Métodos para análises de HPA e BTEX em águas subterrâneas de postos de revenda de combustíveis: um estudo de caso em Campo Grande, MS, Brasil

Two methods using headspace solid-phase microextraction and gas chromatography - mass spectrometry were developed for the determination of polycyclic aromatic hydrocarbons (PAH) and BTEX. Best results were obtained using DVB/CAR/PDMS fiber, with 10 min extraction at 25 °C and 0.15 min desorption at 260 °C (BTEX), and PDMS/DVB fiber, with 60 min extraction at 90 °C, 10% NaCl and 5 min desorption at 270 °C (PAH). LOD intervals were 3x10-2 - 5x10-2 µg L-1 (BTEX) and 1.6x10-3 - 1.4 µg L-1 (PAH). The methods were applied to forty-five groundwater samples from monitoring wells of gas stations and only benzene level exceeded the limit established by Brazilian regulations.

Straightforward synthesis of 2,2,4,4,5,7,7-d7-cholestane: a new deuterated standard in petroleum analysis

A short and efficient synthesis of heptadeuterated 2,2,4,4,5,7,7-d7-cholestane (1) from cholesterol (3) is described. The deuterated material will be useful for the analysis of different sources of petroleum in analytical geochemistry laboratories as internal standard for quantification of steranes via gas chromatography-mass spectrometry (GC-MS).

VOLATILE COMPONENTS FROM GALLS INDUCED BY Baccharopelma dracunculifoliae(Hemiptera: Psyllidae) ON LEAVES OF Baccharis dracunculifolia(Asteraceae)

The volatile components of the galls induced by the insect Baccharopelma dracunculifoliae (Hemiptera: Psyllidae) on leaves of Baccharis dracunculifolia (Asteraceae) were analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatographyflame- ionisation detection (GC-FID), and then comparison with volatile oil samples from healthy leaves collected in the vicinity. The galls produced around 3.5% of the total organic volatiles whereas healthy leaves rendered an average yield of 0.6%. The observed higher proportions of germacrene D, bicyclogermacrene, limonene, and β-pinene in the galls suggest that all these compounds are important targets in the search for natural enemies of this Psyllid. Moreover, higher relative percentages of (E)-nerolidol and spathulenol were found in healthy leaves.

EVALUATION OF A BUFFERED SOLID PHASE DISPERSION PROCEDURE ADAPTED FOR PESTICIDE ANALYSES IN THE SOIL MATRIX

An evaluation of the pesticides extracted from the soil matrix was conducted using a citrate-buffered solid phase dispersion sample preparation method (QuEChERS). The identification and quantitation of pesticide compounds was performed using gas chromatography-mass spectrometry. Because of the occurrence of the matrix effect in 87% of the analyzed pesticides, the quantification was performed using matrix-matched calibration. The method's quantification limits were between 0.01 and 0.5 mg kg-1. Repeatability and intermediate precision, expressed as a relative standard deviation percentage, were less than 20%. The recoveries in general ranged between 62% and 99%, with a relative standard deviation < 20%. All the responses were linear, with a correlation coefficient (r) ≥0.99.

COMPARAÇÃO DE MÉTODOS POR CROMATOGRAFIA LÍQUIDA NA DETERMINAÇÃO DE MULTIRRESÍDUOS DE AGROTÓXICOS EM MORANGOS

Liquid chromatography is often used for the determination of pesticide multiresidues in foods. In Brazil, the strawberry crop is an example of a food with high levels of irregularities because of the application of pesticides. This is a major concern from the perspective of food safety, environmental protection, and certification for food export. The purpose of this study is to evaluate and compare chromatographic separation and detection methods in relation to a newly developed and validated method using ultra high performance liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS) for the analytical determination of pesticides in strawberries. The comparisons were based on evaluations of the analysis time, consumption of the solvent in the mobile phase, injection volume, detectability, matrix effect, and recovery. The results showed that the LC–MS/MS and UHPLC–MS/MS techniques were both extremely efficient at analyzing pesticide residues with different physico-chemical parameters that were present at low concentrations in a complex matrix. The UHPLC separation method provided better chromatographic performance and productivity, which contributed favorably to routine analytical determinations. Detection by MS/MS had better detectability and selectivity compared with the diode array detector.

