The methodology developed in this study through the acquisition of fingerprint chromatograms by liquid chromatography-diode array detector (LC-DAD), aided by principal component analysis, made it possible to assess, in a rational way, the chemical differences between six accessions of Lippia alba and to verify the influence of the method of extraction, the seasonality and the individuality of each accession on chemical composition of its extracts. Among all extracts analyzed against cancer cell lines, eight of them showed to be more promising against a human leukemia cell line (HL-60), displaying cell growth inhibition percentage ranging between 40.0 and 52.0%. In the inhibitory activity assays against acetylcholinesterase enzyme, all extracts showed weak inhibitory effect, with highlight only for six of them, which displayed inhibition ranging between 27.0 and 32.0%.

An extraction method based on solid-phase extraction was developed to determine the major alkaloid components, N,N-dimethyltryptamine, harmine, harmaline, harmalol, and tetrahydroharmine, in ayahuasca using ultra-performance liquid chromatography-tandem mass spectrometry. Coconut charcoal and menthone-thiosemicarbazone polymer were tested as new adsorbent materials. Experiments carried out at levels of 1, 5, 10, 50, 100, and 250 µg mL-1 resulted in recoveries in the ranges 45.3-115.7% for menthone-thiosemicarbazone and 40.6-116.2% for coconut charcoal. The detection and quantification limits ranged from 0.003 to 0.016 µg mL-1 and from 0.009 to 0.043 µg mL-1, respectively. The method developed was linear over the tested range (0.05-1.0 µg mL-1), with correlation coefficients ranging from 0.9969 to 0.9998. The technique was applied for analysis of the compounds in an ayahuasca sample collected from a religious group located in the city of Fortaleza, obtaining concentrations in the range from 0.3 to 19.3 mg mL-1.

This work describes the removal of pesticides from water using activated and magnetized biochars produced from exhausted husk, and dry tannin from barks of black wattle (Acacia mearnsii De Wild.). These materials were characterized using chemical, spectroscopic, thermal, solid structure and surface area techniques. The activated and magnetized biochars were effective in removing the pesticides thiacloprid and thiamethoxam from both ultrapure water and Marcela Water Reservoir, Itabaiana, Sergipe State, Brazil. At the longest time examined, the amounts of thiacloprid and thiamethoxam adsorbed per gram of activated biochar adsorbent were 1.02 and 0.97 mg, respectively, while values of 0.73 mg (thiacloprid) and 0.40 mg (thiamethoxam) were obtained using magnetized biochar. A pseudo-second order model correctly described the kinetics of adsorption of both pesticides (R(2) ≥ 0.922). Desorption experiments revealed that the spent biochars could not be easily regenerated, which indicated that the forces holding the adsorbed fluid molecules to the solid surface were relatively strong.

Um método baseado na técnica de dispersão da matriz em fase sólida foi desenvolvido para determinar resíduos de ametrina, tetraconazol, flumetralina, tebuconazol, pirimetanil, diclofuanida e cresoxim-metílico na planta medicinal desidratada Hyptis pectinata (sambacaitá) por cromatografia a gás acoplada a espectrometria de massas. Diferentes parâmetros foram avaliados, tais como: tipo (C18, alumina neutra, sílica gel e Florisil) e quantidades de sorvente e solvente de eluição (diclorometano, acetato de etila e diclorometano:acetato de etila (1:1, v/v)), sendo que o mais adequado foi o procedimento com 0,5 g de planta medicinal, 0,5 g de C18 como sorvente e diclorometano (20 mL) como solvente de eluição. O método foi validado com amostras de planta medicinal fortificadas com agrotóxicos em diferentes níveis de concentração (0,05-1,0 µg g-1). Recuperações médias (n = 4) variaram de 83 a 127%, com coeficientes de variação entre 4 e 15%. Os limites de detecção (LOD) variaram entre 0,02 e 0,07 µg g-1, enquanto que os limites de quantificação (LOQ), entre 0,05 e 0,1 µg g-1.

A method was developed using matrix solid-phase dispersion (MSPD), together with gas chromatography coupled to mass spectrometry (GC-MS) for determination of ametryn, tetraconazole, flumetralin, tebuconazole, pyrimethanil, dichlofluanid and kresoxim-methyl in dehydrated Hyptis pectinata (sambacaitá) medicinal plant material. The evaluated parameters included the type and amount of sorbent (C18, neutral alumina, silica gel and Florisil) and the nature of the eluent (dichloromethane, ethyl acetate and dichloromethane:ethyl acetate (1:1, v/v)). The best results were obtained using 0.5 g of plant material, 0.5 g of C18 as sorbent and dichloromethane (20 mL) as the eluting solvent. The method was validated using plant samples spiked with pesticides at different concentration levels (0.05-1.0 µg g-1). Average recoveries (using four replicates) ranged from 83 to 127%, with relative standard deviations between 4 and 15%. Limits of detection (LOD) and quantification (LOQ) were in the ranges 0.02-0.07 µg g-1 and 0.05-0.1 µg g-1, respectively.

