A fast, sensitive, and selective direct injection electrospray tandem mass spectrometry (DI ESI MS/MS) method that is able to quantify ethyl carbamate in commercial sweetened sugar cane spirit is described. The preparation method uses a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) with potassium carbonate added to sweetened sugar cane spirit to separate the aqueous phase from the ethanol phase. The aqueous phase contains sucrose that suppresses electrospray ionization. Ethyl carbamate supernatant from the ethanol phase is transferred and enriched with 18-crown-6/trifluoroacetic acid additives. The additives sequester metal cations reducing the ionization of sodium and potassium, favoring the detection of ethyl carbamate as sole protonated cations. The method was successfully applied for the quantification of eleven real samples and certified sugar cane spirit demonstrating its applicability for quality control and regulatory analysis. The method showed reliable analytical parameters compared to conventional gas chromatography mass spectrometry (GC-MS) method commonly used for ethyl carbamate analysis. DI-ESI-MS/MS method requires just a fast step sample clean up and presents consistent values for the limit of detection (LOD 48.0 μg L-1) and limit of quantification (LOQ 160.0 μg L-1). Furthermore, the recoveries obtained were close to 100%, with relative standard deviations below 10% of sample certificates.

Vegetable oil analyses, especially due to the complexity of the oil components, are commonly laborious, requiring several analytical techniques. In this work, electrospray ionization mass spectrometry with direct injection (DIMS), along with 18-crown-6 ether (crown ether) chelating agent and trifluoroacetic acid (TFA), was used to characterize and semi-quantitatively evaluate commercial vegetable oils. As a result, an unprecedented DIMS method of triacylglycerols (TAGs) analysis for semi-quantitative profiling of fatty acids in commercial oils (e.g., soybean, sunflower, corn, oil, canola), without sample derivatization, was developed. The results of the ion abundances related to the analyzed TAGs, with quantitative percentage analyzed by gas chromatography with flame ionization detector (GC-FID), allowed generating correction factors for each oil. DIMS analysis with crown ether/TFA resulted in the elimination of isobaric interferences from sodium and potassium adducts, facilitating the ion assignments, due to the one-ion-per-molecule observation in the mass spectrum. Chemometric analyses by principal component analysis (PCA) and heatmap, to evaluate the ionic profile of the oils, grouped them accordingly to their TAG content. Olive oil was identified as the most different from the other oils. Overall, a semi-quantitative approach to investigate the vegetable oils, reaching low percentage variation for DIMS, with 2 min analyses and 30 min sample preparation, was proposed.

Fusarium oxysporum is usually found in foods such as corn, wheat, soybeans and barley, and can cause economic losses and risks to health in humans and animals due to the production of mycotoxins. The conventional microbiological test for fungal identification is based on morphological characteristics, requires specialists, and it is very time-consuming as it is necessary to carry out a culture of the fungus for two weeks before microorganism identification. Nowadays, researchers have made efforts to develop alternative analytical methods with advantages such as shorter time of analysis and better accuracy and reproducibility when compared to microbiological methods. In this way, in the present work, a qualitative analytical method to detect the secondary metabolites of Fusarium oxysporum in culture media by gas chromatography coupled to mass spectrometry (GC-MS) was developed with the intention of relating the presence of these chemical compounds to contamination by the fungus. The method comprised liquid-liquid or liquid-solid extractions with ethyl acetate from liquid and solid culture media, respectively, followed by GC-MS analysis, which was able to identify the presence of fusaric acid, 13-socosenamide, 5-(4-hydroxybutyl)-2-pyridinecarboxylic acid and toxin HT-2. The presence of these compounds was confirmed by high-performance liquid chromatography coupled to mass spectrometry quadrupole time of flight (HPLC-MS/QTOF).

