Acetonitrile Extraction Research Articles

Acetonitrile extract of Salvia miltiorrhiza Radix exhibits growth-inhibitory effects on prostate cancer cells through the induction of cell cycle arrest and apoptosis.

In the present study, the effects of the acetonitrile or water extracts from 400 selected traditional medicinal plants on the growth of PC-3 cells were investigated, and it was demonstrated that an acetonitrile extract of Salvia miltiorrhiza Radix exhibited the most marked cytotoxic effects on PC-3 cells. It was observed that the acetonitrile extract of S. miltiorrhiza Radix induced marked cell cycle arrest and apoptosis in PC-3 cells through the generation of intracellular reactive oxygen species. It was also demonstrated that oral administration of the acetonitrile extract of S. miltiorrhiza Radix decreased the incidence and growth of PC-3 tumor xenografts in nude mice. The results of the present study suggest that the acetonitrile extract of S. miltiorrhiza Radix exhibits marked inhibitory effects on the growth of prostate cancer cells in vitro and in vivo.

Evolution of novel sorbents for effective clean-up of honeybee matrix in highly toxic insecticide LC/MS/MS analysis

Highly toxic insecticides (HTIs) belonging to different chemical groups are dangerous to pollinating organisms, even in sublethal doses. An important objective of this study was to develop a method to determine over fifty HTIs at very low concentrations in the bee matrix. The novelty of this research involved obtaining extract completely free from beewaxes, lipids and proteins using EMR-lipid (enhanced matrix removal-lipid), chitin and Z-Sep+ (zirconium oxide and C18 dual-bonded to silica) as clean-up sorbents. Different parameters, such as weight of bees, extraction solvent, and freezing time were evaluated. Determinations were made using liquid chromatography-tandem mass spectrometry (LC-MS/MS). EMR-lipid allows for removing most of the fatty co-extracts and increases the overall performance of the method by reducing the matrix effects (ME) without significant analyte loss. The established modified QuEChERS method based on 1% acetic acid in acetonitrile extraction followed by EMR-lipid clean-up was validated at three different spiking levels (0.001, 0.01 and 0.1mgkg−1). Precision, calculated as relative standard deviation (RSD), was below 20%. The proposed method was used to determine sublethal doses of these insecticides in real samples of dead honeybees.

Determination of 19 sulfonamides residues in pork samples by combining QuEChERS with dispersive liquid-liquid microextraction followed by UHPLC-MS/MS.

A new simple and rapid pretreatment method for simultaneous determination of 19 sulfonamides in pork samples was developed through combining the QuEChERS method with dispersive liquid-liquid microextraction followed by ultra-high performance liquid chromatography with tandem mass spectrometry. The sample preparation involves extraction/partitioning with QuEChERS method followed by dispersive liquid-liquid microextraction using tetrachloroethane as extractive solvent and the acetonitrile extract as dispersive solvent that obtained by QuEChERS. The enriched tetrachloroethane organic phase by dispersive liquid-liquid microextraction was evaporated, reconstituted with 100μL acetonitrile/water (1:9 v/v) and injected into an ultra-high performance liquid chromatography with a mobile phase composed of acetonitrile and 0.1% v/v formic acid under gradient elution and separated using a BHE C18 column. Various parameters affecting the extraction efficiency were investigated. Matrix-matched calibration curves were established. Good linear relationships were obtained for all analytes in a range of 2.0-100μg/kg and the limits of detection were 0.04-0.49μg/kg. Average recoveries at three spiking levels were in the range of 78.3-106.1% with relative standard deviations less than 12.7% (n = 6). The developed method was successfully applied to determine sulfonamide residues in pork samples.

Evaluation of MS2 workflows in LC-Q-Orbitrap for pesticide multi-residue methods in fruits and vegetables.

