Performance Liquid Chromatography-electrospray Ionization-mass Spectrometry Research Articles

PM10 Organic Aerosol Fingerprints by Using Liquid Chromatography Orbitrap Mass Spectrometry: Urban vs. Suburban in an Eastern Mediterranean Medium-Sized Coastal City

This study compares the PM10 (particulate matter of diameter smaller than 10 μm) organic aerosol composition between urban and suburban stations in Heraklion, Crete, during winter 2024 in order to highlight the impact of local anthropogenic activities on urban atmospheric particulate matter pollution. Using an HPLC-ESI-MS Orbitrap analyzer (High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry) in full MS scan mode at a resolution of 140,000, 48 daily aerosol filter extracts were analyzed in both positive and negative modes, resulting in the detection of 2809 and 3823 features, respectively. Features with at least five times higher intensity in the urban environment compared to the suburban, and p < 0.05, were deemed significant. A correlation with black carbon (r > 0.6) was observed for 71% of significant urban features in positive mode. These features showed a predominance of low O:C ratios (<0.2) and the majority were classified as intermediate volatility organic compounds (IVOCs), indicating fresh primary emissions. A clear urban–suburban distinction was shown by PCA of positive mode features, unlike the negative mode features. Regarding the total intensity of the features, urban samples were on average 55% higher than suburban samples in positive mode and 39% higher in negative mode. This study reveals the molecular profile of locally emitted combustion related organics observed in positive mode in an urban environment.

Bacterial responses to plant antimicrobials: the case of alkannin and shikonin derivatives.

Alkannin, shikonin and their derivatives (A/S) are secondary metabolites produced in the roots of certain plants of the Boraginaceae family such as Lithospermum erythrorhizon Siebold & Zucc. and Alkanna tinctoria (L.) Tausch. These naphthoquinones express anti-cancer, wound healing, and antimicrobial activities. To study the interactions between endophytic bacteria isolated from A. tinctoria and the antimicrobials A/S, endophytic bacteria known to be resistant to the compounds were screened for their effect on A/S in liquid medium. Thereafter, the strain Pseudomonas sp. R-72008, was selected and tested for its ability to modify A/S in nutrient medium and minimal medium with A/S as sole carbon source. Bacterial growth was recorded, and high performance liquid chromatography-diode array and ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry analyses were performed to detect and quantify metabolites. In nutrient medium inoculated with R-72008, a decrease in the amount of A/S monomers initially present was observed and correlated with an increase of A/S oligomers. Moreover, a significant decrease of initial A/S monomers in minimal medium was correlated with bacterial growth, showing for the first time that a bacterial strain, Pseudomonas sp. R-72008, was able to use the naphthoquinones A/S as sole carbon source. This study opens new perspectives on the interactions between bacteria and plant antimicrobials.

Bioactive compounds of parsley (Petroselinum crispum), chives (Allium schoenoprasum L) and their mixture (Brazilian cheiro-verde) as promising antioxidant and anti-cholesterol oxidation agents in a food system

This study determined the bioactive composition and antioxidant potential of parsley, chives and their mixture (Brazilian cheiro-verde). Additionally, the effect of these herbs against cholesterol oxidation in grilled sardines (Sardinella brasiliensis) was also investigated. Ultra-high Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (UHPLC-ESI-MS) analyses revealed the presence of phenolic acids (caffeic, chlorogenic, and ferulic acids) and flavonoids (apigenin, kaempferol, catechin) in the herbs. Higher levels of phenolics (2.10 ± 0.02 mg GAE/g) and carotenoids (205.95 ± 0.17 µg/g) were determined in parsley extracts. Moreover, parsley also presented higher antioxidant capacity by DPPH (59.21 ± 0.07 %) and ORAC (109.94 ± 18.7 µM TE/g) than the other herbs. In vivo analyses demonstrated that the herbs’ extracts decreased the damage on Saccharomyces cerevisiae cells exposed to H2O2, except the chives extract at 10 μg/mL. Higher levels of cholesterol oxidation products (COPs) were determined after grilling. The total COPs increased from 61.8 ± 0.7 (raw fish) to 139.7 ± 10.1 µg/g (control). However, the addition of herbs effectively reduced cholesterol oxides formation, this effect was more pronounced in fish containing 4% parsley and 4% cheiro-verde. Promising results were found for cheiro-verde; however, it did not present synergic antioxidant effects.

