Determination of trihalomethanes in drinking water from three different water sources in Florianopolis-Brazil using purge and trap and gas chromatography

The water source to feed the public water system in Florianopolis, Santa Catarina State-Brazil is very diversified and it was used to investigate the formation of trihalomethanes (THM). A strong relationship between the presence of THM and the kind of water source was found. Water sources in contact with vegetation contained higher concentration of total trihalomethanes (TTHM). Water samples from the Cubatao-Piloes system had a mean TTHM value of 59.9 µg L-1 while in Peri Lake, the mean TTHM was 152.3 µg L-1. Samples from the North Shore system, based on wellsprings, had a mean TTHM of 19.4 µg L-1. In the case of natural waters (spring water and wellsprings) THM was not observed. A system that combines purge-and-trap and gas chromatography with an electron capture detector was used in this study. After careful choice of the experimental conditions, the performance of the system was evaluated. Relative standard deviation, limit of detection and limit of quantification are 8-17 %, 0.01-0.03 µg L-1 and 0.03-0.08 µg L-1 respectively. Linear range falls within the range 0.1 to 8.0 µg L-1 for all compounds. Precision ranged between 91.3 and 126.0%

Determination of arsenic in agricultural soil samples using High-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships. BW had a research scholarship from CNPq, Processo No. 303526/2016-5. The authors are also grateful to Analytik Jena for the donation of the HR-CS GF AAS Model contrAA 600 and for financial support.Peer reviewedPostprin

Investigation of chemical modifiers for the determination of cadmium and chromium in fish oil and lipoid matrices using HR-CS GF AAS and a simple ‘dilute-and-shoot’ approach

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships. The present research was mostly financed through Project no. CNPq 406877/2013-0. The authors are also grateful to Analytik Jena for financial support and the donation of the contrAA 600.Peer reviewedPostprin

Returning to Nature for the Design of Sorptive Phases in Solid-Phase Microextraction

Green analytical chemistry principles aim to minimize the negative impact of analytical procedures in the environment, which can be considered both at close (to ensure the safety of the analysts) and global (to conserve our natural resources) levels. These principles suggest, among other guidelines, the reduction/minimization of the sample treatment and the use of renewable sources when possible. The first aspect is largely fulfilled by microextraction, which is considered to be among the greenest sample treatment techniques. The second consideration is attainable if natural products are used as raw materials for the preparation of new extraction phases. This strategy is in line with the change in our production system, which is being gradually moved from a linear model (take–make–dispose) to a circular one (including reusing and recycling as key terms). This article reviews the potential of natural products as sorbents in extraction and microextraction techniques from the synergic perspectives of two research groups working on the topic. The article covers the use of unmodified natural materials and the modified ones (although the latter has a less green character) to draw a general picture of the usefulness of the materials

Coupling solid phase microextraction to complementary separation platforms for metabotyping of E. coli metabolome in response to natural antibacterial agents

The final publication is available at Springer via http://dx.doi.org/10.1007/s11306-016-1111-9Introduction Essential oils are known to possess antimicrobial activity; thus, their use has played an important role over the years in medicine and for food preservation purposes. Objective The effect of clove oil and its major constituents as bactericidal agents on the global metabolic profiling of E. coli bacteria was assessed by means of metabolic alterations, using solid phase microextraction (SPME) as a sample preparation method coupled to complementary analytical platforms. Method E. Coli cultures treated with clove oil and its major individual components were sampled by HS-SPME-GCxGC-ToF/MS and SPME-UPLC-MS. Full factorial design was applied in order to estimate the most effective antibacterial agent towards E. coli. Central composite design and factorial design were applied to investigate parameters influencing metabolite coverage and efficiency by SPME. Results The metabolic profile, including 500 metabolites identified by LC-MS and 789 components detected by GCxGC-ToF/MS, 125 of which were identified as dys-egulated metabolites, revealed changes in the metabolome provoked by the antibacterial activity of clove oil, and in particular its major constituent eugenol. Analyses of individual components selected using orthogonal projections to latent structures discriminant analysis showed a neat differentiation between control samples in comparison to treated samples in various sets of metabolic pathways. Conclusions The combination of a sample preparation method capable of providing cleaner extracts coupled to different analytical platforms was successful in uncovering changes in metabolic pathways associated with lipids biodegradation, changes in the TCA cycle, amino acids, and enzyme inhibitors in response to antibacterial treatment.Natural Sciences and Engineering Research Council (NSERC) of CanadaCNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico), Brazi

Determination of sulfur in biological samples using high-resolution molecular absorption spectrometry in a graphite furnace with direct solid sampling

The determination of sulfur in biological materials using high-resolution continuum source molecular absorption spectrometry and electrothermal vaporization of the carbon monosulfide (CS) molecule has been investigated in detail using direct solid sampling. Best results have been obtained coating the platform with tungsten as a permanent modifier, adding 40 mg Pd in solution as a chemical modifier, and the only sulfur compound that showed sufficient sensitivity and thermal stability to be used for calibration purposes under the conditions established for biological materials was thiourea. A pyrolysis temperature of at least 900 C could be used and the optimum vaporization temperature was 2500 C. Under optimized conditions a limit of detection of 0.015 mg S absolute or 0.03 mg g À1 S in the solid sample, based on a sample mass of 0.5 mg could be obtained; the characteristic mass was m 0 ¼ 18 ng. Five certified biological reference materials have been analyzed using direct solid sampling and calibration against aqueous standards; the results were in agreement with the certified values on a 95% confidence interval

Estudo da eficiência de degradação de tetracloreto de carbono por plasma térmico e caracterização dos produtos formados

Decomposition of carbon tetrachloride in a DC thermal plasma reactor was investigated in argon atmosphere. The operational parameters such as plasma torch power and argon flow rate versus CCl4 conversion were examined. The CCl4 net degradation was determined by GC-FID, the chlorine produced was quantified by iodometric titration, the solid carbon was characterised by Raman spectroscopy and by BET analysis. The solid carbon collected inside de plasma reactor was submitted to solid/liquid extraction and the desorbed species were identified by GC-MS

Determinação de herbicidas usados no cultivo de arroz irrigado na região sul do estado de Santa Catarina através da SPME-GC-ECD

Evaluation of the pollution by the herbicides alachlor, propanil and atrazine in water samples from four rivers in the cities of Turvo and Meleiro, south of Santa Catarina State, was made using the SPME-GC-ECD method. The proposed method was optimized and validated. The correlation coefficients were higher than 0.997 and linear ranges of the analytical curves were 0.1-4; 0.1-2.5 and 0.1-5 µg L-1 for atrazine, alachlor and propanil, respectively. The herbicides were quantified by GC-ECD and identified by GC-MS. Both of the selected rivers presented contamination by at least one of the studied herbicides