Brazilian vodkas have undetectable levels of ethyl carbamate

While in Europe vodka is mainly derived from potatoes or cereals, a large proportion of Brazilian vodka is likely obtained from sugarcane, which contains ethyl carbamate (EC) precursors. EC, in addition to several other contaminants and congeners, were investigated in 32 samples of Brazilian vodka. All samples complied with the Brazilian regulations for congeners and contaminants, having EC content below 0.01 mg/L (detection limit). These results are probably related to the processing of vodka, in particular the use of extractive and rectifying stainless steel distillation columns, which allow the production of high strength spirits with low levels of congeners and contaminants.

Avaliação da lixiviação do cádmio e níquel provenientes da degradação de baterias níquel-cádmio em uma coluna de solo

Spent nickel-cadmium (Ni-Cd) batteries and salts of nickel and cadmium were placed in two different columns of soil for a period of two years. A leaching solution was passed through them at ambient temperature in this period. The behavior of metals in each column was then evaluated. Under the conditions of the experiment, cadmium and nickel demonstrated the potential to contaminate and affect the natural cycles of soil. The disposal of Ni-Cd batteries directly to the soil also increased the concentration of nickel (349 mg kg-1) and cadmium (2890 mg kg-1), sometimes exceeding the intervention values defined in CONAMA resolution 420/09.

Optimization of chromatographic conditions and comparison of extraction efficiencies of four different methods for determination and quantification of pesticide content in bovine milk by UFLC-MS/MS

This paper describes the optimization of a multiresidue chromatographic analysis for the identification and quantification of 20 pesticides in bovine milk, including three carbamates, a carbamate oxime, six organophosphates, two strobilurins, a pyrethroid, an oxazolidinedione, an aryloxyphenoxypropionate acid/ester, a neonicotinoid, a dicarboximide, and three triazoles. The influences of different chromatographic columns and gradients were evaluated. Furthermore, four different extraction methods were evaluated; each utilized both different solvents, including ethyl acetate, methanol, and acetonitrile, and different workup steps. The best results were obtained by a modified QuEChERS method that lacked a workup step, and that included freezing the sample for 2 hours at -20 ºC. The results were satisfactory, yielding coefficients of variation of less than 20%, with the exception of the 50 µg L-1 sample of famoxadone, and recoveries between 70 and 120%, with the exception of acephate and bifenthrin; however, both analytes exhibited coefficients of variation of less than 20%.

CONSTRUÇÃO DE UM DISPOSITIVO DE PRESSURIZAÇÃO A VÁCUO PARA A PREPARAÇÃO DE FASES ESTACIONÁRIAS MONOLÍTICAS VIA PROCESSO SOL-GEL

The filling of capillaries via the sol-gel process is growing. Therefore, this technical note focuses on disseminating knowledge acquired in the Group of Analytical Chemistry and Chemometrics over seven years working with monolithic stationary phase preparation in fused silica capillaries. We believe that the detailed information presented in this technical note concerning the construction of an alternative high pressurization device, used to fill capillary columns via the sol-gel process, which has promising potential for applications involving capillary electrochromatography and liquid chromatography in nano scale, may be enlightening and motivating for groups interested in developing research activities within this theme.

CROMATOGRAFIA POR INTERAÇÕES HIDROFILICAS (HILIC): ESTADO DA ARTE E APLICAÇÕES

Hydrophilic interaction liquid chromatography (HILIC) has been gaining increased attention for its effective separation of highly polar compounds, which include carbohydrates, amino acids, pharmaceutical compounds, proteins, glycoproteins, nucleosides, etc. Polar compounds are usually poorly retained on reverse-phase liquid chromatography (RP-HPLC) columns or have poor solubility in the apolar mobile phase of normal-phase high performance liquid chromatography (NP-HPLC). Since HILIC uses organic solvents such as ACN or MeOH ( > 70%), also used in RP-HPLC and polar stationary phases similar to NP-HPLC (bare silica, diol, amino, amide, saccharide, zwitterionic stationary phases, etc.), it represents a hybrid of the two separation modes. The high organic content in the MP leads to good compatibility with mass spectrometry (MS), increasing the detectivity. This review describes the fundamentals of HILIC and highlights some interesting applications.