O objetivo do presente trabalho foi avaliar os efeitos do óleo de linhaça sobre as concentrações dos teores de ácidos graxos poli-insaturados n-6 e n-3 (AGPI) em cabeças de tilápia do Nilo (Oreochromis niloticus), um resíduo do pescado normalmente descartado durante o processo de filetagem. A quantificação dos ácidos graxos poli-insaturados foi realizada utilizando-se cromatografia gasosa (CG), sendo a concentração dos ácidos graxos expressa em termos de massa absoluta através da utilização do éster metílico (23:0) como padrão interno e do TCFx (fator de correção teórica do FID). As tilápias receberam dietas com níveis crescentes de óleo de linhaça (0,00, 1,25, 2,50, 3,75 e 5,00%) em substituição ao óleo de girassol (controle) durante um período de cinco meses. A ingestão de LNA causa a dessaturação sequencial e alongamento das cadeias carbônicas de ácidos graxos presentes nas cabeças de peixes, levando a um aumento em todos os AGPIs n-3. Este experimento demonstrou claramente que a adição de óleo de linhaça na ração de tilápia do Nilo aumenta significativamente as concentrações (em 100 g-1 de cabeça) de LNA (100,8 para 973,6 mg), EPA (4,8 para 82,1 mg) e DHA (24,0 para 125,4 mg). Estas alterações contribuem acentuadamente para melhorar a razão AGPI n-6/n-3 e, desta forma, pode ser utilizada em suplementos alimentícios, transformando as cabeças de tilápia em valiosa alternativa como fonte de alimento para dieta humana.

The objective of this study was to examine the effects of linseed oil on n-6 and n-3 polyunsaturated (PUFA) fatty acid content in the heads of Nile tilapia (Oreochromis niloticus), these are normally discarded during the filleting process. The quantification of PUFA was carried out in absolute weights through the use of methyl ester (23:0), as an internal standard, and TCFx (theoretical FID correction factor) by GC gas chromatography. Tilapias were given diets with increasing levels (0.00, 1.25, 2.50, 3.75 and 5.00%) of linseed oil as a replacement for sunflower oil (control) for a period of five months. The ingestion of LNA causes sequential desaturation and elongation in fish heads, leading to an increase in all n-3 PUFAs. This experiment demonstrated clearly that adding linseed oil to the feed of Nile tilapia can markedly increase the amounts (per 100 g-1 of head) of LNA (100.8 to 973.6 mg), EPA (4.8 to 82.1 mg), and DHA (24.0 to 125.4 mg) in their heads, and thus, may be used to help balance n-6/n-3 PUFA ratios in dietary supplements, and creating a valuable alternative food source in the human diet.

Foi desenvolvido um método de extração limpo, assistido por microondas, para a determinação de herbicidas triazínicos em amostras de solos. A estratégia de extração foi baseada em ambiente micelar associado às microondas, seguido da determinação dos herbicidas por CLAE, de tal forma que o procedimento pudesse ser considerado limpo. Foram utilizadas duas porções (10 e 8 mL) da solução extratora de SDS (dodecil sulfato de sódio) 0,06% (m/v) associada a 0,500 g da amostra e da seguinte programação do forno de microondas: 540 W (6 min), 0 W (1 min), 630 W (2 min). As curvas analíticas apresentaram-se lineares na faixa de 0.05 até 10.0 mg L-1 para atrazina, ametrina e simazina. Os limites de detecção e quantificação foram estimados como 0,90, 0,57 e 0,235 µg g-1 e 3,1, 1,9 e 0,8 µg g-1 para atrazina, ametrina e simazina, respectivamente. O método proposto é preciso (RSD < 8%, n = 3) e os resultados obtidos concordam com aqueles do método clássico. Testes de recuperação dos herbicidas para amostras de solo forneceram valores entre 82,0 e 94,0%.