Is selenium beneficial or detrimental to earthworm? Growth and metabolism responses of Eisenia Fetida to Na2SeO3 exposure

Se unevenly distributed in soils due to variations of geology and anthropogenic input, which results in different effects on earthworms. The effects of Se were characterized by analyzing the growth and metabolism responses of earthworms after exposure to three different concentrations of Na2SeO3. The results showed that except the possible growth promotion at 5 mg/kg, low and middle-level exposure to Na2SeO3 (0.3–10 mg/kg) did not significantly affect the growth of earthworms. While a significant inhibition effect on growth was observed in the high-level exposure group (30–70 mg/kg). There was an inflection point for Se performing promotion to inhibition effects on earthworm growth. To investigate the metabolic response of earthworms, a novel HPLC-ESI-MS (High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry) method was used to determine sensitive biomarkers. Selenium exposure significantly altered the metabolism of seven essential amino acids, namely tyrosine, leucine, phenylalanine, valine, alanine, glycine, and lysine, and two selenoamino acids, namely selenomethionine and methylselenocysteine. The overall metabolism level of earthworms was not affected at low exposure concentrations, but was affected at medium and high exposure concentrations. The metabolic pathways that integrated the selenocompound metabolism and the tricarboxylic acid cycle from the perspective of energy supply and demand were affected by Na2SeO3 exposure. The derived reactive oxygen species at high exposure concentrations were probably the reason for the growth inhibition effect of Se on earthworms. This study provides biochemical insights into the effects of Na2SeO3 on earthworms and suggests that an Se concentration of about 2.3 mg/kg is appropriate for soil organism health.

Secondary metabolic profiles and anticancer actions from fruit extracts of immature pomegranates.

Immature fruits from Punica granatum L. thinning are a neglected side product of pomegranate production with cumbersome disposal costs for farmers. To explore value potential of immature fruits from pomegranate ‘Wonderful’ cultivars, the compositional landscapes and antitumorigenic activities of pomegranate extracts from two different stages of maturation were assessed. Cancer cell proliferation and cytotoxicity was quantified in human lung H1299 and colon HCT116 adenocarcinomas by crystal violet staining, MTS assay and caspase-3 activity. High performance liquid chromatography—diode array detector (HPLC/DAD) and high performance liquid chromatography—electrospray ionization—mass spectrometry (HPLC/ESI-MS) analyses indicate that immature fruits are rich sources of gallotannins and ellagitannins, with the highest amounts contained in immature fruit peels. Biological investigations reveal a robust anticancer activity by those immature P. granatum fruit extracts, which reflected induction of tumor cytotoxicity and cell death mechanisms. Together, present observations suggest P. granatum byproducts from the thinning process may provide unexplored values for virtuous circular economy.

Taxifolin stability: In silico prediction and in vitro degradation with HPLC-UV/UPLC–ESI-MS monitoring