Chiral separations of mandelic acid by HPLC using molecularly imprinted polymers

Styrene is used in a variety of chemical industries. Environmental and occupational exposures to styrene occur predominantly through inhalation. The major metabolite of styrene is present in two enantiomeric forms, chiral R- and S- hydroxy-1-phenyl-acetic acid (R-and S-mandelic acid, MA). Thus, the concentration of MA, particularly of its enantiomers, has been used in urine tests to determine whether workers have been exposed to styrene. This study describes a method of analyzing mandelic acid using molecular imprinting techniques and HPLC detection to perform the separation of diastereoisomers of mandelic acid. The molecularly imprinted polymer (MIP) was prepared by non-covalent molecular imprinting using (+) MA, (-) MA or (+) phenylalanine, (-) phenylalanine as templates. Methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) were copolymerized in the presence of the template molecules. The bulk polymerization was carried out at 4ºC under UV radiation. The resulting MIP was grounded into 25~44¼m particles, which were slurry packed into analytical columns. After the template molecules were removed, the MIP-packed columns were found to be effective for the chromatographic resolution of (±)-mandelic acid. This method is simpler and more convenient than other chromatographic methods.

Jatkuvatoiminen ioninvaihto ja kompleksoituvien metallien sorptio kloridiympäristössä

Työn tarkoituksena oli tutkia kompleksoituvien metallien erotusta kloridiliuoksesta ioninvaihdolla. Kirjallisessa osassa perehdyttiin metallikompleksien muodostumiseen, ja erityisesti hopean, kalsiumin, magnesiumin, lyijyn ja sinkin muodostamiin komplekseihin kloridin ja nitraatin kanssa. Kirjallisessa osassa käsiteltiin myös metallien erottamista kiintopetikolonneissa jatkuvatoimisilla ioninvaihtomenetelmillä. Tässä työssä jatkuvatoimisen ioninvaihdon prosessivaihtoehdot jaoteltiin pyöriviin ja paikallaan pysyviin kolonneihin, sekä tarkasteltiin eri prosessivaihtoehtoja kolonnien kytkentöjen suhteen. Työn kokeellisessa osassa tutkittiin kahdenarvoisten metallien erottamista yhdenarvoisista metalleista sekä luotiin koedataa vastaavanlaisen erotusprosessin simulointiin. Kokeissa käytettiin anioninvaihtohartsia ja kelatoivaa selektiivistä ioninvaihtohartsia. Kahdenarvoisen kalsiumin, magnesiumin, lyijyn ja sinkin adsorptiota hartseihin tutkittiin tasapaino-, kinetiikka- ja kolonnikokeilla. Anioninvaihtohartsilla tehtyjen tasapaino- ja kolonnikokeiden tulokset osoittivat, että hartsi adsorboi tehokkaasti sinkkiä kloridiliuoksista, koska sinkki muodostaa stabiileja anionisia klorokomplekseja. Muiden tutkittujen kahdenarvoisten metallien adsorptio hartsiin oli huomattavasti vähäisempää. Tulosten perusteella tutkittu anioninvaihtohartsi on hyvä vaihtoehto sinkin erottamiseen muista tutkituista kahdenarvoisista metalleista kloridiympäristössä. Kelatoivalla hartsilla tehdyt tasapaino- ja kolonnikokeet osoittivat, että hartsi adsorboi kloridiliuoksista hyvin kahdenarvoista kalsiumia, magnesiumia, lyijyä ja sinkkiä, mutta ei adsorboi yhdenarvoista hopeaa. Tulosten perusteella kahdenarvoisten metallien erottaminen yhdenarvoisista metalleista voidaan toteuttaa kokeissa käytetyllä kelatoivalla ioninvaihtohartsilla.

SMB-laitteiston suunnittelu hydrometallurgisiin sovelluksiin

Työn tarkoituksena oli suunnitella, ohjelmoida ja koekäyttää SMB-laitteisto (Simulated Moving Bed) hydrometallurgisiin erotuksiin. Simuloitu liikkuvapeti saadaan aikaan vaihtamalla sisään- ja ulostuloporttien paikkaa nestevirran suuntaan. Tällöin aikaansaadaan kiintoaineen vastavirtaus minkä johdosta erotustehokkuus kasvaa. Komponenttien retentiotaipumuseroista johtuen komponentit liikkuvat eri nopeuksilla kolonnijärjestelmässä. Enemmän pidättäytyvät komponentit liikkuvat nestevirtaa vastaan ja vähemmän pidättäytyvät komponentit nestevirran mukana. Hydrometallurgiassa vastavirtauksen käyttöä ei ole tieteellisissä julkaisuissa käsitelty laajalti ja saatavilla oleva informaatio onkin kaupallisten yritysten tuottamaa. Hydrometallurgiassa vastavirtausta käyttävissä ioninvaihtolaitteistoissa hyödynnetään irrallisia regenerointivyöhykkeitä. Venttiilijärjestelmän osalta päädyttiin ratkaisuun jossa käytetään yhtä kiertoventtiiliä kullekin virralle, minkä lisäksi kolonnien väleillä käytetään solenoidiventtiiliä. Tämä järjestelmä mahdollistaa yleisimpien SMB-menetelmien käytön mukaan lukien irralliset vyöhykkeet. Laitteiston ohjauksesta vastaa LabVIEW 2010:llä ohjelmoitu ohjelmisto, joka sisältää kaikkien tarvittavien laitteiden ohjausrutiinit. Se mahdollistaa venttiilien synkroniset ja epäsynkroniset vaihdot. Laitteiston puhdistusta varten on ohjelmistoon rakennettu oma rutiini venttiilejä varten. Pumppujen osalta ohjelmisto mahdollistaa vakiovirtauksen sekä lineaaristen ja porrasmuotoisten gradienttien käytön. Ongelmatilanteita varten ohjelmisto valvoo pumppujen ja venttiilien toimintaa ja pysäyttää laitteiston tarvittaessa. Koekäytön avulla pystyttiin todentamaan laitteiston toimivuus.

