SBSE bar has a diameter of 2.36 mm and a length of 2.2 cm and is prepared to contain 92 μL of polymer coating. This new PDMS‐ACB bar was evaluated for its ability to determine the quantity of pesticides in sugarcane juice samples by performing liquid desorption (LD) in 200 μL of ethyl acetate and analyzing the solvent through gas chromatography coupled with mass spectrometry (GC‐MS). A fractional factorial design was used to evaluate the main parameters involved in the extraction procedure. Then, a central composite design with a star configuration was used to optimize the significant extraction parameters. The method used demonstrated a limit of quantification (LOQ) of 0.5–40 μg/L, depending on the analyte detected; the amount of recovery varied from 0.18 to 49.50%, and the intraday precision ranged from 0.072 to 8.40%. The method was used in the analysis of real sugarcane juice samples commercially available in local markets.     

Use of Different Extracts of Coffee Pulp for the Production of Bioethanol

Coffee is one of the most important agricultural products in Brazil. More than 50 % of the coffee fruit is not used for the production of commercial green coffee and is therefore discarded, usually ending up in the environment. The goal of this work was to select an efficient process for obtaining coffee pulp extract and to evaluate the use of this extract in bioethanol production. The effects of heat treatment and trituration on the yield and composition of the extract were investigated by measuring the amounts of reducing sugars, starch, pectin, and phenolic compounds. The extraction process was most efficient at room temperature using grinding followed by pressing. Five different fermentation media were tested: sugarcane juice or molasses diluted with water or with coffee pulp extract and a medium with only coffee pulp extract. Batch fermentations were carried out at 30 °C for 24 h, and samples were taken to obtain measurements of the total reducing sugars, cell count, and ethanol concentration. The addition of coffee pulp extract did not influence the fermentation or yeast viability, and it can thus be mixed with sugarcane juice or molasses for the production of bioethanol, with a yield of approximately 70 g/L.     

Analysis of trace levels of sulfonamides in surface water and soil samples by liquid chromatography-fluorescence

Methods are reported for determining six sulfonamides used as veterinary drugs in water and soil samples. Analytes are isolated from water samples by solid-phase extraction on HBL cartridges and pre-concentration factors of up to 250 were obtained. Soil samples are treated using microwave-assisted extraction of analytes with acetonitrile and further clean up by solid-phase extraction. Determination is carried out by high-performance liquid chromatography using fluorimetric detection with precolumn derivatization with fluorescamine. The separation of the derivatized sulfonamides is performed on an octadecyl column using binary gradient elution with acetate buffer/acetonitrile mixtures. For water analysis, the detection limits of the whole process are in the low nanogram per liter level and recovery rates range from 70 to 104%, with standard deviations 2-11%. For soil analysis, extraction efficiency is evaluated using three soil samples with different physicochemical characteristics. Recovery rates range from 60 to 98% and detection limits are between 1 and 6ngg(-1).     

正交试验优化土壤萃取法及常见无机阴离子的离子色谱分析

实验采用超声提取离子色谱法测定土壤中常见无机阴离子的含量,以正交试验优化土壤中阴离子的提取条件。研究土壤粒径、料液比、提取功率、提取时间对土壤中阴离子提取量的影响。结果表明:土壤中阴离子提取的最佳条件为A1B2C3D3。即超纯水为提取液,土壤粒径为180μm,料液比为1:30,超声波作用时间为40 min,提取功率为320W,提取次数为一次。该方法可用于土壤中常见可溶性无机阴离子含量的提取测定。     

Separation of phenolic acids from sugarcane rind by online solid‐phase extraction with high‐speed counter‐current chromatography

Sugarcane rind contains some functional phenolic acids. The separation of these compounds from sugarcane rind is able to realize the integrated utilization of the crop and reduce environment pollution. In this paper, a novel protocol based on interfacing online solid‐phase extraction with high‐speed counter‐current chromatography (HSCCC) was established, aiming at improving and simplifying the process of phenolic acids separation from sugarcane rind. The conditions of online solid‐phase extraction with HSCCC involving solvent system, flow rate of mobile phase as well as saturated extent of absorption of solid‐phase extraction were optimized to improve extraction efficiency and reduce separation time. The separation of phenolic acids was performed with a two‐phase solvent system composed of butanol/acetic acid/water at a volume ratio of 4:1:5, and the developed online solid‐phase extraction with HSCCC method was validated and successfully applied for sugarcane rind, and three phenolic acids including 6.73 mg of gallic acid, 10.85 mg of p‐coumaric acid, and 2.78 mg of ferulic acid with purities of 60.2, 95.4, and 84%, respectively, were obtained from 150 mg sugarcane rind crude extracts. In addition, the three different elution methods of phenolic acids purification including HSCCC, elution–extrusion counter‐current chromatography and back‐extrusion counter‐current chromatography were compared.     