Taxifolin has a plethora of therapeutic activities and is currently isolated from the stem bark of the tree Larix gmelinni (Dahurian larch). It is a flavonoid of high commercial interest for its use in supplements or in antioxidant-rich functional foods. However, its poor stability and low bioavailability hinder the use of flavonoid in nutritional or pharmaceutical formulations. In this work, taxifolin isolated from the seeds of Mimusops balata, was evaluated by in silico stability prediction studies and in vitro forced degradation studies (acid and alkaline hydrolysis, oxidation, visible/UV radiation, dry/humid heating) monitored by high performance liquid chromatography with ultraviolet detection (HPLC-UV) and ultrahigh performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS). The in silico stability prediction studies indicated the most susceptible regions in the molecule to nucleophilic and electrophilic attacks, as well as the sites susceptible to oxidation. The in vitro forced degradation tests were in agreement with the in silico stability prediction, indicating that taxifolin is extremely unstable (class 1) under alkaline hydrolysis. In addition, taxifolin thermal degradation was increased by humidity. On the other hand, with respect to photosensitivity, taxifolin can be classified as class 4 (stable). Moreover, the alkaline degradation products were characterized by UPLC-ESI-MS/MS as dimers of taxifolin. These results enabled an understanding of the intrinsic lability of taxifolin, contributing to the development of stability-indicating methods, and of appropriate drug release systems, with the aims of preserving its stability and improving its bioavailability.

Antioxidant Capacity of Thistle (Cirsium japonicum) in Various Drying Methods and their Protection Effect on Neuronal PC12 cells and Caenorhabditis elegans

The aim of this study was, firstly, to evaluate the phenol profile of thistle (Cirsium japonicum, CJ) by High performance liquid chromatography-electrospray ionization–mass spectrometry (HPLC–ESI–MS), dried by different methods (90 °C hot-air, 70 °C hot-air, shade-, and freeze-drying). Secondly, we aimed to evaluate the relationship between phenolic compounds content and antioxidant properties. CJ contained chlorogenic acid, linarin, and pectolinarin. Total phenolic contents of CJ significantly decreased under hot-air-drying condition, especially chlorogenic acid contents in CJ have been reduced by 85% and 60% for 90 °C and 70 °C hot-air-drying, respectively. We evaluated the protective effect on adrenal pheochromocytoma (PC12) cells and Caenorhabditis elegans using shade-dried CJ, which has the largest phenolic contents and the strongest antioxidant property. CJ-treated PC 12 cells dose-dependently exhibited the protective effects against reactive oxygen species (ROS), while cell viability increases, lactate dehydrogenase release decreases, and ROS formation decreases. Furthermore, CJ has also shown protection against ROS in C. elegans. Consequently, CJ contributed to lifespan extension under ROS stress without influencing the physiological growth.

Enhanced transition metal oxide based peroxymonosulfate activation by hydroxylamine for the degradation of sulfamethoxazole

The enhanced peroxomonosulfate (PMS) activation and sulfamethoxazole (SMZ) degradation performances and mechanisms by hydroxylamine (HA) in the presence of three transition metal oxides (MxOy), hematite (α-Fe2O3), cobalt oxide (Co2O3) and copper oxide (CuO) were comprehensive investigated. The results showed that proper addition of hydroxylamine (HA) can greatly promote the degradation of SMZ in the three MxOy/PMS systems. The results of electron paramagnetic resonance (EPR) study and quenching experiment suggested that OH was the dominating reactive oxygen species (ROS) in the α-Fe2O3/HA/PMS and Co2O3/HA/PMS systems, while in CuO/HA/PMS system, the activated-PMS on the surface of CuO was concluded to be responsible for SMZ degradation instead of free radicals. Furthermore, the intermediates of SMZ in the systems were detected by a high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) and the degradation pathways of SMZ system were inferred, the results indicated that due to the difference of the dominating ROS and the attack order against oxidation sites, SMZ was degraded in different pathways in α-Fe2O3/HA/PMS, Co2O3/HA/PMS and CuO/HA/PMS system. α-Fe2O3, CuO and Co2O3, could maintain stable catalytic activity in the respective reaction systems and could be efficiently recycled.