LC-Q-Orbitrap efficiency was evaluated for pesticide multi-residue analysis by using three workflows involving simultaneous MS and MS2 analysis. They were as follows: data-dependent MS2 (dd-MS2), all-ion fragmentation (AIF) and variable data-independent analysis (vDIA). These MS2 workflows were tested for the main method validation parameters such as detection and identification capabilities, repeatability, linear range and quantitation. QuEChER acetonitrile extracts (blanks and spiked with 166 pesticides) of 11 different fruits and vegetables were used for this evaluation. Blank extracts were analysed to evaluate isobaric compounds and potential false identification. Spiked extracts (at 0.01 and 0.1mgkg-1) were analysed to evaluate the false negatives potentially produced (considering a retention mass window of 0.2min). At 0.01mgkg-1, dd-MS2 had the highest identification rate (96-100%, depending on the matrix). In vDIA, it was 86-100% and in AIF 81-100%. But these two last workflows offered more possibilities for applying screening analysis. It was observed that application of the ion ratio criterion established in the SANTE Guidelines for identification can generate some artificial false negative results. It could be overcome by considering a mass error threshold (i.e. 5ppm) as a selected criterion. Detection and quantitation were carried out in full-scan MS. MS2 data were used for identification. Dd-MS2 provided the highest number of points per chromatographic peak, and by that peak area, repeatability was the best (typically <10%). AIF and vDIA were characterised by longer cycle times; thus, the obtained peak area repeatability was slightly worse, but acceptable (<20%). All workflows showed very good linearity in the range 0.01-0.5mgkg-1. The three MS2 workflows were applied to real samples with good results. Graphical abstract LC-Q-Orbitrap was used for pesticide residues analysis in fruit and vegetables. Three approaches to MS2 identificaton were evaluated.

Employing Central Composite Design for Evaluation of Biomass Production by Fusarium venenatum: In Vivo Antioxidant and Antihyperlipidemic Properties.

The present study deals with the cost effective production of biomass from Fusarium venenatum using different carbon sources (cane sugar, brown sugar, malt and fructose). Optimization of selected carbon sources and seed size using Central Composite Response Surface Design (CCRSD) indicated that sucrose (1.64g/100mL) and seed size (10% v/v) were optimal in maximizing biomass yield (0.5602g/100mL, p<0.0001) and protein yield (49.99%, p<0.01) of Fusarium venenatum. The acetonitrile and methanolic extracts of biomass showed promising antioxidant activity (DPPH assay, 59.7 and 51.9% respectively, 250μg/mL). The mycoprotein, in the Triton-X 100-induced hyperlipidemic model in rats, exhibited significant reduction of serum lipids levels (p<0.01 at 100, 200 and 400mg/kg body weight) with significant increase in HDL level. It also exhibited antibacterial activity against S. aureus. LC-MS analysis of ACN extract of biomass showed two major peaks (Compound 3: m/e 701.4941 and Compound 2: m/e 651.4984). Spectral matching with standard MS libraries indicated that compound 3 may be structurally similar to sterol glycoside (m/e 716.99) with absence of methyl group. Also, compound 2 may be cholest-5-en-3-ol (3β)-, 9-octadecenoate. These results showed that Fusarium venenatum can act as a source of natural antioxidant along with acting as a valuable protein source. It may also prove to be beneficial in treatment of hyperlipidemia and other cardiovascular conditions. Further bioactivity-guided fractionation and isolation will help to obtain bioactives that may serve as leads for design of new class of therapeutic agents.

Analysis of 28 insecticides in curry leaves (Murraya koenigii L.) by gas chromatography and gas chromatography–mass spectrometry

ABSTRACTA simple and efficient method was developed for analysis of 28 insecticides (organochlorines, organophosphates and synthetic pyrethroids) in curry leaves (Murraya koenigii L.). The extraction of the analytes was carried out with acidified acetonitrile and purification with magnesium sulphate, primary secondary amine along with graphitised carbon black to remove excess chlorophyll content in curry leaves. Acetonitrile extracts were changed into hexane + acetone (9 + 1) and hexane + toluene (9 + 1) in the final step. In another method ethyl acetate was used for extraction and purification was carried out as above. The analytes in the samples were determined by gas chromatography (GC) and confirmed by gas chromatography–mass spectrometry (GC–MS). Use of ethyl acetate increased the recovery of the analytes, but co-extractive interference led to higher GC maintenance. Acidified acetonitrile was found to be a better extraction solvent compared with ethyl acetate. The use of hexane:toluene (9:1) as exchange solvent increased the recovery of organochlorine insecticides compared with hexane:acetone (9:1). The limit of quantification (LOQ) of the method was 0.01 mg kg−1 for organochlorine insecticides and 0.05 mg kg−1 for organophosphates and synthetic pyrethroids. The recoveries of organochlorines were within 70.36–82.45%; organophosphates, 82.54–90.93% and synthetic pyrethroids, 88.45–90.71% at the LOQ level. The method developed was found suitable for analysis of real samples of curry leaves. The pesticides detected in curry leaves collected from the retail market were mainly organophosphates and synthetic pyrethroids.

