This study developed a methodology for extracting and speciating CrIII and CrVI in sewage sludge by high performance liquid chromatography, inductively coupled plasma tandem mass spectrometry (HPLC-ICP-MS/MS). The optimal procedure was solid-liquid extraction in a water bath with stirring at 50 °C for 16 h and 50 mmol L−1 ethylenediaminetetraacetic acid (EDTA) extraction phase at pH 9.5. In the validated method, the recovery in the fortification experiment was greater than 70% and the relative standard deviation was less than 7%. Speciation analyses showed that all CrVI was spontaneously reduced to CrIII in the sludge sample. The limits of detection and quantification were 0.060 and 0.20 µg L−1, respectively, and the analyses of CrIII by means of ICP-MS/MS were linear from 0.20 to 50 µg L−1. The extraction efficiency of Cr specie in this validated method improved from 4.09 to 53.3% compared to the EPA 1311 method. The methodology was successfully applied to quantify CrIII in a sludge sample with a lower concentration than that established by European legislation 80568/4225/91.

In this work, the direct determination methodology of glyphosate and aminomethylphosphonic acid (AMPA) by high performance liquid chromatography (HPLC) using inductively coupled plasma with triple quadrupole mass spectrometer (ICP-MS/MS) was compared with the conventional method using diode array detector (HPLC-DAD). Both methods were selective, but the chromatographic analysis using ICP-MS/MS as detector was four times faster than DAD. The methodology using ICP-MS/MS as detector was linear from 27 to 218 µg L-1, while by the conventional method it was 1 to 8 mg L-1. Detection limits of the glyphosate achieved with the HPLC-ICP-MS/MS and HPLC-DAD methods were 8.2 and 300 µg L-1, respectively. The direct determination using ICP-MS/MS as detector showed a lower number of stages in sample preparation because it did not need the derivatization step. Seven real samples were analyzed by HPLC-ICP-MS/MS and the results showed that these analytes were not detected.

The chemical composition of Acacia mearnsii wood extract is described in this paper for the first time. This wood is cultivated in Brazil and has been used to complement the demand for hardwood in the pulp industry. In this study, we performed extractions with acetone (total extracts) and dichloromethane (lipophilic extracts responsible for the pitch formation), with the obtained percentages being 1.68 and 0.68%, respectively. The lipophilic extracts were derivatized and analyzed by Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) before and after alkaline hydrolysis. The results showed that 57 compounds were detected in the lipophilic extracts and these are mainly constituted by fatty acids ca. 32.8 mg kg-1 and sterols 26.9 mg kg-1. These chemical classes have always been present in pitch deposits in the pulp industry. Therefore, these results may be used by pulp mills to establish strategies for pitch control and represent an important advance in the knowledge of A. mearnsii.

Polychlorinated dibenzo-p-dioxins and dibenzofurans are persistent organic pollutants which can mainly be found in the environment in water. These compounds are highly toxic and therefore developing new extraction methodologies that are simpler and cost less is highly desirable. This study aimed to optimize and validate the liquid-liquid extraction with low-temperature partition methodology of 2,3,7,8-tetrachlorodibenzo-p-dioxin and 2,3,7,8-tetrachlorodibenzofuran in water samples. The optimum extraction conditions were 8.0 mL of the acetonitrile and 4.0 mL of the water, homogenized in a vortex for 1 min and then maintained at -20 ºC for 1 h. The analytes recovery percentage was close to 100% and relative standard deviation was less than 7%. The methodology was precise, accurate, linear at 2.4-5.4 µg L-1, and selective, with a quantification limit of 2.4 µg L-1. The optimized methodology was applied in ten real samples and the results showed that these analytes were not detected.

Parâmetros de maturação de frutos de tomate como pH, ºBrix, acidez e teores de licopeno e β-caroteno foram avaliados. Cinco agrotóxicos foram quantificados em extratos orgânicos de tomate em diferentes fases de maturação. A técnica de extração sólido-líquido com partição em baixa temperatura (ESL-PBT) foi utilizada para a obtenção desses extratos orgânicos. O efeito da matriz tomate foi calculado a partir dos resultados da análise por cromatografia gasosa com detector de captura de elétrons (CG-DCE). Correlações entre os parâmetros de maturação e efeito matriz foram estudadas. A correlação entre o teor de carotenoides e o efeito matriz foi elevada para todos os pesticidas estudados. Os resultados indicam que o efeito produzido pela matriz tomate está correlacionada com a presença de licopeno e β-caroteno em extratos orgânicos. A análise de componentes principais (PCA) mostrou que o licopeno, caroteno e a mistura de ambos têm efeitos significativos sobre a resposta cromatográfica de pesticidas.

Some parameters of tomato fruits ripening such as color, pH, ºBrix, acidity and lycopene and β-carotene content were evaluated during the ripening of fruits. Five pesticides were quantified in organic extracts derived from tomatoes at different stages of maturation. The solid-liquid extraction technique with partition at low temperature (SLE-PLT) was used to obtain these organic extracts. The matrix effect of tomato was calculated from the results of analysis by gas chromatography with electron capture detector (GC-ECD). Correlations between maturation parameters and matrix effect were performed. The correlation between the content of carotenoids and matrix effect was high for all pesticides studied. The results indicate that the effect produced by the tomato matrix is correlated with the presence of lycopene and β-carotene in organic extracts. The principal component analysis (PCA) showed that lycopene, carotene and the mixture of both have significant effects on the chromatographic response of pesticides, separating them into distinct groups.