Stable isotope labeling combined with liquid chromatography-tandem mass spectrometry for comprehensive analysis of short-chain fatty acids

Short-chain fatty acids (SCFAs) are one class of bacterial metabolites mainly formed by gut microbiota from undigested fibers and proteins. These molecules are able to mediate signal conduction processes of cells, acting as G protein-coupled receptors (GPR) activators and histone deacetylases (HDAC) inhibitors. It was reported that SCFAs were closely associated with various human diseases. However, it is still challenging to analyze SCFAs because of their diverse structures and broad range of concentrations. In this study, we developed a highly sensitive method for simultaneous detection of 34 SCFAs by stable isotope labeling coupled with ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS/MS) analysis. In this respect, a pair of isotope labeling reagents, N-(4-(aminomethyl)benzyl)aniline (4-AMBA) and N-(4-(aminomethyl)benzyl)aniline-d5 (4-AMBA-d5), were synthesized to label SCFAs from the feces of mice and SCFA standards, respectively. The 4-AMBA-d5 labeled SCFAs were used as internal standards to compensate the ionization variances resulting from matrix effect and thus minimize quantitation deviation in MS detection. After 4-AMBA labeling, the retention of SCFAs on the reversed-phase column increased and the separation resolution of isomers were improved. In addition, the MS responses of most SCFAs were enhanced by up to three orders of magnitude compared to unlabeled SCFAs. The limits of detection (LODs) of SCFAs were as low as 0.005 ng/mL. Moreover, good linearity for 34 SCFAs was obtained with the coefficient of determination (R2) ranging from 0.9846 to 0.9999 and the intra- and inter-day relative standard deviations (RSDs) were <17.8% and 15.4%, respectively, indicating the acceptable reproducibility of the developed method. Using the developed method, we successfully quantified 21 SCFAs from the feces of mice. Partial least squares discriminant analysis (PLS-DA) and t-test analysis showed that the contents of 9 SCFAs were significantly different between Alzheimer's disease (AD) and wide type (WT) mice fecal samples. Compared to WT mice, the contents of propionic acid, isobutyric acid, 3-hydroxybutyric acid, and 3-hydroxyisocaleric acid were decreased in AD mice, while lactic acid, 2-hydroxybutyric acid, 2-hydroxyisobutyric acid, levulinic acid, and valpronic acid were increased in AD mice. These significantly changed SCFAs in the feces of AD mice may afford to a better understanding of the pathogenesis of AD. Taken together, the developed UHPLC-ESI-MS/MS method could be applied for the sensitive and comprehensive determination of SCFAs from complex biological samples.

Evaluating iopamidol degradation performance and potential dual-wavelength synergy by UV-LED irradiation and UV-LED/chlorine treatment

This study revealed the iopamidol degradation performance and the synergistic effect of dual-wavelength ultraviolet light-emitting diodes (UV-LEDs). It was found that the dual-wavelength irradiation (265 and 280 nm) can promote iopamidol degradation during both UV-LED alone and UV-LED/chlorine processes (p < 0.05). The effects of key experimental parameters including pH, chlorine dosage and water matrix during UV-LED/chlorine process were evaluated. Peak degradation rate was observed at pH 7.0 due to the combined effects of the quantum yield of aquatic chlorine photolysis (Φchlorine) and absorptivity of chlorine. The destruction pathways of iopamidol in the UV-LED/chlorine process were proposed by Ultra Performance Liquid Chromatography-Electrospray Ionization-mass spectrometry. Additionally, an opposite trend of iodinated trihalomethane (I-THM) formation during subsequent chlorination between Milli-Q and real waters with prolonging irradiation time was observed, while other detected disinfection by-product (DBP) formation showed the same variation in Milli-Q and real waters. The UV-LED/chlorine treatment using dual-wavelength can enhance iopamidol degradation significantly, but it also promoted I-THM formation in real water, indicating the need for evaluating DBPs before the application of UV-LED/chlorine process in drinking water treatment.