LC-MS/MSによるアユ（&lt;i&gt;Plecoglossus altivelis&lt;/i&gt;）中のフェニコール系薬剤の分析

An analytical method for the determination of residues of 3 phenicol drugs (chloramphenicol, thiamphenicol and florfenicol) in Ayu (Plecoglossus altivelis) by LC-MS/MS was developed. We used the whole body of Ayu, including the bones and internal organs, in addition to muscle. Phenicols were extracted with 90% acetonitrile and an aliquot of the crude extract was cleaned up on a Florisil column (2 g), followed by defatting with n-hexane. The acetonitrile extract was evaporated and the solvent was replaced with phosphate buffer, then the extract was purified on a hydroxylated styrene-divinylbenzene copolymer column (200 mg). Finally, sample solution was passed through a deproteination cartridge filter with a lipid removal function. Chloramphenicol was quantitated by means of a calibration curve corrected with salogate standard (chloramphenicol-d5) and thiamphenicol and florfenicol were quantitated based on absolute calibration curves. This method was validated in accordance with the notification of the Ministry of Health, Labour and Welfare of Japan. As a result of the validation study, the trueness, repeatability and within-laboratory reproducibility were 85-103, 5-13 and 8-13%, respectively. This method is useful for inspecting residues of 3 phenicol drugs in whole body of Ayu efficiently. Moreover, when chloramphenicol and thiamphenicol are detected by this method, the quantitated value is applicable to decide the compliance of the sample with the specifications and standards of the Food Sanitation Law.

Measurement of Superoxide Production and NADPH Oxidase Activity by HPLC Analysis of Dihydroethidium Oxidation.

The fluorogenic probe dihydroethidium (DHE) is widely used for detecting intracellular superoxide. DHE oxidation by superoxide generates specifically the compound 2-hydroxyethidium (2-E+OH), so that 2-E+OH detection confers specificity to superoxide assessment among many other reactive oxygen species. However, DHE oxidation in biological systems leads to formation of other fluorescent products, particularly ethidium, usually formed at higher quantities than 2-E+OH. Since both 2-E+OH and ethidium are fluorescent, their identification and quantification is possible only after their physical separation by HPLC. Here we describe the detailed procedures for superoxide measurement in cells (adhered or not) and fresh tissues fragments, followed by acetonitrile extraction and simultaneous fluorescent detection of 2-E+OH and ethidium and absorbance detection of remaining unreacted DHE. In addition we report the use of DHE/HPLC for measuring NADPH oxidase activity in enriched-membrane fraction isolated from cells or tissues. These methods can improve accuracy and precision of quantitative superoxide measurements in biological samples.

Occurrence of Chlorotriazine herbicides and their transformation products in arable soils