Are physico-chemical soil characteristics key factors to select the polycyclic aromatic hydrocarbons extraction procedure?

The aim of this work was to assess the impact of soil characteristics and constituents in the total extraction of hydrophobic organic pollutants, such as polycyclic aromatic hydrocarbons (PAH), in real polluted soil samples from different sources. Soil samples were obtained from a wood creosote treatment plant, in the vicinity of a metallurgy industry and coal thermal power stations. Soils showed a wide diversity of textures, organic matter (OM) and CaCO₃ content, pH and electrical conductivity to assure representativeness of multiple situations. Two extraction procedures with soft (solid–liquid extraction, SLE) and intense (pressurised liquid extraction, PLE) extraction power were used to determine the total concentration of PAH in soils. Results obtained showed that soil properties affect the effectiveness of the extraction procedures tested. The validation of PAH extraction procedure with a reference soil did not confirm that the procedure was adequate for all kinds of soil. Results showed that OM content and clay were the main soil characteristics that should be taken into account to select the most adequate PAH extraction procedure for any given polluted soil.     

Synthesis of Ammonium-Based Ionic Liquids for the Extraction Process of a Natural Pigment (Betanin)

The use of new synthesized ammonium-based ionic liquids was explored as an alternative to the current process implemented in the betanin extraction from red beet juice, resulting in high yields: 70% and 82%. Betanin is a vegetal pigment that has been applied to a large variety of products in the food industry, which is important, for it can work as a substitute for the red synthetic dyes used nowadays. Additionally, the use of the kosmotropic salt sodium acetate was explored in order to separate the complex formed by the ionic liquid and pigment of interest in a process that combined two techniques: ATPS (aqueous two-phase system) and SOES (salting-out extraction system). The results reveal that the studied techniques could work as a novel process for the extraction of betanin from red beet juice employing ionic liquids, which have not been tested for this purpose in other research.     

Development and validation of a multiresidue method for the simultaneous determination of organophosphorus insecticides and their toxic metabolites in sugarcane juice and refined sugar by gas chromatography with flame photometric detection

A multiresidue method has been developed and validated for the simultaneous determination of organophosphorus insecticides and their toxic metabolites in sugarcane juice and refined sugar by gas chromatography with flame photometric detection. Limits of quantification of the method varied between 0.007 and 0.01 μg/g. Ethyl acetate based extraction followed by dispersive solid‐phase extraction cleanup with primary secondary amine yielded internationally acceptable recoveries of acephate, chlorpyrifos, dichlorvos, monocrotophos, malathion, malaoxon, phorate, phorate‐sulfoxide, phorate‐oxon, phorate‐sulfone, and quinalphos from selected matrices. The recoveries of target analytes from cane juice were 75.55 ± 0.5–102.57 ± 4.2, 77.45 ± 4.7–103.33 ± 3.3, and 80.55 ± 6.6–105.82 ± 9.8% at 0.01, 0.02, and 0.1 μg/g levels of fortification, respectively. The recoveries from cane sugar were 73.24 ± 3.5–104.47 ± 1.9, 75.23 ± 1.5–116.10 ± 3.7, and 70.75 ± 5.7–110.15 ± 2.7%, respectively at 0.01, 0.02, and 0.1 μg/g levels of fortification. Matrix effect and measurement uncertainty were within the permissible limit (less than 20%) as prescribed for pesticide residue analysis.     

Screening and determination of pesticides in soil using continuous subcritical water extraction and gas chromatography-mass spectrometry