CONSTITUENTS OF ESSENTIAL OIL AND HYDROLATE OF LEAVES OF Campomanesia viatoris LANDRUM

The chemical composition of the essential oil and hydrolates of Campomanesia viatoris Landrum were investigated by gas chromatography/mass spectrometry (GC/MS) and a GC flame ionization detector (GC-FID). The major constituents were tasmanone (70.50, essential oil; 74.73%, hydrolate), flavesone (12.77, essential oil; 12.24%, hydrolate) and agglomerone (6.79, essential oil; 10.84%, hydrolate). Tasmonone was isolated and its structure was characterized by spectrometric analysis, specifically 1D and 2D nuclear magnetic resonance (NMR) and mass spectrometry (MS). These findings supports the quimiotaxonomic relationship with Campomanesia and Eucalyptus genera.

2-(4-IODO-2,5-DIMETOXIFENIL)-N-[(2-METOXIFENIL)METIL]ETAMINA OU 25I-NBOME: CARACTERIZAÇÃO QUÍMICA DE UMA DESIGNER DRUG

Drug trafficking and the introduction of new drugs onto the illicit market are one of the main challenges of the forensic community. In this study, the chemical profile of a new designer drug, 2-(4-iodine-2,5-dimethoxyphenyl)-n-[(2-methoxyphenyl)methyl]etamine or 25I-NBOMe was explored using thin layer chromatography (TLC), ultraviolet-visible spectrophotometry (UV-Vis), attenuated total reflection with Fourier transform infrared spectroscopy(ATR-FTIR), gas chromatography mass spectrometry (GC-MS) and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS). First, the TLC technique was effective for identifying spots related to 25C-, 25B- and 25I-NBOMe compounds, all with the same retention factor, Rf ≈ 0.50. No spot was detected for 2,5-dimethoxy-4-bromoamphetamine, 2,5-Dimethoxy-4-chloroamphetamine or lysergic acid diethylamide compounds. ATR-FTIR preserved the physical-chemical properties of the material, whereas GC-MS and ESI-MS showed better analytical selectivity. ESI(+)FT-ICR MS was used to identify the exact mass (m/z428.1706 for the [M + H]+ ion), molecular formula (M = C18H22INO3), degree of unsaturation (DBE = 8) and the chemical structure (from collision induced dissociation, CID, experiments) of the 25I-NBOMe compound. Furthermore, the ATR-FTIR and CID results suggested the presence of isomers, where a second structure is proposed as an isomer of the 25I-NBOMe molecule.

Hentriacontane: a leaf hydrocarbon from Syzygium jambos with stimulatory effects on the germination of urediniospores of Puccinia psidii

A crude Sohxlet extract from leaves of Syzygium jambos was sequentially fractionated using a silica gel flash column. A bioassay based on the numbers of urediniospores of Puccinia psidii that germinated in 2% water agar detected an active stimulant of germination when the fraction eluted with 100% n-hexane was used. The active fraction induced up to 88% increase in germination when added to a spore suspension in mineral oil. The active fraction was characterized as a hydrocarbon by ¹H nuclear magnetic resonance, 13C nuclear magnetic resonance, and infrared analysis. Gas chromatography-mass spectrometry analysis indicated that the fraction was a long-chain 436 MW hydrocarbon with corresponding to C31H64, namely hentriacontane. This is the first time such a compound proved to be involved with stimulation of fungal spore germination. These results may contribute to better understanding the infection process of rusts.

Chemical composition, acetylcholinesterase inhibitory and antifungal activities of Pera glabrata (Schott) Baill. (Euphorbiaceae)

Pera glabrata (Schott) Baill. was selected for this study after showing a preliminary positive result in a screening of Atlantic Forest plant species in the search for acetylcholinesterase inhibitors and antifungal compounds. The bioassays were conducted with crude ethanol extract of the leaves using direct bioautography method for acetylcholinesterase and antifungal activities. This extract was partitioned with hexane, chloroform and ethyl acetate solvents. The active chloroform fraction was submitted to silica gel chromatography column affording 12 groups. Caffeine, an alkaloid, which showed detection limits of 0.1 and 1.0 µg for anticholinesterasic and antifungal activities, respectively, was isolated from group nine. After microplate analyses, only groups four, nine, 10, 11 and 12 showed acetylcholinesterase inhibitory activity of 40% or higher. The group 12 was purified by preparative layer chromatography affording four sub-fractions. Two sub-fractions from this group were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. The first sub-fraction showed anticholinesterasic activity and contained two major compounds: 9-hydroxy-4-megastigmen-3-one (84%) and caffeine (6%). The second sub-fraction presented five major compounds identified as 9-hydroxy-4-megastigmen-3-one, isololiolide, (-) loliolide, palmitic acid and lupeol and did not show activity.