Chlorotriazine herbicides (CTs) are widely used pest control chemicals. In contrast to groundwater contamination, little attention has been given to the circumstances of residue formation of parent compounds and transformation products in soils.Seventy-five cultivated floodplain topsoils in the Czech Republic were sampled in early spring of 2015, corresponding to a minimum of six months (current-use terbuthylazine, TBA) and a up to a decade (banned atrazine, AT and simazine, SIM) after the last herbicide application. Soil residues of parent compounds and nine transformation products were quantified via multiple residue analysis using liquid chromatography - tandem mass spectrometry of acetonitrile partitioning extracts (QuEChERS). Using principal component analysis (PCA), their relation to soil chemistry, crops and environmental parameters was determined.Of the parent compounds, only TBA was present in more than one sample. In contrast, at least one CT transformation product, particularly hydroxylated CTs, was detected in 89% of the sites, or 54% for banned triazines. Deethylated and bi-dealkylated SIM or AT residues were not detectable. PCA suggests the formation and/or retention of CT hydroxy-metabolite residues to be related to low soil pH, and a direct relation between TBA and soil organic carbon, and between deethyl-TBA and clay or Ca contents, respectively, the latter pointing towards distinct sorption mechanisms. The low historic application of simazine contrasted by the high abundance of its residues, and the co-occurrence with AT residues suggests the post-ban application of AT and SIM banned triazines as a permitted impurity of TBA formulations as a recent, secondary source.The present data indicate that topsoils do not contain abundant extractable residues of banned parent chlorotriazines, and are thus likely not the current source for related ground- and surface water contamination. In contrast, topsoils might pose a long-term source of TBA and CT transformation products for ground and surface water contamination.

Antioxidant and antibacterial activities of acetonitrile and hexane extracts of Lentinus tigrinus and Pleurotus djamour

Abstract This paper highlighted the antioxidant and antibacterial activities of Lentinus tigrinus and Pleurotus djamour . Extracts of mushroom fruiting bodies were obtained using hexane and acetonitrile solvents. Acetonitrile extracts of both mushrooms exhibited higher biological activities than hexane extracts. L. tigrinus acetonitrile extract had 39.2% (EC50 value 637.75 mg/L) radical scavenging activity, contained 451 mg AAE (ascorbic acid equivalent)/g sample total phenolics, and showed 9.48 mm diameter zone of inhibition against Staphylococcus aureus . On the other hand, P. djamour acetonitrile extract had 32.8% (EC50 value 762.19 mg/L) scavenging activity, contained 982 mg AAE/g sample total phenolics, and inhibited S. aureus growth with 9.37 mm diameter zone of inhibition. Both hexane extracts did not show any inhibitory effect against the two bacteria used. Collectively, the acetonitrile extracts of L. tigrinus and P. djamour could be valuable resource of antioxidant and anti- S. aureus compounds which we need to isolate, characterize and identify.

Simple and sensitive HPLC-UV method for determination of bexarotene in rat plasma

Bexarotene is currently marketed for treatment of cutaneous T-cell lymphoma and there has been growing interest in its therapeutic effectiveness for other cancers. Neuroprotective effects of bexarotene have also been reported. In this study, a simple, sensitive and cost-efficient bioanalytical method for determination of bexarotene in rat plasma was developed and fully validated. The method utilises protein precipitation with acetonitrile and liquid-liquid extraction with n-hexane-ethyl acetate (10:1, v/v). An HPLC-UV system with a Waters Atlantis C18 column and a mobile phase of acetonitrile-ammonium acetate buffer (10mM, pH 4.1) at a ratio of 75:25 (v/v), flow rate 0.2mL/min was used. Chromatograms were observed by a UV detector with wavelength set to 259nm. Intra- and inter-day validations were performed and sample stability tests were conducted at various conditions. The applicability of the method was demonstrated by a pharmacokinetic study in rats. Intravenous bolus dose of 2.5mg/kg was administered to rats and samples were obtained at predetermined time points. As a result, pharmacokinetic parameters of AUCinf (4668±452hng/mL), C0 (6219±1068ng/mL) and t1/2 (1.15±0.02h) were obtained. In addition, the developed method was further applied to human and mouse plasma to assess the suitability of the method for samples from other species.

Methylamine-modified graphene-based solid phase extraction combined with UPLC-MS/MS for the analysis of neonicotinoid insecticides in sunflower seeds

In this paper, methylamine modified graphene (CH3NH-G) was synthesized and used as solid-phase extraction (SPE) sorbent to cleanup the acetonitrile extract of sunflower seeds for the determination of neonicotinoid insecticides by UPLC-MS/MS. The effects of the type of extraction solvent, pH, the amount of CH3NH-G sorbent as well as the type and volume of eluent on the extraction efficiency were evaluated. Good linearity was obtained for the analytes with coefficient of determination (R2) in the range of 0.9986–0.9998. LOD (S/N=3) and LOQ (S/N=10) were below 6 and 20ngkg−1, respectively. Method recoveries were between 74.3% and 119.1%. Relative standard deviations (RSD) for eight replicate determinations were in the range of 1.7–2.9%. The proposed method has been applied to the analysis of 3 kinds of sunflower seed samples from local market.