Lipidomics Studies on Mitochondrial Damage of Saccharomyces cerevisiae Induced by Heavy Ion Beam Radiation

Abstract Ultra high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS) technique combined with multivariate and univariate data analysis methods was used to analyze lipid metabolomics of mitochondria-damaged Saccharomyces cerevisiae (ResD-4) after heavy ion beam radiation. The composition of lipid metabolites in Control and ResD-4 was detected, and a total of 648 kinds of lipid molecules were identified. The results showed that the orthogonal partial least squares discriminant analysis (OPLS-DA) could accurately distinguish the lipid metabolites of ResD-4 and Control. On the basis of variable importance for the projection (VIP), variation multiple (FC) and difference analysis (p), 12 subfamilies, 54 types of significant difference in lipid molecules were finally screened including DG (16:0/18:1), LPC (18:1), LPE (16:0), LPI (18:1), LPS (18:1), PA (16:0/18:1), PC (31:1), PE (16:0/10:0), PI (15:0/18:1), PS (16:0/16:1), SQDG (37:4), TG (15:0/16:0/18:1), etc. Significant differences in the expression level of lipid molecules showed that the expression levels of DG, TG, SQDG, PA, PC, PI, LPC, LPE and LPI were up-regulated, and PE, PS and LPS were down-regulated. The results showed that S. cerevisiae might respond by adjusting the content of lipid components after mitochondrial damage caused by heavy ion beam radiation. The lipid molecules with significant difference expression level might be potential markers for S. cerevisiae mitochondrial damage induced by heavy ion beam radiation.

Aqueous extract of Eruca Sativa protects human spermatozoa from mitochondrial failure due to bisphenol A exposure

Medicinal plants are suggested to counteract health disorders from chemical pollutants. Here we explored the possible ameliorative effect of Eruca sativa aqueous extract (ESAE) on in vitro acute functional disturbance induced by Bisphenol A (BPA), a disruptor model in human spermatozoa. Phytochemical screening, high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) analysis and 2,2'-azino-bis [3-ethylbenzthiazoline-6-sulphonic acid]/α,α-diphenyl-β-picrylhydrazyl (ABTS/DPPH) tests disclosed antioxidant properties of ESAE, ascribed to polyphenols and flavonoids. The toxicological impact of BPA on sperm viability and motility was detected for concentration greater than 10 μM but co-incubation with ESAE recovered sperm function at low concentration (15.62 μg/ml). BPA reduced mitochondrial membrane potential (ΔΨm), with no impact on plasma membrane potential (ΔΨp). At low doses, ESAE recovered ΔΨm but higher doses were associated with impairment of both ΔΨm and ΔΨp. ESAE protects towards in vitro BPA-mediated toxicity and its possible use as complementary treatment for male reproductive disorders is critically discussed.

Antioxidant Capacity and UPLC-PDA ESI-MS Phenolic Profile of Stevia rebaudiana Dry Powder Extracts Obtained by Ultrasound Assisted Extraction

Stevia leaves, which are commonly used as a natural sweetener in food products, have increased in importance for antioxidant delivery due to their high content of phenolic compounds. In this study, the influence of the drying process on stevia leaves, with regards to phenolic content and antioxidant activity during drying kinetics 40 °C for 7 h, was studied. The effect of solvent concentration and extraction time using a 32 factorial design on total phenol content (TPC), and on antioxidant activity of extracts obtained from dried stevia leaves, by ultrasound assisted extraction (UAE) as alternative method was evaluated. Steviol glycosides contents were also evaluated by a conventional and UAE method. Phenols identification, quantification and purification were performed by Ultra Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (UPLC-ESI-MS), Ultra Performance Liquid Chromatography-Photodiode Array (UPLC-PDA) and advanced automated flash purification, respectively. Drying time affected the moisture content of stevia leaves. A constant weight was reached after six hours of drying, and higher antioxidant activity was observed, while the highest TPC was obtained after seven hours of drying. The highest TPC (91.57 ± 8.8 mg GAE/g dw) and antioxidant activity (603.24 ± 3.5 μmol TE/g dw) in UAE method was obtained when ethanol 50% at 5 min was used. Steviol glycosides extracted by UAE were recorded with a content of 93.18 ± 1.36 mg/g dw and 98.97 ± 1.75 mg/g dw for stevioside and rebaudioside A respectively. Six phenolic compounds including four phenolic acids and two flavonoids were identified and quantified by UPLC-PDA, and confirmed by ESI-MS reporting its fragmentation pattern. Diosmin and chlorogenic acid were the most abundant compounds with values of 2032.36 μg/mL and 434.95 μg/mL respectively. As a novelty we found that the antioxidant activity evaluated in partially purified fractions suggested that biological activity might be attributed to the synergistic effect of the six phenols present in the stevia leaves extract. In addition to its sweeting properties, stevia leaves constitute a potential source of polyphenolic compounds, with antioxidant activity that could be used as a food additive.