The position effect of structural Eucalyptus round timber on the flexural modulus of elasticity

Round timber has great use in civil construction, performing the function of beams, columns, foundations, poles for power distribution among others, with the advantage of not being processed, such as lumber. The structural design of round timber requires determining the elastic properties, mainly the modulus of elasticity. The Brazilian standards responsible for the stiffness and strength determination of round timber are in effect for over twenty years with no technical review. Round timber, for generally present an axis with non-zero curvature according to the position of the element in the bending test, may exhibit different values of modulus of elasticity. This study aims to analyze the position effect of Eucalyptus grandis round timber on the flexural modulus of elasticity. The three-point bending test was evaluated in two different positions based on the longitudinal rotation of the round timber element. The results revealed that at least two different positions of the round timber element are desired to obtain significant modulus of elasticity.

Spatial variability of soil physical properties in two management systems in sugarcane crop

The aim of this study was to characterize the spatial variability of soil bulk density (Bd), soil moisture content (θ) and total porosity (Tp) in two management systems of sugarcane harvesting, with or without burning, in a Haplustox soil, in the 0-0.20 m layer. The study area is located in Rio Brilhante, state of Mato Grosso do Sul, Brazil, in Eldorado Sugar Mill. The plots have presented 180 m length, and 145.6 m width, totaling 90 points distributed in the form of a grid of nine rows by ten columns, with points spaced 20 m from its neighbor. Soil samples were collected at 0-0.20 m layer in 2007/2008 and 2008/2009 crops. The harvest with burning system had a higher density compared to mechanized harvest, in the two study periods. The moisture content as well as the porosity increased proportionally with the decrease of the density of the harvest burning system compared to the mechanized.

Influence of vinasse application in hydraulic conductivity of three soils

The potassium ion, present in great amount in the vinasse because it is a monovalent cation, has the characteristic of promoting the dispersion of clay particles, in the same way as the sodium, causing a reduction in the pore space of the soil and, in its turn, reducing its permeability. To evaluate this effect of reduction by application of vinasse to the soil, an experiment was conducted for three different soils, with the objective of evaluating the effect of the application of different doses of vinasse on hydraulic conductivity of saturated soil and verifying its possible chemical changes of these soils. For that, it was used PVC columns (in a scheme of constant head permeameter to obtain the values of hydraulic conductivity of saturated soil), filled with three soils - Dark Red Latosol (DRL), Purple Latosol (PL) and Eutrophic Red Nitossol (ERN) - , in which were applied four doses of vinasse (0, 150, 300 and 450m³ ha-1), distributed in a completely randomized design with a 3x4 factorial scheme with three replications. The results evidenced that only the Dark Red Latosol (DRL) showed a reduction in the values of hydraulic conductivity of saturated soil, and in front of the application of vinasse, up to 300m³ ha-1, it was observed an increase in the concentrations of potassium, calcium and cation exchange capacity (CEC) ions.

Construction and calibration of TDR probes for volumetric water content estimation in a Distroferric Red Latosol

The determination of volumetric water content of soils is an important factor in irrigation management. Among the indirect methods for estimating, the time-domain reflectometry (TDR) technique has received a significant attention. Like any other technique, it has advantages and disadvantages, but its greatest disadvantage is the need of calibration and high cost of acquisition. The main goal of this study was to establish a calibration model for the TDR equipment, Trase System Model 6050X1, to estimate the volumetric water content in a Distroferric Red Latosol. The calibration was carried out in a laboratory with disturbed soil samples under study, packed in PVC columns of a volume of 0.0078m³. The TDR probes were handcrafted with three rods and 0.20m long. They were vertically installed in soil columns, with a total of five probes per column and sixteen columns. The weightings were carried out in a digital scale, while daily readings of dielectric constant were obtained in TDR equipment. The linear model θν = 0.0103 Ka + 0.1900 to estimate the studied volumetric water content showed an excellent coefficient of determination (0.93), enabling the use of probes in indirect estimation of soil moisture.