A turfa natural foi testada na extração em fase sólida de acefato, clorprofam, pirimicarbe, bifentrina, tetradifona e fosalona da planta medicinal Cordia salicifolia, utilizando cromatografia a gás acoplada a espectrometria de massas no modo de monitoramento de íons selecionados. Considerando que a legislação brasileira não estabelece limites máximos de resíduos para plantas medicinais, a recuperação foi avaliada em dois níveis de concentração (0,5 e 1,0 mg kg-1), resultando em valores de recuperação entre 64% e 118%, com coeficientes de variação entre 5,6% e 26,4% para a turfa. Os limites de detecção variaram entre 0,10 e 0,15 mg kg-1, enquanto que os limites de quantificação, entre 0,15 e 0,25 mg kg-1 para os pesticidas estudados. O método desenvolvido foi linear no intervalo de 0,1 a 5,0 μg g-1, com coeficientes de correlação entre 0,9975 e 0,9986. A comparação entre a turfa natural e o sorbente convencional (alumina neutra) apresentou desempenho similar da turfa na recuperação dos seis pesticidas.

Natural peat was tested for solid-phase extraction of acephate, chlorpropham, pirimicarb, bifenthrin, tetradifon and phosalone from the medicinal plant Cordia salicifolia, using gas chromatography-mass spectrometry with selected ion monitoring (GC/MS, SIM). Considering that there are no Brazilian regulations concerning maximum permissible pesticide residue concentrations in medicinal herbs, recovery experiments were carried out (three replicates) at two arbitrary fortification levels (0.5 and 1.0 mg kg-1), resulting in recoveries ranging from 64% to 118% and relative standard deviations between 5.6% and 26.4% for peat sorbent. Detection and quantification limits for herb ranged from 0.10 to 0.15 mg kg-1 and from 0.15 to 0.25 mg kg-1, respectively, for the different pesticides studied. The developed method was linear over the range assayed, 0.1-5.0 μg g-1, with correlation coefficients ranging from 0.9975 to 0.9986 for all pesticides. Comparison between natural peat and conventional sorbent (neutral alumina) showed similar performance of peat for the six pesticides tested.

A method based on matrix solid-phase dispersion and gas chromatography-mass spectrometry to determine procymidone, malathion, bifenthrin and pirimicarb in honey is described. The best results were obtained using 1.0 g of honey, 1.0 g of silica-gel as dispersant sorbent and acetonitrile as eluting solvent. The method was validated by fortified honey samples at three concentration levels (0.2, 0.5 to 1.0 mg kg-1). Average recoveries (n=7) ranged from 54 to 84%, with relative standard deviations between 3.7 and 8.5%. Detection and quantification limits attained by the developed method ranged from 0.02 to 0.08 mg kg-1 and 0.07 to 0.25 mg kg-1 for the honey, respectively.

Foi desenvolvido um estudo sobre a presença dos herbicidas simazina, metribuzim, metolacloro, trifluralina, atrazina e seus metabólitos desisopropilatrazina (DIA) e desetilatrazina (DEA) em água superficial e subterrânea da região de Primavera do Leste, Mato Grosso, Brasil. O procedimento analítico baseou-se na extração em fase sólida com cartuchos descartáveis Sep-Pak C18 e eluição com acetato de etila. Os níveis de resíduos foram determinados por cromatografia a gás com detector de nitrogênio e fósforo. Para a maior parte dos pesticidas, a recuperação média nos diferentes níveis de fortificação foi >70% com estimativa do desvio padrão relativo <19%. As recuperações observadas para o DIA e a trifluralina foram 25% e 56%, respectivamente. As baixas recuperações foram atribuídas à retenção incompleta do DIA e à forte retenção no sorvente e alta volatilidade da trifluralina. Os limites de detecção variaram de 0,023 a 0,088 µg L-1. Este método foi aplicado na análise de 5 amostras de águas superficiais e 28 de águas subterrâneas, em pontos usados para abastecimento de água para consumo humano, coletadas em Primavera do Leste, Mato Grosso. O nível mais elevado encontrado nas amostras de água foi 1,732 µg L-1 de metolacloro enquanto o herbicida encontrado com maior freqüência foi o metribuzim.