Spatial Distribution Patterns of Root-Associated Bacterial Communities Mediated by Root Exudates in Different Aged Ratooning Tea Monoculture Systems.

Positive plant–soil feedback depends on beneficial interactions between roots and microbes for nutrient acquisition; growth promotion; and disease suppression. Recent pyrosequencing approaches have provided insight into the rhizosphere bacterial communities in various cropping systems. However; there is a scarcity of information about the influence of root exudates on the composition of root-associated bacterial communities in ratooning tea monocropping systems of different ages. In Southeastern China; tea cropping systems provide the unique natural experimental environment to compare the distribution of bacterial communities in different rhizo-compartments. High performance liquid chromatography–electrospray ionization–mass spectrometry (HPLC–ESI–MS) was performed to identify and quantify the allelochemicals in root exudates. A high-throughput sequence was used to determine the structural dynamics of the root-associated bacterial communities. Although soil physiochemical properties showed no significant differences in nutrients; long-term tea cultivation resulted in the accumulation of catechin-containing compounds in the rhizosphere and a lowering of pH. Moreover; distinct distribution patterns of bacterial taxa were observed in all three rhizo-compartments of two-year and 30-year monoculture tea; mediated strongly by soil pH and catechin-containing compounds. These results will help to explore the reasons why soil quality and fertility are disturbed in continuous ratooning tea monocropping systems; and to clarify the associated problems.

Glycyrrhetinic Acid Accelerates the Clearance of Triptolide through P-gp In Vitro.

Triptolide (TP) is an active ingredient isolated from Tripterygium wilfordii Hook. f. (TWHF), which is a traditional herbal medicine widely used for the treatment of rheumatoid arthritis and autoimmune disease in the clinic. However, its adverse reactions of hepatotoxicity and nephrotoxicity have been frequently reported which limited its clinical application. The aim of this study was to investigate the mechanism of glycyrrhetinic acid (GA) effecting on the elimination of TP in HK-2 cells and the role of the efflux transporters of P-gp and multidrug resistance-associated proteins (MRPs) in this process. An ultra performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS) analytical method was established to determine the intracellular concentration of TP. In order to study the role of efflux transporters of P-gp and MRPs in GA impacting on the accumulation of TP, the inhibitors of efflux transporters (P-gp: verapamil; MRPs: MK571) were used in this study. The results showed that GA could enhance the elimination of TP and reduce the TP accumulation in HK-2 cells. Verapamil and MK571 could increase the intracellular concentration of TP; in addition, GA co-incubation with verapamil significantly increased the TP cellular concentration compared with the control group. In conclusion, GA could reduce the accumulation of TP in HK-2 cells, which was related to P-gp. This is probably one of the mechanisms that TP combined with GA to detoxify its toxicity. Copyright © 2017 John Wiley & Sons, Ltd.

Allium hookeri root extract exerts anti-inflammatory effects by nuclear factor-\u03baB down-regulation in lipopolysaccharide-induced RAW264.7 cells