Effect of companion ion on nitrate displacement through transport parameters analysis

Nitrate is the main form of nitrogen associated with water contamination; the high mobility of this species in soil justifies the concern regarding nitrogen management in agricultural soils. Therefore, the objective of this research was to assess the effect of companion cation on nitrate displacement, by analyzing nitrate transport parameters through Breakthrough Curves (BTCs) and their settings made by numerical model (STANMOD). The experiment was carried out in the Soil and Water Quality Laboratory of the Department of Biosystems Engineering, "Luiz de Queiroz" College of Agriculture in Piracicaba (SP), Brazil. It was performed using saturated soil columns in steady-state flow condition, in which two different sources of inorganic nitrate Ca(NO3)2 and NH4NO3 were applied at a concentration of 50 mg L-1 NO3-. Each column was filled with either a Red-Yellow Oxisol (S1) or an Alfisol (S2). Results are indicative that the companion ion had no effect on nitrate displacement. However, nitrate transport was influenced by soil texture, particle aggregation, solution speed in soil and organic matter presence. Nitrate mobility was higher in the Alfisol (S2).

Arvometallien liuospuhdistus jatkuvatoimisella ioninvaihdolla

Työn tarkoituksena oli tutkia arvometalleja sisältävän liuoksen puhdistamista jat-kuvatoimisella ioninvaihdolla. Teoriaosassa käsitellään ioninvaihdon periaate, sekä jatkuvatoimisen ioninvaihdon laiteratkaisuja ristivirta- ja vastavirtasysteemeissä. Lopuksi esitellään Simuloidun liikkuvapedin (SMB) virtausnopeuksien laske-miseksi käytettävä kolmiomenetelmä. Kokeellisen osan tarkoituksena on demonstroida laboratorioon rakennetun jatku-vatoimisen ioninvaihtimen, Simuloidun liikkuvapedin, käyttö arvometallia sisäl-tävän liuoksen puhdistamiseksi kahdenarvoisista metalli-ioneista. Kokeissa käy-tettiin hopeaa sisältävää NaCl-liuosta, josta pyrittiin puhdistamaan Mg2+, Ca2+, Pb2+ ja Zn2+-ionit ekstraktina. Laitteistolla suoritettiin kolme ajoa, joista kaksi edusti vastavirtasysteemiä ja yksi ristivirtasysteemiä. Ensimmäisessä vastavirta-ajossa sekä ekstrakti että raffinaattin erottuva hopealiuos tulivat puhtaina. Toisessa vastavirta-ajossa pyrittiin parantamaan tuottavuutta nostamalla syötön virtausnopeutta, jolloin raffinaatin puhtaus kärsi Pb2+ ja Mg2+-ionien kulkeutuessa liuosfaasin mukana raffinaattiin. Ristivirta-ajossa vain yksi kolmesta raffinaatista saavutti 100 % puhtauden. Kokeet osoittivat, että Mg2+, Ca2+, Pb2+ ja Zn2+-ionien erottaminen hopeaionista on mahdollista käyttämällämme SMB-laitteistolla. Tuottavuuden parantaminen syötön virtausnopeutta nostamalla kuitenkin heikentää puhtautta. Cross-flow-systeemin erilleenkytkettyjen kolonnien ansioista painehäviö on pienempi, mikä mahdollistaa korkeammat virtausnopeudet, mikäli ei vaadita 100 % puhtautta.

Leaching of Picloram in ultisol under different rainfall volumes

The present study aimed to evaluate the leaching potential of Picloram in Ultisol columns under different rainfall amounts. For such, 30 treatments were evaluated (one soil associated with three levels of rainfall and ten depths).The experiments were arranged in a split-plot design, in a completely randomized design, with four replications. PVC columns of 10 cm in diameter and 50 cm in length were filled with these soils, moistened, and placed upright for 48 hours to drain the excess water. The herbicide was applied and rainfall simulations were carried out at specified intensities, according to the treatments, to force Picloram leaching. After 72 hours, all the columns were arranged in a horizontal position and opened lengthwise. Then, soil sampling was carried out every 5 cm of depth for subsequent herbicide extraction and quantification and analysis by high performance liquid chromatography. The remaining soil samples were placed in plastic pots, and, at the respective depths, the indicator species Cucumis sativus was sown. Twenty-one days after the emergence (DAE) of the indicator plants, evaluations were conducted to verify the symptoms of toxicity caused by Picloram in the plants. It was concluded that Picloram leaching is directly dependent on the volume of rain applied. The herbicide reached the deepest regions in the soil with the highest intensity of rain. The results obtained by bioassay were in agreement with those found by liquid chromatography.