A study on the presence of herbicides, namely simazine, metribuzin, metolachlor, trifluralin, atrazine and two metabolites, deisopropylatrazine (DIA) and deethylatrazine (DEA), was performed in ground and surface waters from Primavera do Leste region, Mato Grosso state (Middle West of Brazil). The analytical procedure was based on solid-phase extraction (SPE) with Sep-Pak C18 disposable cartridges and ethyl acetate for elution solvent. Residue levels were determined by gas chromatography with nitrogen-phosphorus detection. For most of the pesticides average recoveries at different fortification levels were >70% with relative standard deviation <19%. The recoveries of DIA and trifluralin in water were 25% and 56%, respectively, which were attributed to the incomplete retention of DIA and strong retention on the sorbing material and high volatility of trifluralin. Detection limits ranged from 0.023 to 0.088 µg L-1. This method was applied for the analysis of 5 superficial water samples and 28 groundwater samples, in places used for human consumption without previous treatment, collected in Primavera do Leste, Mato Grosso, Brazil. Results indicated that the highest level of contamination in a water sample was 1.732 µg L-1 for metolachlor, while metribuzin was the most frequently detected herbicide with maximum concentration of 0.351 µg L-1.

Um método simples e eficiente baseado na técnica de dispersão da matriz em fase sólida foi desenvolvido para determinar resíduos de dimetoato, parationa-metílica, malationa, tebuconazol, e cipermetrina em tomate, por cromatografia gasosa acoplada a espectrometria de massas no modo de monitoramento de íons selecionados. Diferentes parâmetros foram avaliados, tais como: tipo (C18, alumina, sílica-gel e Florisil) e quantidade de sorbente e solvente de eluição (diclorometano, acetato de etila, n-hexano e n-hexano:acetato de etila (1:1 e 1:3, v/v)), sendo que o mais adequado foi alumina na proporção matriz:sorbente de 4:1 (m/m), Florisil como sorbente de purificação e diclorometano como solvente de eluição. Recuperações médias (n=7) de tomates fortificados (0,05-4,0 mg kg-1) variaram de 77 a 100%, com coeficiente de variação entre 3,7% e 12,9%. Os limites de detecção variaram entre 0,01 e 0,02 mg kg-1, enquanto que os limites de quantificação variaram entre 0,03 e 0,06 mg kg-1. O método foi aplicado em amostras de tomates coletadas na cidade de Aracaju, SE, sendo que resíduos de parationa-metílica, malationa e dimetoato foram detectados, porém abaixo dos limites máximos de resíduos (LMRs) estabelecidos pela legislação brasileira e pelo Codex Alimentarius.

A simple and effective extraction method based on matrix solid-phase dispersion was developed to determine dimethoate, methyl-parathion, malathion, tebuconazole and cypermethrin in tomato using gas chromatography-mass spectrometry and selected ion monitoring (GC-MS, SIM). Different parameters of the method were evaluated, such as type of solid phase (C18, alumina, sílica-gel and Florisil), the amount of solid phase and eluent [dichloromethane, ethyl acetate, n-hexane and n-hexane:ethyl acetate (1:1 and 1:3, v/v)]. The best results were obtained using 2.0 g of tomato, 0.5 g of alumina as dispersant sorbent, 0.5 g of Florisil as clean-up sorbent and dichloromethane as eluting solvent. The method was validated by fortified tomato samples at different concentration levels (0.05 to 4.0 mg kg-1). Average recoveries (7 replicates) ranged from 77% to 100% with relative standard deviation between 3.7% and 12.9%. Detection and quantification limits ranged from 0.01 to 0.02 mg kg-1 and 0.03 to 0.06 mg kg-1 for the whole fruit of tomato, respectively. The proposed method was applied to analyze of these compounds in commercial tomato samples and residues of methyl-parathion, dimethoate and malathion were detected on the tomato samples at concentrations below the maximum residue levels (MRLs) established by Brazilian legislation and Codex Alimentarius.

Um método alternativo, utilizando cromatografia líquida com detecção espectrofotométrica, para análise de procloraz como o produto de degradação 2,4,6-triclorofenol em manga, mamão e laranja é descrito. Acetato de etila, acetona e diclorometano foram testados para a extração de procloraz das frutas. Após a extração, procloraz foi submetido a uma reação com cloridrato de piridina para gerar o derivado 2,4,6-triclorofenol. A análise foi realizada por cromatografia líquida com detector espectrofotométrico e por cromatografia gasosa com detecção por captura de elétrons. Recuperações médias de frutas fortificadas (0,1 e 0,2 mg kg-1) variaram de 80 a 94% com coeficiente de variação entre 5,6% e 12,6% (n=8). Os limites de detecção e quantificação foram 0,05 e 0,1 mg kg-1, respectivamente. O método alternativo foi aplicado a amostras de manga e mamão, as quais foram tratadas por imersão em solução da formulação de procloraz sob condições de laboratório. Além disso, amostras de frutas de mercados locais foram analisadas.