BackgroundAllium hookeri (AH) is widely consumed as a vegetable and herbal medicine in southeastern Asia. AH has been reported antioxidant, antimicrobial, improvement of bone health and antidiabetic effects. In the present study, we investigated the inhibitory effect of a methanol extract of AH root (AHE) on inflammatory response in lipopolysaccharide (LPS)-induced RAW264.7 cells.MethodsInitially, characterization of organic sulfur compounds in AHE was determined using high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). Cells were incubated with LPS and AHE for 24 h. The productions of nitric oxide (NO), reactive oxygen species (ROS), and inflammation-related cytokines were examined. Gene and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were assessed by polymerase chain reaction and Western blotting. Key factor, nuclear factor kappa B (NF-κB) was also determined.ResultsAHE contained organosulfur compounds such as alliin and S-allylcysteine by HPLC-ESI-MS. AHE significantly inhibited NO, ROS, and cytokines production in LPS-induced RAW264.7 cells. In addition, AHE treatment inhibited iNOS and COX-2 mRNA and protein levels, leading to a decrease in iNOS-derived NO level. Furthermore, NF-κB activation was, at least in part, suppressed by AHE treatment.ConclusionOur data suggest that AHE treatment inhibits the inflammation condition through suppression of iNOS and COX-2 expression via NF-κB down-regulation.

Determination of hexabromocyclododecanes in ambient air by high performance liquid chromatography- electrospray ionization-mass spectrometry

A high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) method was developed for the determination of hexabromocyclododecanes (HBCDs) in ambient air samples. The samples were extracted by Soxhlet extractor with hexane, then purified on the composite gel column. At first, the interfering substances were rinsed with 50 mL hexane and 100 mL hexane-dichloromethane (9:1, v/v), then 180 mL hexane -dichloromethane (4:1, v/v) was used to elute the targets. The compounds were separated by gradient elution with acetonitrile-methanol-water as mobile phases on a UF-ODS column (150 mm×2.1 mm, 3.0 μm). Electrospray ionization negative ion source and selective ion monitoring (SIM) mode were adopted in MS detection. The results showed that α -HBCD, β -HBCD and γ -HBCD could be well separated, and the chromatographic peak area ratio of α -HBCD, β -HBCD and γ -HBCD to internal standard D18- γ -HBCD with their concentrations had a good linear relationship, with the correlation coefficients (R) ≥ 0.9988. The limits of detection (LODs, S/N=3) of α -HBCD, β -HBCD and γ -HBCD were 0.4, 0.5 and 0.4 μg/L, respectively. The limits of quantification (LOQs, S/N=10) were 1.4, 1.6 and 1.3 μg/L, respectively. The method detection limits (MDL) were 0.13, 0.17 and 0.13 pg/m3 (n=5), respectively. The recoveries of HBCDs spiked in the actual air samples were in the range of 74.8%-95.8%. It is demonstrated that the method has high sensitivity and good selectivity, and can meet the requirement of monitoring and analyzing HBCDs in air samples.

Optimization of Yield for Extraction of an Essential Oil from Cinnamon Using Microwave-Assisted Extraction

Sicklepod (Senna obtusifolia L.) is synonymous both with Cassia tora L. and Cassia obtusifolia L.). It is usually viewed as a noxious weed in crop fields in southeastern United States. This plant, however, has a long history of use in traditional medicine in oriental countries. It is a prolific seed producer the constituents of which include: polysaccharides, proteins, highly colored low fat content and many phenolic compounds. The phenolic components are usually described as toxic, although recent literature shows many of these to exhibit potent therapeutic properties for human health. Pursuant to this as part of our continuing interest in the plant, we have expanded our study of the seed by extracting a mixture of anthraquinone and naphthopyrone glycosides from S. obtusifolia seed obtained from North Carolina. A survey of the composition of the extract was affected using High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (HPLC-ESI-MS) with a variety of collision induced dissociation (CID) experiments. The major constituents of the mixture produced HPLC-ESI-MSn data consistent with: chrysophanic acid tetraglycoside; rubrufusarin and toralactone di-, tri- and tetraglycosides; torachrysone ester, di-, tri-, tetra- and pentaglycosides and cassialactone tetraglycoside. The naphthopyrone glycosides and related phenolic compounds in the seed are value-added medicinal co-products to the galactomannan polysaccharides of S. obtusifolia. FT-IR spectra of the mixture corroborate the chromatographic information obtained of the mixture of anthraquinone glycosides.