Bile Acid Composition Changes over 6 Months Following Fecal Microbiota Transplantation in Children with Recurrent C. difficile Infections: 2016 ACG Presidential Poster Award

Introduction: The mechanism by which Fecal Microbiota Transplant (FMT) cures C. difficile infection (CDI) is incompletely understood. Some studies have suggested that bile acid composition may contribute to FMT effects independent of restored bacterial diversity. We aimed to determine bile acid profiles of pediatric CDI patients before and after FMT as well as from FMT donors. We further compared these results to our previously published 16S rRNA sequencing data from these samples. Methods: Children with a history of recurrent CDI underwent FMT by colonoscopy. Stool was collected from donors, as well as recipients prior to FMT and after FMT at 2-10 weeks, 10-20 weeks and 6 months. After acetonitrile extraction, fecal bile acids were assessed as their methyl ester derivatives by LC-MS using a Simultaneous Ion Monitoring program. The proportions of primary (1°: cholic and chenodeoxycholic) and secondary (2°: deoxycholic and lithocholic) bile acids were determined for each sample, and results were compared using independent t-tests.Figure 1Figure 2Results: All 8 children had resolution of CDI symptoms and eradication of C. difficile 10-20 weeks after FMT, as well as at 6 months for those tested. Before FMT, patients had lower proportions of 2° bile acids compared to donors (31.5% vs 95.0%, p < 0.001), but were restored to donor levels by 6 months (p=0.16). Of the patients, 5 had IBD. Bile acid proportions did not differ by IBD status at baseline. However after 6 months, differences between non-IBD patients and donors persisted for both 1° (23.5% vs 4.7%, p < 0.05) and 2° (74.3% vs 95.0%, p < 0.05) bile acids whereas IBD patients normalized. In comparison to bacterial diversity, bile acid profiles took longer to normalize. Furthermore, whereas bacterial diversity remained restored in non-IBD patients but returned to low baseline values among IBD patients at 6 months, 2° bile acids levels remained normal in IBD patients. Conclusion: Increased 1° bile acids were found in pre-FMT samples, regardless of IBD status. Interestingly, IBD patients exhibited a stronger reversion towards donor bile acid compositions following FMT even though they did not differ from non-IBD patients at baseline. Furthermore, IBD patients had normalized bile acid profiles, even though their gut bacterial diversity returned to pre-FMT values by 6 months. Our results demonstrate that bile acid profiles may change independently of gut bacterial diversity following FMT and may differ by IBD status.

저장기간 중 돌산갓피클에서 Glucosinolates의 ACE 및 α-glucosidase 저해활성

This study was carried out for investigate that physiological activity, quantification and qualitative were sinigrin of Dolsan leaf mustard pickle (DLMP) during storage. sinigrin contains high amounts of nutritional and medicinal compounds, which are important for maintaining optimum health. ACE inhibitory activity was ranged between 43.2 and 79.4%. DLMP methanol extracts demonstrated highest ACE inhibitory activity at 79.4% on day 14, whereas DLMP ethanol extracts demonstrated highest Angiotensin I-converting Enzyme (ACE) inhibitory activity of 43.2% at day 0. The α-glucosidase inhibitory activity of positive control 0.02% (v/v) acarbose was 78%. The DLMP methanol extracts had the highest α-glucosidase inhibitory activity at 64.0% on day 14, whereas DLMP ethanol extracts had the lowest α-glucosidase inhibitory activity of 42.8% at day 28. Sinigrin was high in DLMP methanol extracts at 49.55 μg/ml on day 14 of storage. Sinigrin standard was eluted at 2.73 min and MS analysis was m/z 283.03 along with fragment ions at m/z 204 and 149.06. These data show that sinigrin formed desulfo-glucosinolates [M-SO 3 -2H 2 O+K+2H]+. Sinigrin concentration increased until day 14 and then decreased after that. DLMP methanol extracts had consistently higher sinigrin concentration than DLMP acetonitrile extracts during 28 days of storage.

