Abstract
An analytical method coupling pressurized liquid extraction (PLE), pre-concentration by thermal desorption (ATD) and analysis by GC/MSMS was developed for the quantification of pesticides in ...air and dust near vineyards crops to evaluate potential exposure of residents living near these crops. PLE was done using acetonitrile and extracts were concentrated under fume hood to 1 mL. 100 μL of the extract was spiked in a Tenax TA tube and internal standards and N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide were added before thermal desorption at 300°C for 30 min. GC/MSMS analysis was done in MRM mode and limits of quantification and limits of detection were determined for each matrix (passive air sample, active air sample and dust). The method was applied in the field and shows good sensitivity and accuracy.
Dust is the repository of various compounds including flame retardants. In this study an analytical method based on PLE extraction and gas chromatography–mass spectrometry was selected for the ...analysis of 16 PBDEs congeners in house and car dust samples collected in Portugal. The analytical performance of the method was validated using standard reference material (SRM); values from 90% to 109% and from 2% to 11% were obtained for recovery and precision, respectively. The PBDE congeners distribution in whole and sieved fractions of the dust samples, as well as influence of the source on the levels of these contaminants, were obtained. The wide range of PBDEs contents found in the dust samples indicates heterogeneous levels of contamination in these matrices. The clearest feature of the results obtained was that Deca-BDE was the main PBDE in both house and car dust samples. The total PBDEs measured in house dust (ranging from 34 to 1928
ng
g
−1) was lower than those found in car dust (ranging from 193 to 22
955
ng
g
−1). However, house dust provides a major contribution to human exposure due to the time spent there, much higher than in cars.
•PLE technique was applied to alga collected in Galicia (Spain).•The FA identification and quantification was performed by GC–MS.•The applied PLE method allowed to enrich USFA from L. ochroleuca ...alga.•New technology to obtain high quality FAs and phenols from L. ochroleuca is provided.
The increase of pathologies like cardiovascular diseases, obesity or diabetes due to the nature of diet is a matter of concern in our society. Because of this, there is a high interest in healthy natural products that could prevent the appearance of such diseases. This paper aims to study the content of fatty acids (FAs) and phenolic compounds of brown alga Laminaria ochroleuca (L. ochroleuca) and to determine the nutritional quality of the lipids extracted using pressurized liquids extraction (PLE) technique. PLE was applied to the algae using four solvents of different polarity (hexane, ethyl acetate, ethanol and ethanol:water 1:1). Results showed that the higher yield (52%), is obtained with ethanol: water solvent, however, both ethyl acetate and ethanol enrich unsaturated fatty acid (USFA) (palmitoleic, linolenic, linoleic, oleic, araquidonic and eicosapenataenoic) in the lipid fraction of L. ochroleuca, providing extracts up to 55% of their total fatty acid content compared to other solvents. The nutritional quality of the lipids in all PLE extracts was assessed by considering the ω-6/ ω-3 fatty acid ratio and two dietary indexes involved in the risks of coronary heart disease, atherogenic (AI) and thrombogenic (TI). The lower (best) index values are for ethanol extract, 4.4 (ω-6/ ω-3), 0.74 (AI) and 1.05 (TI), followed of ethyl acetate, 4.4 (ω-6/ ω-3), 0.87 (AI) and 1.24 (TI). Finally, the antioxidant capacity of PLE alga extracts in terms of total phenol content (TPC) was analyzed by the Folin-Ciocalteu method. The ethanol: water extracts showed the highest TPC with a concentration up to 173.65 mg eq. gallic acid / g PLE extract.