Cytotoxicity of Marchantia convoluta leaf extracts to human liver and lung cancer cells

The cytotoxicity of three extracts (petroleum ether, ethyl acetate and n-butanol) from a plant used in folk medicine, Marchantia convoluta, to human non-small cell lung carcinoma (H1299) and liver carcinoma (HepG2) cell lines was tested. After 72-h incubation of lung and liver cancer cell cultures with varying concentrations of extracts (15 to 200 µg/mL), cytotoxicity was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and reported in terms of cell viability. The extracts that showed a significant cytotoxicity were subjected to gas chromatography-mass spectrometry analysis to identify the components. The ethyl acetate, but not the petroleum ether or n-butanol extract, had a significant cytotoxicity against lung and liver carcinoma cells with IC50 values of 100 and 30 µg/mL, respectively. A high concentration of ethyl acetate extract (100 µg/mL) rapidly reduced the number of H1299 cells. At lower concentrations of ethyl acetate extract (15, 30, and 40 µg/mL), the numbers of HepG2 cells started to decrease markedly. Gas chromatography-mass spectrometry analysis of the ethyl acetate extract revealed the presence of several compounds such as phytol (23.42%), 1,2,4-tripropylbenzene (13.09%), 9-cedranone (12.75%), ledene oxide (7.22%), caryophyllene (1.82%), and caryophyllene oxide (1.15%). HPLC analysis result showed that there were no flavonoids in ethyl acetate extract, but flavonoids are abundant in n-butanol extract. Further studies are needed regarding the identification, toxicity, and mechanism of action of active compounds.

Efficacy of geraniol but not of β-ionone or their combination for the chemoprevention of rat colon carcinogenesis

β-ionone (βI), a cyclic isoprenoid, and geraniol (GO), an acyclic monoterpene, represent a promising class of dietary chemopreventive agents against cancer, whose combination could result in synergistic anticarcinogenic effects. The chemopreventive activities of βI and GO were evaluated individually or in combination during colon carcinogenesis induced by dimethylhydrazine in 48 3-week-old male Wistar rats (12 per group) weighing 40-50 g. Animals were treated for 9 consecutive weeks with βI (16 mg/100 g body weight), GO (25 mg/100 g body weight), βI combined with GO or corn oil (control). Number of total aberrant crypt foci (ACF) and of ACF ≥4 crypts in the distal colon was significantly lower in the GO group (66 ± 13 and 9 ± 2, respectively) compared to control (102 ± 9 and 17 ± 3) and without differences in the βI (91 ± 11 and 14 ± 3) and βI+GO groups (96 ± 5 and 19 ± 2). Apoptosis level, identified by classical apoptosis morphological criteria, in the distal colon was significantly higher in the GO group (1.64 ± 0.06 apoptotic cells/mm²) compared to control (0.91 ± 0.07 apoptotic cells/mm²). The GO group presented a 0.7-fold reduction in Bcl-2 protein expression (Western blot) compared to control. Colonic mucosa concentrations of βI and GO (gas chromatography/mass spectrometry) were higher in the βI and GO groups, respectively, compared to the control and βI+GO groups. Therefore, GO, but not βI, represents a potential chemopreventive agent in colon carcinogenesis. Surprisingly, the combination of isoprenoids does not represent an efficient chemopreventive strategy.

Effect of (+)-dehydrofukinone on GABAA receptors and stress response in fish model