Antibacterial and hemolytic effects of aqueous and organic extracts from different tissues of sea urchin Echinometra mathaei on pathogenic streptococci

In this study, the antibacterial and hemolytic effects of the gonadal tissue, test, spines and Aristotle’s lantern of the sea urchin (Echinometra mathaei) were investigated. The aerobic Gram-positive pathogenic bacteria Streptococcus mutans and Streptococcus sobrinus were selected because of their importance in oral diseases. The samples of sea urchin were collected from an intertidal zone in the Persian Gulf and then dissected. Finally, the crude extracts of the gonadal tissue, test, spines and Aristotle’s lantern of the samples were separately prepared by the solvents, including phosphate-buffered saline (PBS), 96 % ethanol (Et) and 80 % acetonitrile (ACN). The antibacterial activities of the extracts were evaluated using the well diffusion method in two concentrations of 1500 and 600 µg well−1. The antibacterial effects against streptococcal species were observed in the organic extracts (Et and ACN) of the gonads and test while the extracts of spines and Aristotle’s lantern showed no antibacterial activity. The hemolytic activity of the PBS, 96 % Et, and 80 % ACN extracts from the sea urchin were evaluated using horse red blood cells. Hemolytic activity was observed only in the 80 % Et and ACN extracts of the gonad and test. In conclusion, the organic extracts of gonadal tissue showed the most inhibitory activity on the growth of S. mutans and S. sobrinus.

An effective method for pesticide residues determination in tobacco by GC-MS/MS and UHPLC-MS/MS employing acetonitrile extraction with low-temperature precipitation and d-SPE clean-up

An effective method has been developed and validated for the determination of residues of 55 pesticides in tobacco. The proposed sample preparation method is based on acetonitrile extraction, low-temperature precipitation (LTP) and dispersive solid phase extraction (d-SPE) clean-up. Gas chromatography and ultra-high performance liquid chromatography analysis, both coupled to tandem mass spectrometry (GC-MS/MS and UHPLC-MS/MS), were used for determination. LTP is easy to perform and was crucial to obtain a clean extract. Method quantification limit for the pesticides were between 25 and 75µgkg−1. Extraction recoveries obtained for blank samples spiked at 25, 75, 125 and 250µgkg−1 levels ranged from 63 to 161% with relative standard deviations (RSD)≤20%. The method was successfully applied to the analysis of thirteen different tobacco samples, providing to be a robust procedure for routine analysis. The compounds pirimiphos methyl and isofenphos presented residues in the range of 35–51µgkg−1.

Dissipation dynamics of spirodiclofen in wolfberry fruit

The dissipation of spirodiclofen in fresh fruit and dry fruit of wolfberry was detected in this study to provide a reference for its safe application.According to Pesticide Residue Test Criteria of China, the open-field experiment was conducted in Zhongning courty of Ningxia province, and the dissipation of spirodiclofen was studied by acetonitrile extraction and HPLC-MS/MS detection. The results showed that the half-lives of spirodiclofen in fresh wolfberry fruit and dry wolfberry fruit were 6.9-11.2 days and 8.5-10.4 days, respectively. Spirodiclofen belongs to the easily degradable pesticide type. According to the maximum residue limits (0.5 mg•kg⁻¹) of spirodiclofen of EU for wolfberry, after recommended dosage being sprayed for once, fresh wolfberry fruit was safe to eat after 5 days, and dry wolfberry fruit was safe to eat after 21 days.