An alternative method using liquid chromatography with UV detection for the determination of prochloraz as 2,4,6-trichlorophenol in mango, papaya and orange is described. Ethyl acetate, acetone and dichloromethane were tested for extraction of prochloraz from the fruits. After extraction the residue of prochloraz was derivatized with pyridine hydrochloride. The analysis was carried out using liquid chromatography with UV detection and gas chromatography with electron-capture detection. Average recoveries of prochloraz from spiked fruits (0.1 and 0.2 mg kg-1) ranged from 80% to 94% with relative standard deviations between 5.6% and 12.6% (n=8). Detection and quantification limits were 0.05 and 0.1 mg kg-1, respectively. The LC-UV method was applied to mango and papaya samples submitted to dip treatment with a prochloraz formulation under laboratory conditions. In addition, fruit samples obtained from local markets were analysed.

A rapid and sensitive method is described for the determination of clofentezine residues in apple, papaya, mango and orange. The procedure is based on the extraction of the sample with a hexane:ethyl acetate mixture (1:1, v/v) and liquid chromatographic analysis using UV detection. Mean recoveries from 4 replicates of fortified fruit samples ranged from 81% to 96%, with coefficients of variation from 8.9% to 12.5%. The detection and quantification limits of the method were of 0.05 and 0.1 mg kg-1, respectively.

Um método rápido e eficiente é descrito para a análise de resíduos de tiabendazol e imazalil em limão (casca e polpa). O procedimento é baseado numa extração com hexano:acetato de etila (1:1, v/v) e análise por cromatografia a gás com detector termiônico específico. A possibilidade do efeito de matriz foi investigada. Os valores de recuperação média de 8 análises de amostras de limão fortificadas variaram de 79% a 109%, com valores de desvio padrão relativo entre 2,4% e 12,8%. Os limites de detecção e de quantificação do método foram 0,2 mg kg-1 e 0,5 mg kg-1, respectivamente.

A rapid and efficient method is described for the determination of thiabendazole and imazalil residues in lemons (peel and pulp). The procedure is based on the extraction with an hexane:ethyl acetate mixture (1:1, v/v) and gas chromatographic analysis using thermionic specific detection (TSD). The possibility of matrix effect was also studied. Mean recoveries from 8 replicates of fortified samples ranged from 79% to 109%, with relative standard deviation values between 2.4% to 12.8%. The detection and quantification limits of the method were 0.2 mg kg-1 and 0.5 mg kg-1, respectively.

Herbicidas tais como trifluralina, simazina, atrazina, metribuzina e metolaclor são usados na agricultura brasileira. A eficiência de um método em pequena escala para a determinação destes herbicidas e dois produtos de degradação em amostras de solo foi avaliada. Os compostos foram extraídos das amostras de solo (5 g) com 20 ml de acetato de etila em agitador mecânico por 50 min. Após a extração, o sobrenadante foi filtrado em sulfato de sódio anidro, concentrado e analisado por cromatografia a gás de alta resolução com detector termiônico específico. Valores médios de recuperação obtidos de amostras de solo fortificadas em três níveis diferentes variaram de 81 a 115 % com valores de desvio padrão relativo entre 1,2 e 12,7 %. Os limites de detecção do método variaram de 0,01 a 0,06 mg kg-1. A metodologia foi aplicada a amostras de solo de fazendas localizadas próximas à cidade de Araraquara, estado de São Paulo, Brasil.

Herbicides such as trifluralin, simazine, atrazine, metribuzin and metolachlor are used in Brazilian agriculture. The efficiency of a small scale method for determination of these herbicides and two degradation products (deisopropylatrazine and deethylatrazine) in soil samples was evaluated. The compounds were extracted from soil samples (5 g) with 20 ml of ethyl acetate in a mechanical shaker for 50 min. Following the extraction, the supernatant was dried through anhydrous sodium sulphate, concentrated and analysed by high resolution gas chromatography (HRGC) with thermionic specific detection (TSD). Mean recoveries obtained from soil samples fortified at three different levels ranged from 81 to 115% with relative standard deviation (RSD) values varying from 1.2 to 12.7%. The method detection limits ranged from 0.01 to 0.06 mg kg-1. The methodology was applied using soil samples from farms located near the town of Araraquara, in the State of São Paulo, Brazil.