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Pesticides are traditionally analyzed using conventional gas chromatography. When fast chromatography is associated with comprehensive two-dimensional gas chromatography (GC × GC), the resulting method presents high-resolution separation associated with a higher chromatographic speed. In the present work, a method for pesticide analysis in sediment samples was developed using quick, easy, cheap, effective, rugged, and safe extraction (QuEChERS) and a hyperspeed GC × GC separation. The QuEChERS procedure reported in the literature was extended to incorporate the analytes tetrachloro-m-xylene, decachlorobiphenyl, trans-chlordane, chlordane, endosulfan lactone, and endosulfan ether. To understand the chromatographic method improvement achieved, the recent concept of average theoretical peak time (ATPT) was used. The ATPT improved from that of the traditional GC × GC separation to the proposed method, and the separation speed can be classified as a hyperspeed separation. The limit of detection and quantitation of the compounds in the standard mix ranged from 0.39 to 17.96 µg L

RESUMO A representatividade da amostragem é fundamental para embasar a tomada de decisão, uma vez que a heterogeneidade da matriz é o principal fator para incerteza dos dados nos estudos de gerenciamento de áreas contaminadas. Neste estudo, coletaram-se 112 amostras de solo superficial em malha quadrada de 1 x 1 m, em uma área 15 x 6 m, no campus regional de Resende da Universidade do Estado do Rio de Janeiro. Anteriormente, no terreno funcionaram empresas de produção de filmes radiográficos e purificação de prata metálica. As amostras de solo foram analisadas por pXRF, método de screening para metais. Com base nos dados levantados, calculou-se, por meio de métodos estatísticos, a quantidade de amostras que permitiriam uma caracterização representativa da área, considerando um erro relativo de 20% para dois intervalos de confiança: 95 e 80%. As análises indicaram concentrações superiores aos valores de referência para os parâmetros prata, mercúrio, chumbo, selênio e zinco. Os resultados de mercúrio possivelmente referem-se a ruído espectral, não estando relacionados ao histórico de uso e ocupação. Os coeficientes de variação das concentrações dos elementos analisados variaram de 132 a 225%. Considerando uma distribuição lognormal, calcularam-se 76 amostras para o maior intervalo de confiança e 53 para o menor. Isso seria o equivalente a transectos com espaçamentos de 1,47 e 2,11 m. Os resultados ratificam a necessidade de investigações de alta resolução nas áreas fonte, conforme recomendado pela Decisão de Diretoria da Companhia Ambiental do Estado de São Paulo nº 038/2017/C (DD-038). ABSTRACT The representativeness of the sampling is fundamental to support decisions, since the heterogeneity of the matrix is the main factor for data uncertainty in contaminated areas management studies. In this study, 112 surface soil samples were collected in a square mesh of 1 x 1 m, in an area of 15 x 6 m, at the Campus Regional de Resende (CRR) of Universidade do Estado do Rio de Janeiro (UERJ). Previously, companies of radiographic films production and metallic silver purification operated in this area. The soil samples were analyzed by pXRF, a screening method for metals detection. Based on the data collected, the number of samples that would allow a representative characterization of the area was calculated, using statistical methods, considering a relative error of 20% for 80 and 95% confidence intervals. The analyses indicated concentrations higher than the reference values for the parameters silver, mercury, lead, selenium, and zinc. The results of mercury possibly refer to spectral noise, not being related to the history of use and occupancy. The coefficient of variation of the soil obtained ranged from 132 to 225%. Considering a lognormal distribution, 76 samples were calculated for the highest confidence interval and 53 for the lowest. This would be the equivalent of transects with spacings of approximately 1.47 and 2.11 m. The results confirm the need for high resolution investigations in the source areas, as recommended by the Executive Board Decision of CETESB No. 038/2017/C (DD-038).

The definition of a chromatographic analysis speed based simply on analysis time is an outdated concept to define conventional chromatography, fast chromatography, and emerging high-resolution techniques such as comprehensive two-dimensional and comprehensive three-dimensional gas chromatography. Here, the metric average theoretical peak time (ATPT) is proposed for separation speed, considering conventional and multidimensional separations. ATPT can be defined as the time (in ms per peak) needed to elute a theoretical peak in a chromatographic system. Using this metric, it is possible to define ranges, proposed for a normal speed (ATPT higher than 4000 ms/peak), high speed (ATPT range from 600 to 4000 ms/peak), very high speed (ATPT range from 200 to 600 ms/peak), hyper speed (ATPT range from 3.3 to 200 ms/peak) and ultra high speed chromatography (ATPT lower than 3.3 ms/peak), that combines time and efficiency metrics. This metric was applied in several contexts to demonstrate its robustness to evaluate chromatographic separations for different techniques and analytical conditions. Applications also demonstrate the advantages of the use of ATPT as a method development metric tool.

Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC/TOFMS) is used to characterize complex bio-oil samples because of the high peak capacity associated with the high acquisition rate and mass spectra deconvolution capability of TOFMS. A recent application of fast GC × GC for this type of analysis improved sample throughput while achieving the same peak capacity without the use of cryogenic liquids. This work evaluates the effect of the TOFMS data acquisition rate on the quality of the analytical information obtained by GC × GC/TOFMS. In the analysis of coconut fiber bio-oil under fast GC × GC/TOFMS conditions, use of high data acquisition rates (200–300 Hz) increases the number of identifiable peaks by more than 50% compared with that achieved at the conventional rate of 100 Hz. The acquisition rate can affect the peak capacity by a factor of 3 or more. This is the first study to demonstrate the importance of optimizing the data acquisition rate, a parameter that has previously been neglected in the literature, in GC × GC/TOFMS development.

Com o objetivo de desenvolver novas tecnologias que impactem diretamente na realidade ambiental do Brasil no âmbito do gerenciamento de resíduos sólidos e na educação socioambiental, o projeto Síntese é desenvolvido pelo Departamento de Engenharia Química e Ambiental e por alunos do curso de Engenharia Química da Faculdade de Tecnologia da Universidade do Estado do Rio de Janeiro, Brasil. Para tal, utiliza-se como grupo focal a população do próprio campus regional de Resende, onde o projeto é desenvolvido. Com base nos tipos de resíduos gerados pelo campus, são propostas alternativas para o tratamento dos mesmos, desenvolvimento de tecnologias que possam ser aplicadas à realidade da sociedade brasileira e de medidas que estimulem a sociedade a fazer parte do processo de tratamento dos resíduos, gerando um impacto social e de responsabilidade ambiental. A etapa inicial do trabalho desenvolvido pelo projeto é o levantamento dos tipos de resíduos gerados pela população do campus para que sejam determinadas as áreas de atuação prioritárias para o desenvolvimento de soluções e vertentes tecnológicas. Após esta etapa, são determinadas divisões de desenvolvimento para cada grande grupo de resíduo do campus, posteriormente visando realidade industrial da região. Foi observado que a maior parte dos resíduos gerados eram de materiais recicláveis, seguido de materiais não recicláveis, assim como o observado em outras universidades, a maior divergência se deu na discrepância de material compostável recolhido.

In Brazil, the policy for disposing industrial sludge is changing from an emphasis on using controlled landfills to other treatment or co-processing methods; however, the monitoring of organic pollutants is not mandatory. The present study evaluated two general screening methods for organic pollutants in sludge generated in an automotive industrial complex in southern Brazil. The screening was performed using Soxhlet and sonication extractions and Gas Chromatograph coupled with Quadrupole Mass Spectrometry (GC/qMS). It was concluded that both techniques were effective and that most of the compounds identified were alkanes, phenols and esters. Important pollutants were detected in the sludge, which confirms the necessity of monitoring this type of residue.

Recycling of paper in industrial scale has become an established practice worldwide. In this work, organic compositions of three different kinds of sludge generated in recycle paper industry were studied, and the incorporation of one of those sludge in briket was also investigated. The characterization of organic compounds in sludge samples and briket was performed using Gas Chromatography coupled with Mass Spectrometry after a Soxhlet extraction. Different chemical classes were identified in each type of sludge, but just the sludge composed by cellulose residue did not presented polyaromatic hydrocarbons. Four formulations of sludge incorporated with charcoal for briket production were evaluated.

Nitrogen (N)-containing compounds are naturally present in petroleum, and they are responsible for several deleterious effects that reduce the quality of products and negatively affect the processes involved in the upgrading of feedstock. The speciation of such compounds in petroleum heavy fractions is still a challenge. In the present work, N-containing compounds were characterized in heavy gas oil (HGO) fractions using a solid−liquid fractionation scheme and comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. Classification and identification of compounds were carried out based on seven different categories of analytical information viz. retention times in first and second dimensions, analytical standards co-injection, the structured pattern of the separation space, the structured pattern of the separation space with the selection of specific m/z values, the library mass spectra match factor, and the characteristic deconvoluted mass spectra. All of these inter...