(+)-Dehydrofukinone (DHF) is a major component of the essential oil of Nectandra grandiflora (Lauraceae), and exerts a depressant effect on the central nervous system of fish. However, the neuronal mechanism underlying DHF action remains unknown. This study aimed to investigate the action of DHF on GABAA receptors using a silver catfish (Rhamdia quelen) model. Additionally, we investigated the effect of DHF exposure on stress-induced cortisol modulation. Chemical identification was performed using gas chromatography-mass spectrometry and purity was evaluated using gas chromatography with a flame ionization detector. To an aquarium, we applied between 2.5 and 50 mg/L DHF diluted in ethanol, in combination with 42.7 mg/L diazepam. DHF within the range of 10-20 mg/L acted collaboratively in combination with diazepam, but the sedative action of DHF was reversed by 3 mg/L flumazenil. Additionally, fish exposed for 24 h to 2.5-20 mg/L DHF showed no side effects and there was sustained sedation during the first 12 h of drug exposure with 10-20 mg/L DHF. DHF pretreatment did not increase plasma cortisol levels in fish subjected to a stress protocol. Moreover, the stress-induced cortisol peak was absent following pretreatment with 20 mg/L DHF. DHF proved to be a relatively safe sedative or anesthetic, which interacts with GABAergic and cortisol pathways in fish.

Comparison of volatile and polyphenolic compounds in Brazilian green propolis and its botanical origin Baccharis dracunculifolia

Ethanolic extracts and essential oils from Green Propolis from southeastern Brazil and leaf buds from its botanical origin Baccharis dracunculifolia were analyzed by Reversed Phase High Performance Liquid Chromatography (RP-HPLC), Reversed Phase High Performance Thin Layer Chromatography (RP-HPTLC) and Gas Chromatography - Mass Spectrometry (GC-MS). The essential oils were obtained by hydro-distillation. Both ethanolic extracts and essential oils showed similar chromatographic profiles. Thirteen flavonoids were identified by RP-HPLC and RP-HPTLC analyses in both samples. Twenty-three volatile compounds were identified by GC-MS analyses. Seventeen were present in both essential oils. The major flavonoid compound in both extracts was artepillin C. The major volatile compound in both essential oils was nerolidol. The major compounds identified in this work could be used as chemical markers in order to classify and identify botanical origins of propolis.

Stability of volatile profile and sensory properties of passion fruit juice during storage in glass bottles

This study aimed at assessing the stability of passion fruit juice in glass bottles during a 120-day storage period, regarding its volatile compounds profile and sensory properties (aroma and flavor). Samples were obtained from a Brazilian tropical juice industry (Fortaleza, Brazil) and submitted to sensory and chromatographic analyses. The characteristic aroma and flavor of passion fruit were evaluated by a trained panel with a non-structured scale of 9 cm. The headspace volatile compounds were isolated from the product by suction and trapped in Porapak Q, analyzed through high-resolution gas chromatography and identified through gas chromatography-mass spectrometry (GC-MS). Twelve odoriferous compounds were monitored: ethyl butanoate, ethyl propanoate, 3-methyl-1-butanol, 3-methyl-2-butenol, (E)-3-hexenol, (Z)-3-hexenol, 3-methylbutyl acetate, benzaldehyde, ethyl hexanoate, hexyl acetate, limonene and furfural. The slight variations observed in the volatile profile were not enough to provoke significant changes in the characteristic aroma and flavor of the passion fruit juice.

Volatile compounds from organic and conventional passion fruit (Passiflora edulis F. Flavicarpa) pulp

The volatile compositions from organic and conventional passion fruit pulps produced in Brazil were investigated. The pulps were also physicochemically characterized. The volatile compounds from the headspace of the passion fruit pulp were stripped to a Porapak Q trap for 2 hours; they were eluted with 300 µL of dichloromethane, separated by gas chromatography/flame ionisation detection and identified through gas chromatography/mass spectrometry. Both pulps conformed to the requirements of the Brazilian legislation, indicating they were suitable to be industrialized and consumed. A total of 77 compounds were detected in the headspace of the passion fruit pulps - 60 of which were identified, comprising 91% of the total chromatogram area. The major compounds were the following: ethyl butanoate, 52% and 57% of the total relative area of the chromatogram for the organic and conventional passion fruit pulps, respectively; ethyl hexanoate, 22% and 9%, respectively; and hexyl butanoate, 2% and 5%, respectively. The aroma of the organic passion fruit pulp is mainly related to the following volatile compounds: ethyl hexanoate, methyl hexanoate, β-myrcene and D-limonene. The conventional passion fruit pulp presented methyl butanoate, butyl acetate, hexanal, 1-butanol, butyl butanoate, trans-3-hexenyl acetate, cis-3-hexen-1-ol, butyl hexanoate, hexyl butanoate, 3-hexenyl butanoate and 3-hexenyl hexanoate as the main volatile compounds for aroma.