Antioxidative, anti-inflammatory potentials and phytochemical profile of Commiphora africana (A. Rich.) Engl. (Burseraceae) and Loeseneriella africana (Willd.) (Celastraceae) stem leaves extracts

ObjectiveTo assess the antioxidant and anti-inflammatory activities as well as to determine the flavonoids and phenolic acids content of active fractions. MethodsTwo medicinal plant samples were extracted successively in Soxhlet apparatus with n-hexane, dichloromethane, acetonitrile, ethyl acetate, methanol and n-butanol. Five methods were used to evaluate the antioxidant activity. Anti-inflammatory activity was done through the inhibition of the cyclooxygenase enzymes (COX-1 and COX-2). Polyphenolic compounds were analyzed by using a spectrophotometrical and high performance liquid chromatography-mass spectrometry (HPLC-MS) methods. ResultsThe data showed that the stem leaves extracts of Commiphora africana and Loeseneriella africana possessed significant in vitro antioxidant and anti-inflammatory activities. Polar extracts had radical scavenging effects and they reduced iron (III). The prostaglandin production was significantly stopped by acetonitrile and methanol extracts. These biological activities were supported by some bioactive compounds quantified by using the HPLC-MS. p-Coumaric acid, ferulic acid, isoquercitrin, quercitrin, quercetin, rutin, kaempferol and apigenin were the most metabolites quantified. ConclusionsThe present study may explain the effectiveness of plants in traditional medicine of Burkina Faso, singularly Commiphora africana and Loeseneriella africana. The next investigation was to sub-fractionate the methanol fraction in order to isolate new antioxidant and/or anti-inflammatory compounds.

Gas chromatography with mass spectrometry for the quantification of ethylene glycol ethers in different household cleaning products

A rapid and simple procedure is reported for the determination of six ethylene glycol ethers in cleaning products and detergents using gas chromatography with mass spectrometry. The analytes were extracted from 2.0 g samples in acetonitrile (3 mL) and the extract was submitted to a clean-up step by QuEChERS method, using a mixture containing 0.3 g magnesium sulfate, 0.15 g primary/secondary amine, and 0.05 g C18 . The clean acetonitrile extract (1 μL) was injected into the chromatographic system. No matrix effect was observed, so the quantification of the samples was carried out against external standards. Detection limits were in the range 3.0-27 ng/g for the six ethylene glycol ethers. The recoveries obtained, using the optimized procedure, were in the 89.4-118% range, with relative standard deviations lower than 14%. Twenty-three different household cleaning products, including glass cleaner, degreaser, floor, softeners, and clothes and dishwashing detergents, were analyzed. Large interindividual variations were observed between samples and compounds.

Determination of Triazole Fungicide Residues in Fruits by QuEChERS Combined with Ionic Liquid-Based Dispersive Liquid-Liquid Microextraction: Optimization Using Response Surface Methodology

A rapid, efficient, and environmentally friendly method using quick, easy, cheap, effective, rugged, and safe (QuEChERS) combined with ionic liquid-based dispersive liquid-liquid microextraction (QuEChERS-IL-DLLME) prior to high-performance liquid chromatography coupled with photodiode array detection (HPLC-PDA) has been developed for the determination of six triazole fungicides (triazolone, triadimenol, epoxiconazole, flusilazole, tebuconazole, and diniconazole) in various fruits (pear, apple, and grapefruit). Several parameters affecting the extraction efficiency in IL-DLLME, such as type and volume of ionic liquid and acetonitrile volumes and extraction time, were investigated by single factor experiments. Then, the extractant volume, dispersant volume, and extraction time were optimized using response surface methodology (RSM). The optimal values were determined to be within an extractant volume of 63.7 μL, a dispersant volume of 0.43 mL, and an extraction time of 1.7 min, respectively. Under the optimum conditions, an excellent linearity with determination coefficient higher than 0.997 was obtained. The average recoveries in three concentration levels (0.2, 0.5, and 1 mg kg−1) ranged from 63.8 to 119.1 %, respectively, and the relative standard deviations (RSDs) from 1.1 to 12.6 %. The limits of detection (LODs) (S/N = 3) and limits of quantification (LOQs) (S/N = 10) for the six triazole fungicides ranged from 3.4 to 26.8 μg kg−1 and 9.8 to 50.3 μg kg−1, respectively. The proposed method was successfully applied for the determination of trace amounts of triazole fungicides in various fruits including pear, apple, and grapefruit.