In this work the higher peak capacity and resolution of comprehensive two-dimensional gas chromatography (GC × GC) has been successfully applied, for the first time, to tentatively identify several polar organic compounds of organic extracts of aqueous phases resulting from microwave demulsification process of water-in-crude oil emulsions. Results have shown that higher temperatures and longer exposure time to microwave irradiation produced water phases with a wider variety of polar organic compounds. The microwave process showed to be suitable for the extraction of several polar compounds classes of petroleum. The proposed microwave extraction method and GC × GC identification of polar compounds of petroleum samples are of practical interest for the petrochemical industry due to corrosion and related problems associated with these polar compounds in refinery equipments. The GC × GC/time-of-flight MS technique shows to be very important in the total separation of different classes of compounds and allows the identification of many compounds in these classes.

In the present work, the composition of volatile oil from leaves of Eucalyptus dunnii was studied using comprehensive two-dimensional gas chromatography (GC × GC) techniques. Structurally related compounds were found to elute mainly in specific regions of the two-dimensional space, showing orderly distribution with chemical class. Mass spectra of essential oil components were obtained from two different mass spectrometry detection methods: quadrupole (qMS) and time-of-flight (TOFMS), using the same GC × GC system under the same chromatographic conditions. Higher values of Similarity (average S of 914 with TOFMS compared to 880 with qMS) and Reverse (average R of 944 with TOFMS compared to 881 with qMS) were obtained with GC × GC/TOFMS showing its superior performance, which was most likely due to better sensitivity and resolution arising from the TOFMS system, and lack of spectral bias. Also, the number of compounds found in E. dunnii essential oil was 15% higher when TOFMS was used. Most of these are lower abundance components or exhibit low quality mass spectra; this supports the improved sensitivity obtained with TOFMS. A linear relationship (r2 = 0.998) between experimental retention indices (LTPRI) of 30 standard compounds obtained with GC × GC/TOFMS and GC with flame ionization detection literature retention indices is reported as an aid for compound identification.

Comprehensive Multidimensional Chromatography is a relatively new analytic technique, which is receiving growing attention in many parts of the world, including recently in Brazil. This work presents terms in Portuguese which are commonly used in Comprehensive Multidimensional Chromatography in order to help standardize the vocabulary employed in this area in the scientific literature. It also includes some symbols, their nominations, and explanation of some terms, whenever necessary. This proposal does not intend to be comprehensive or definitive; on the contrary, it intends to be a first step in the process of establishing a standardized nomenclature, serving as a base for a further sound discussion in the scientific community realm.

This article discusses the application of comprehensive two-dimensional gas chromatography (GC x GC) to samples derived from petrochemicals. The use of GC x GC for characterization of petroleum and petroleum derivatives, through group type analysis, such as benzene, toluene, ethylbenzene, xylenes (BTEX), total aromatic hydrocarbons, polyaromatic hydrocarbons, and heteroatomic sulfur-, oxygen-, and nitrogen-containing compounds is presented. The capability of GC x GC to provide additional chemical-specific information regarding petroleum-processing steps, such as linear alkanes dehydrogenation, Fischer-Tropsch process, hydrogenation and oligomerization, is also described. In addition, GC x GC analyses of petrochemical biomarkers and environmental petrochemical-derived pollutants are reported. The role of comparison of samples through use of simple fingerprint approaches is highlighted.

The scope of this study encompasses an overview of the principles of unified chromatography as well as the principles of chromatographic techniques as applied to unified systems, which include gas chromatography, liquid chromatography, supercritical fluid chromatography, high temperature and high pressure liquid chromatography, micro-liquid chromatography, enhanced fluidity chromatography, and solvating gas chromatography. Theoretical considerations and individual instrumental parameters such as mobile phase, sample introduction system, columns, and detection system are also discussed. Future applications of this separation approach are discussed.