Marine organisms are potentially prolific sources of high qualify fatty acids that represent useful leads in the development of new nutraceutical agents. In this work, we investigated the lipid ...composition of six algae species from the Northwest of Spain (
,
,
and
) and compared the antioxidant and antibacterial activity of ethanolic extracts obtained by pressurized liquid extraction (PLE). Furthermore,
(
PLE using five solvents of different polarities (hexane, ethyl acetate, acetone, ethanol and ethanol:water 50:50) at three temperatures (80 °C, 120 °C and 160 °C) was investigated.
ethanolic PLE extract presents considerably higher capacity of inhibiting 50% of DPPH (1,1-diphenyl-2-picryl hydrazyl) (IC
= 7.17 μg/mL) in comparison with the rest of macroalgae studied. Moreover, the potential antimicrobial activity tested on
and
shows that
extract produced the best inhibition (IC
was 2.24 mg/mL (
) and 1.27 mg/mL
)). Furthermore, regarding the different solvents and temperatures used to investigate
PLE, results showed that this technique using ethyl acetate is a selective method to enrich long chain fatty acids (oleic acid, arachidonic acid and eicosapentaenoic acid) with ω-6/ω-3 ratios close to 2.7.
We describe a pressurized liquid extraction (PLE) method, followed by gas chromatography-mass spectrometry, for the determination of polybrominated diphenyl ethers (PBDEs) in soil samples. Different ...extraction solvents (isohexane, dichloromethane, acetone and methanol), either alone or in combination, were used to extract these target compounds from spiked soil samples. Variables affecting the PLE extraction efficiency, such as pressure, temperature, number of extraction cycles and static extraction time were studied; the optimum parameters were 1,500 psi, 100 °C, 1 cycle and 5 min, respectively. Purification of crude extracts from the PLE system was achieved by adsorption chromatography using different proportions of acid silica and activated silica; the most effective mixture being either 10 g acid modified silica : 5 g silica or 15 g acid modified silica : 0 g silica. The PLE based method was compared with more traditional Soxhlet and ultrasonic extraction methods; overall the mean percentage recoveries using PLE were 95 ± 9%, and compared favourably with the Soxhlet 94 ± 4% and were better than the ultrasonic method 108 ± 36%. The limits of detection and quantification of the proposed method were 11-54 and 38-180 pg g⁻¹, respectively, for the different PBDE studied. The developed method was linear over the range from 0.05 to 30 ng g⁻¹ except for PBDE 183 of 0.10-30 ng g⁻¹. The established method was successfully applied to soil samples from Scotland, UK, for the determination of the target PBDEs.
•MOSH and MOAH determination in dry food using PLE followed by on-line LC–GC.•PLE for selective extraction of superficial contamination (mainly from packaging).•PLE method for determining total ...contamination.•Method performances and comparison with classical solvent extraction.•Applications to pasta and rice samples.
Pressurised liquid extraction (PLE) represents a powerful technique which can be conveniently used for rapid extraction of mineral oil saturated (MOSH) and aromatic hydrocarbons (MOAH) from dry foods with a low fat content, such as semolina pasta, rice, and other cereals. Two different PLE methods, one for rapid determination of superficial contamination mainly from the packaging, the other for efficient extraction of total contamination from different sources, have been developed and optimised. The two methods presented good performance characteristics in terms of repeatability (relative standard deviation lower than 5%) and recoveries (higher than 95%). To show their potentiality, the two methods have been applied in combination on semolina pasta and rice packaged in direct contact with recycled cardboard. In the case of semolina pasta it was possible to discriminate between superficial contamination coming from the packaging, and pre-existing contamination (firmly enclosed into the matrix).