In the present work the efficiency of water under subcritical conditions for the extraction of pesticides having a broad spectrum of polarities from soils was evaluated. The pesticides under study were carbofuran, hexachlorobenzene, dimethoate, simazine, atrazine, lindane, diazinon, methylparathion, alachlor, aldrin-R, metholachlor, chlorpyrifos, heptachlor epoxide, dieldrin, endrin, 4,4-DDT and metoxichlor. Optimization studies were carried out using a blank soil (Non-Polluted Soil 1, CLN-1, RTC) and a real soil which were previously spiked with the pesticide mixture and aged for 60 days. A laboratory-made aluminum oven with controlled temperature was used to carry out the leaching process with subcritical water, where it is placed a pre-heater and the extraction cell. The following variables were studied, keeping the pressure controlled about 1200 p.s.i.: the extraction temperature, the time of static and dynamic extraction and the flow-rate of water (1 p.s.i. = 6894.76 Pa). The extraction efficiency of the pesticides increases with the temperature trending to the quantitative extraction at temperatures near to 300 degrees C. After the extraction process, the analytes were transferred quantitatively to 5 ml dichloromethane, before the determination by GC-MS. The results indicate that under the optimized conditions mostly of the analytes are extracted quantitatively in 90 min with recoveries quite similar to those obtained by the standard Soxhlet extraction procedure. Alternatively, by using an extraction time of 25 min, the method can be used as screening for all the pesticides, with recoveries depending on their polarity.     

Ionic liquids as stationary phases in gas chromatography: Determination of chlorobenzenes in soils

The present research focuses on the evaluation of different ionic liquid (IL) stationary phases in gas chromatography. The different IL columns were evaluated in terms of peak resolution (R_s) and peak symmetry for the separation of the chlorobenzenes. The determination of chlorobenzenes in soil samples by means of the optimal IL stationary phase (SLB‐IL82) is proposed as an application. Soil pretreatment was based on a simplified quick, easy, cheap, effective, rugged, and safe extraction procedure and a large injection volume via a programed temperature vaporizer working in solvent vent mode. The retention time of the chlorobenzenes increased as the polarity of the IL column decreased. SLB‐IL82 is the stationary phase that provides the best values as regards R_s and asymmetry factor. Soil sample blanks were spiked with the analytes before subjecting the sample to the extraction process. The existence of a matrix effect was checked and the analytical characteristics of the method were determined in a fortified garden soil sample. The method provided good linearity, good repeatability and reproducibility values, and the LODs were in the 0.1–4.7 μg/kg range. Two fortified soil samples were applied to validate the proposed methodology.     

Extraction optimization by response surface methodology: Purification and characterization of phytosterol from sugarcane (Saccharum officinarum L.) rind

A green, simple, and effective method for the extraction of sugarcane lipids from sugarcane rind was investigated by response surface methodology. The optimum conditions of technological progress obtained through response surface methodology were as follows: liquid‐to‐solid ratio 7.94: 1 mL/g, extraction temperature 50°C and extraction time 5.98 h. The practical sugarcane lipids extraction yield was 6.55 ± 0.28%, which was in good consistence with the predicted extraction yield of 6.47%. The results showed that the sugarcane lipids extraction yield obtained in optimum conditions increased by 1.16～7.28‐fold compared to the yields obtained in single‐factor experiments. After saponification and SPE steps, the nonsaponifiable fraction of sugarcane lipids was analyzed by gas chromatography with mass spectrometry and high‐performance liquid chromatography. β‐Sitosterol, stigmasterol, and campesterol were the prevailing phytosterols in the sample, while fucosterol, gramisterol, stigmast‐7‐en‐3‐ol, (3β,5α,24S)‐, stigmasta‐4,6,22‐trien‐3α‐ol, and cholest‐8(14)‐en‐3β‐ol acetate were also identified as minor steroids. Furthermore, the content of β‐sitosterol and a mixture of campesterol and stigmasterol (quantified by high‐performance liquid chromatography) was 44.18 mg/100 g dry weight and 43.20 mg stigmasterol/100 g dry weight, respectively. Our results indicate that sugarcane rind is a good source of phytosterol.     

Demetalisation of soils by continuous acidified subcritical water extraction

Acidified subcritical water is proposed for the continuous extraction of metals (namely, lead, copper, cadmium, arsenic, selenium and mercury) from soils prior to: (a) continuous derivatisation (by hydride formation for As and Se, and cold vapour formation for Hg) and determination by atomic fluorescence; and (b) determination by Graphite Furnace-Atomic Absorption Spectrometry for Pb, Cu and Cd. Soil samples (5 g) were subjected to 90-min dynamic extraction with water modified with 4% (v/v) HNO(3) at 200 degrees C and 30 bar. A univariate optimisation of the variables related to derivatisation (for As, Se and Hg) and detection (for all of them), and a multifactorial optimisation of the variables affecting the continuous extraction step were performed. A kinetics study of the extraction process was performed in order to control the lowering of metals in the soil. The method was compared with the EPA-3051 reference method. The good reproducibility of the method, together with its safety and low cost, make it a good alternative for the demetalisation of contaminated soil.