An analytical methodology to determine Alachlor, Butralin, and Metolachlor herbicides, and Metalaxyl fungicide, in surface water was developed using Solid Phase Microextraction (SPME) and Gas Chromatography coupled to Mass Spectrometry (GC-MS). The developed method was validated, and the quantification limits were found to be between 0.2 to 1.8 μg.L -1 , depending upon the compound. The precision, as measured by the relative standard deviations (RSD), was in the range 3.5% to 27%. The higher RSD was found for Butralin due to the occurrence of adsorption of this compound in the extraction fiber. After validation the developed methodology was employed to the determination of these four pesticides in water samples that supplies Araraquara and Sao Carlos cities (Sao Paulo - Brazil). Samples from Feijao Creek, Anhumas Creek, Cruzes Creek and Paiol Brook, as well as samples from after-treatment at SAAE (Water and Sewer Supply Service – Sao Carlos, SP, Brazil) and DAAE (Water and Sewer Supply Department – Araraquara, SP, Brazil) were evaluated. Samples from both winter and summer seasons were collected and analysed. The results show that the samples analyzed using the in-house validated methodology were not contaminated with these pesticides within the investigated concentrations.

The identification of compounds by using gas chromatography (GC) in samples with significant complexity comprising a range of isomeric species, where characterization is based on peak retention times and mass spectra, generates uncertainty for the analyst. This leads to identification errors. The most reliable way to confirm the identification of each compound is based on authentic standard co-injection, which in several cases is economically prohibitive, and often unachievable in the time available for analysis. Retention index procedures are important tools to minimize misidentification of compounds in conventional chromatography. The introduction of comprehensive two-dimensional GC (GC × GC) for analysis of complex samples was a decisive step to increase the analytical capacity of chromatographic techniques. For many samples, the chromatographic resolution increase leads to quantitative expansion in the number of peaks identified, compared with conventional GC analysis. Notwithstanding this improved resolution, limitations still persist in correct peak identification, which suggests the use of retention indices may assist in supporting component identification in this important technique. In this work, approaches to use of the retention index in GC × GC are discussed, based on an evaluation of the literature in this area. Interpretation of effective chain length data for fatty acid methyl esters in the first and second dimensions is presented.

The growth of biodiesel market and the implementation of regulations related to biodiesel production and biodiesel/diesel blending has encouraged the development of appropriate analytical methods to control the composition of this type of mixture. In this study, an evaluation of the potential of GC×GC for the characterization of samples of beef tallow biodiesel and the composition of blends of biodiesel/ diesel is presented. The methodology was applied to beef tallow biodiesel and its mixtures with petrodiesel, ranging from B2 to B50. Results allowed not only the identification and quantification of the biodiesel esters, but also the biodiesel percentage in biodiesel/ diesel blends.

In this work, a GCxGC-nitrogen-phosphorus detection (NPD) methodology was developed to separate and quantitate nitrogen-containing compounds in Brazilian heavy gas oil. First, the NPD performance was improved in order to achieve best GCxGC performance. The geometry of this detector was also evaluated. The use of an extended jet improved significantly the peak shape. The GCxGC separation was studied using both first and second dimension columns with different internal diameters. The use of a thicker film in both dimensions provided better performance. LODs of 0.16-8.49 pg of individual compounds were achieved. Two different extraction techniques of the neutral and basic nitrogen-containing compounds were also evaluated. The method using ion-exchange resins to separate neutral and basic nitrogen-containing compounds was more efficient than the method using modified silica. As an example, the amounts (microg/g) of each class reported were: indole (2.77), alkyl carbazoles ranging from C(0) to C(6+) (1.467), alkyl benzocarbazoles from C(0) to C(4+) (793), alkyl quinolines (31.2) and alkyl benzoquinolines (21.6) were quantitated.

The detector is an integral and important part of any chromatographic system. The chromatographic peak profiles (i.e. peak separation) should, ideally, be unaffected by the detector - it should only provide the sensing capacity required at the end of a column separation process. The relatively new technique of comprehensive 2-D GC (GC x GC) extends the performance of GC manyfold, but comes at a price - existing GC systems may not be adequately designed with the requirements of GC x GC in mind. This is primarily the need for precise measurement of very fast peaks entering the detector (e.g. as fast as 50 ms basewidth in some instances). The capacity of the detector to closely track a rapidly changing chromatographic peak profile depends on a number of factors, such as design of flow paths and make-up gas introduction, type of detector response mechanism, and the chemistry of the response. These factors are discussed here as a means to appreciate the technical demands of detection in GC x GC. The MS detector will not be included in this review.