It was developed a green microwave-assisted extraction method for determination of triazine herbicides in soil samples. The extraction strategy was based on micellar medium associated to microwaves followed by the herbicides determination by HPLC in such way that the procedure could be considered as green. Two portions (10 and 8 mL) of aqueous SDS (sodium dodecyl sulphate) 0.06% (m/v) were used as extracting solutions associated to 0.500 g of sample and the following microwave oven program: 540 W (6 min), 0 W (1 min), 630 W (2 min). The analytical curves were linear in the analytical range of 0.05 up to 10.0 mg L-1 for atrazine, ametryne and simazine. The limits of detection and quantification were estimated as 0.90, 0.57 and 0.235 µg g-1 and 3.1, 1.9 and 0.8 µg g-1 for atrazine, ametryne and simazine, respectively. The proposed method is precise (RSD < 8%, n = 3) and the obtained results are in agreement with the classical one. Recovery tests for soil samples indicated that the percentage of recuperation were between 82.0 e 94.0%.

Foram comparados os resultados de determinações quantitativas de ésteres metilícos de ácidos graxos de óleos vegetais (soja, linhaça e dendê) entre oito métodos de esterificação com catálises ácidas e básicas. Os métodos selecionados foram descritos por Metcalfe, 1966 (MET, ref. 17); Bannon, 1982 (BAN, ref. 18); Joseph e Ackman, 1992 (JAC, ref. 3); Hartman e Lago, 1973 (HLA, ref. 19); Jham, 1982 (JHA, ref. 20); ISO 5509, 1978 (ISO, ref. 21); Bannon, 1982 (BBA, ref. 15) e Schuchardt e Lopes, 1988 (SLO, ref. 22). Apesar da grande variação apresentada para o teor de ácidos graxos insaturados, todos os métodos foram eficientes para os ácidos graxos saturados. Os resultados obtidos mostram que a determinação de ácidos graxos pode ser afetada pela composição do óleo e que os métodos JAC, ISO e BBA são os mais eficientes. Os métodos ISO e BBA por apresentarem baixa toxidez e baixo custo são os recomendados para amostras que apresentem baixa acidez. O método JAC deve somente ser recomendado para amostras com alta acidez porque os métodos ISO e BBA são realizados em meio básico e podem não determinar os ácidos graxos livres.

The results of the quantitative determination of fatty acid methyl esters of vegetable oils, (soybean, flaxseed, and palm oils) by eight basic and acid catalysis esterification methods were compared. The selected methods were described by Metcalfe, 1966 (MET, ref. 17); Bannon, 1982 (BAN, ref. 18); Joseph and Ackman, 1992 (JAC, ref. 3); Hartman and Lago, 1973 (HLA, ref. 19); Jham, 1982 (JHA, ref. 20); ISO 5509, 1978 (ISO, ref. 21); Bannon, 1982 (BBA, ref. 15) and Schuchardt and Lopes, 1988 (SLO, ref. 22). Despite the large variation in the determination of unsaturated fatty acids, all the methods were efficient in the analysis of saturated fatty acids. The results obtained show that fatty acid analysis may be affected by oil composition and that JAC, ISO, and BBA methods are more efficient. ISO, and BBA are recommended for low acidity samples due to their low reagent toxicity and cost. The JAC method is recommended only for high acidity samples, as the ISO and BBA methods are carried out in basic medium and cannot analyze the free fatty acids.

The aim of this report is to classify analytical methods based on flowing media and to define (standardize) terminology. After the classification and a discussion of terms describing the systems and component parts, a section is devoted to terms describing the performance of flow systems. The list of terms included is restricted to the most relevant ones; especially "self-explanatory" terms are left out. It is emphasised that the usage of terms or expressions that do not adequately describe the processes or procedures involved should be strongly discouraged. Although belonging to the category of methods based on flowing media, chromatographic methods are not comprised in the present document. However, care has been taken that the present text is not in conflict with definitions in that domain. In documents in which flow methods are described, it should be clearly indicated how the sample and/or reagent is introduced and how the sample zone is transported. When introducing new techniques in the field, or variants of existing techniques, it is strongly recommended that descriptive terms rather than trivial or elaborate names are used.