Analytical methods have been developed that allow for the determination of antiphlogistics, lipid regulators, the antiepileptic carbamazepine, cytostatic agents, the psychiatric drug diazepam and ...iodinated contrast media (ICM) as well as two major polycyclic musk fragrances HHCB (galaxolide) and AHTN (tonalide) in activated and digested sludge. The procedures consist of ultrasonic solvent extraction (USE) using methanol/acetone or pressurized liquid extraction (PLE) using 100% methanol. Clean-up was performed with C
18ec material and silica gel followed by LC tandem MS (electrospray or atmospheric pressure chemical ionization) detection for pharmaceuticals and iodinated contrast media as well as GC/MS in the SIM mode for musk fragrances. Absolute recoveries from spiked activated sludge in general ranged from 88
±
4 to 119
±
20% for ICM and were 78
±
15 and 87
±
10% for the AHTN and HHCB, respectively. For the pharmaceuticals, absolute recoveries in activated sludge ranged between 43 and 78%. Subsequently, compensation of losses was carried out by using surrogate standards (acidic pharmaceuticals: fenoprop, neutral pharmaceuticals: dihydro-carbamazepine, musk fragrances: AHTN-D
3). With one exception the recoveries were also adequate in digested sludge ranging from 43% to 120%.
The objective of this study was to develop a novel analytical chemistry method, comprised of a coupled high-performance liquid chromatography–gas chromatography/mass spectrometry system (LC–GC/MS) ...with low detection limits and high selectivity, for the identification and determination of oxygenated polycyclic aromatic hydrocarbons (OPAHs) and polycyclic aromatic hydrocarbons (PAHs) in urban air and diesel particulate matter. The linear range of the four OPAHs, which include 9,10-anthraquinone, 4
H
-cyclopentadefphenanthrene-4-one, benzanthrone, and 7,12-benzaanthraquinone, was 0.7 pg–43.3 ng with limits of detection (LODs) and limits of quantification (LOQs) on the order of 0.2–0.8 and 0.7–1.3 pg, respectively. The LODs in this study are generally lower than values reported in the literature, which can be explained by using large-volume injection. The recoveries of the OPAHs spiked onto glass fiber filters using two different pressurized liquid extraction (PLE) methods were in the ranges of 84–107 and 67–110 %, respectively. The analytical protocols were validated using the following National Institute of Standards and Technology standard reference materials: SRM 1649a (Urban Dust), SRM 1650b (Diesel Particulate Matter), and SRM 2975 (Diesel Particulate Matter, Industrial Forklift). The measured mass fractions of the OPAHs in the standard reference materials (SRMs) in this present study are higher than the values from the literature, except for benzanthrone in SRM 1649a (Urban Dust). In addition to the OPAHs, 44 PAHs could be detected and quantified from the same particulate extract used in this protocol. Using data from the literature and applying a two-sided
t
test at the 5 % level using Bonferroni correction, significant differences were found between the tested PLE methods for individual PAHs. However, the measured mass fractions of the PAHs were comparable, similar to, or higher than those previously reported in the literature.
Extraction conditions for the determination of tributyltin (TBT) in sediment samples have been developed further. The analytical procedure is based on spiking with isotopically labelled analyte, ...pressurised liquid extraction (PLE) with a hexane/tropolone mixture, Grignard derivatization and quantification by GC-MS. It was applied to two unknown sediment samples as part of an intercomparison exercise of the Comité Consultatif pour la Quantité de Matière (CCQM). The detection limit was approximately 1.5 ng/g TBT as Sn, while the repeatability and intermediate precision (as the coefficient of variation) were 1.9% and 3.2%, respectively. The expanded uncertainty was 6.2% (coverage factor k = 2), and the accuracy was confirmed by measurement of a certified reference material.
A rapid, sensitive, and reproducible method was developed for quantitative determination of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and its biodegradation intermediates, ...hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX) in soils. RDX, MNX, DNX, or TNX was extracted from soil by pressurized liquid extraction (PLE), followed by cleanup using florisil. Instrumental analysis was performed using gas chromatography with electron capture detection (GC–ECD), which was highly sensitive to the parent explosive and its metabolites. The method detection limits (MDLs) were 0.243, 0.095, 0.138, and 0.057
ng/g for RDX, MNX, DNX, and TNX, respectively. The method gave high recovery (98–102%), good precision (0.22–5.14%), and reproducibility, and proved to be suitable for real world sample analysis.
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