The goal of this article is to discuss the application of comprehensive two-dimensional gas chromatography (GCxGC) to petrochemical samples. The use of GCxGC for petroleum and petroleum derivatives characterization, through group type analysis, or BTEX (benzene, toluene, ethylbenzene, xylenes), total aromatic hydrocarbons, polyaromatic hydrocarbons, sulfur-containing, oxygen-containing, and nitrogen-containing compounds is presented. The capability of GCxGC to provide additional specific chemical information regarding petroleum processing steps, such as dehydrogenation of linear alkanes, the Fischer-Tropsch process, hydrogenation and oligomerization is also described. In addition, GCxGC analyses of petrochemical biomarkers and environmental pollutants derived from petrochemicals are reported.

In this work it was described a simple method for extraction of plasticizer compounds (mainly phthalate esters and bisphenol A (BPA)) from landfill leachate samples. The samples were submitted to an extraction procedures based on precipitation, solid phase extraction (SPE) and ionic exchange chromatography (IEC). Firstly the landfill leachate sample was acidified by addition of HCl concentrated, in order to precipitate the organic compounds that are less soluble in water. The precipitate was washed with several solvents. The aqueous phase was then submitted to SPE with XAD-4™ resin and IEC with Amberlyst A-27™ resin. The instrumental analysis was performed by gas chromatography with mass spectrometer detector (GC/MSD) and the compounds were identified by the GC/MSD library (Wiley) and by using some standard substances. These methodologies allow the isolation and identification of the following compounds: dioctylphthalate, diisobutilphthalate, BPA, benzoic acid, palmitic acid and diisopentylphthalate. The methods are very simple, rapid and selective, for plasticizers extraction from landfill leachate matrices.

A Bacia do Rio Paraíba do Sul engloba uma das regiões mais industrializadas do país. Paralelamente a este desenvolvimento, danos ao meio ambiente estão em condições bem plausíveis de ocorrer, principalmente em relação a questão dos micropoluentes. Quatro métodos analitos, utilizando-se cromatografia liquida acoplada a um espectrômetro de massas, para a quantificação de fármacos e defensivos agrícolas foram validados para a avaliação, através de monitoramento da concentração dos referidos analitos, do panorama da qualidade das águas na região de maior densidade demográfica da bacia, que compreende o Vale do Paraíba paulista e o sul-fluminense. Os analitos contemplados foram fármacos da classe dos analgésicos - cafeína, diclofenaco, ibuprofeno, naproxeno e paracetamol- e defensivos agrícolas utilizados nas culturas mais abundantes da região (arroz, eucalipto e pastagens) que foram: ácido diclorofenoxiacético (2,4-D), atrazina, bentazona, fipronil, imidacloprida e simazina. O monitoramento da concentração foi realizado em onze (11) cidades- Jacareí, São José dos Campos, Caçapava, Taubaté, Pindamonhangaba, Guaratinguetá, Lorena e Lavrinhas - pertencentes ao Estado de São Paulo, e Resende, Volta Redonda e Barra Mansa. A cafeína foi o analito mais detectado (100% das amostras) e que apresentou as maiores concentrações (389 ng.L-1), enquanto para os defensivos agrícolas, o 2,4-D foi o que apresentou maior frequência de detecção (90 %) e a bentazona a maior concentração (75,8 ng.L-1). The Paraíba do Sul River Basin encompasses one of the most industrialized regions of the country. Together with this development, damages to the environment are in very plausible conditions to occur, especially regarding the issue of micropollutants. Four analytical methods, using liquid chromatography coupled to a mass spectrometer, for the quantification of drugs and agricultural pesticides were validated for the evaluation, by monitoring the concentration of chosen analytes, of the panorama of water quality in the region of higher density demography of the basin, which comprises the Vale do Paraiba from São Paulo State and the south of the Rio de Janeiro State. The analyzed analytes were drugs of the analgesic class - caffeine, diclofenac, ibuprofen, naproxen and paracetamol - and agricultural pesticides used in the most abundant crops of the region (rice, eucalyptus and pastures), which were: dichlorophenoxyacetic acid (2,4-D), atrazine, bentazone, fipronil, imidacloprid and simazine. The concentration monitoring was carried out in eleven (11) cities - Jacareí, São José dos Campos, Caçapava, Taubaté, Pindamonhangaba, Guaratinguetá, Lorena and Lavrinhas - belonging to the State of São Paulo, and Resende, Volta Redonda and Barra Mansa. The caffeine was the most detected analyte (was indentified in 100% of the samples) and show the highest concentrations (389 ng.L-1), while for the agricultural pesticides 2,4- D was the one with the highest detection frequency (90%) and the bentazone with the highest concentration (75.8 ng.L-1).