Simultaneous quantitation of six aconitum alkaloids and three flavonoids in the herb couple of radix aconiti lateralis-radix glycyrrhizae (Fuzi-Gancao) by UHPLC-ESI-MS/MS.

Background:Fuzi–Gancao herb couple is one of the commonly used herb couples involved in the traditional Chinese medicine formulations, with radix aconiti lateralis (Fuzi in Chinese) and radix glycyrrhizae (Gancao in Chinese) as a ratio of 1:1. Alkaloids and flavonoids were considered as the main active ingredients of Fuzi–Gancao herb couple. However, no analytical methods have been reported to quantitatively analyze these activity ingredients in Fuzi–Gancao herb couple simultaneously.Objective:To develop a simple, rapid, and sensitive UHPLC-MS/MS method for simultaneous quantitation of six alkaloid and three flavonoid compounds, namely, aconitine (AC), mesaconitine (MA), hypaconitine (HA), benzoylaconitine (BAC), benzoylmesaconitine (BMA), benzoylhypaconitine (BHA), liquiritin, isoliquiritin, and licochalcone A (LCA) in Fuzi–Gancao herb couple.Materials and Methods:The chromatographic separation was achieved using a reversed phase C18 column and a mobile phase consisted of water (0.1% formic acid in water, v/v) and acetonitrile. The detection was achieved in multiple reaction monitoring modes. The optimal mass transition ion pairs (m/z) for quantitation were 646.3/586.5 for AC, 632.4/572.5 for MA, 616.3/556.4 for HA, 604.5/572.5 for BAC, 590.4/540.4 for BMA, 574.1/542.5 for BHA, 419.4/257.1 for liquiritin, 419.4/257.1 for isoliquiritin, and 339.2/121.1 for LCA.Results:Good linearity was observed in validated concentration range for each analyte (r > 0.9992), and the intra- and inter-day precisions were <3.12% and 3.65%, respectively. The recovery ranged from 85.36% to 110.14%.Conclusions:The results demonstrated that the method developed was reliable, rapid, and specific. Moreover, this method was successfully applied to control the quality of Fuzi–Gancao herb couple.SUMMARY A simple, rapid, and sensitive UHPLC-MS/MS method for simultaneous quantitation of six alkaloid and three flavonoid compounds in Fuzi–Gancao herb couple has been developed. Abbreviations used: UHPLC-ESI-MS/MS: Ultra High Performance Liquid Chromatography-electrospray ionization-mass spectrometry; RSD: Relative standard deviations; LOD: Limit of detection; LOQ: Limit of quantification; MRM: Multiple reaction monitor; TCMs: Traditional Chinese medicines.

Phytochemical Profiling of Flavonoids, Phenolic Acids, Terpenoids, and Volatile Fraction of a Rosemary (Rosmarinus officinalis L.) Extract.

This paper presents a comprehensive analysis of the phytochemical profile of a proprietary rosemary (Rosmarinus officinalis L.) extract rich in carnosic acid. A characterization of the (poly)phenolic and volatile fractions of the extract was carried out using mass spectrometric techniques. The (poly)phenolic composition was assessed by ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MSn) and a total of 57 compounds were tentatively identified and quantified, 14 of these being detected in rosemary extract for the first time. The rosemary extract contained 24 flavonoids (mainly flavones, although flavonols and flavanones were also detected), 5 phenolic acids, 24 diterpenoids (carnosic acid, carnosol, and rosmanol derivatives), 1 triterpenoid (betulinic acid), and 3 lignans (medioresinol derivatives). Carnosic acid was the predominant phenolic compound. The volatile profile of the rosemary extract was evaluated by head space solid-phase microextraction (HS-SPME) linked to gas chromatography-mass spectrometry (GC-MS). Sixty-three volatile molecules (mainly terpenes, alcohols, esters, aldehydes, and ketones) were identified. This characterization extends the current knowledge on the phytochemistry of Rosmarinus officinalis and is, to our knowledge, the broadest profiling of its secondary metabolites to date. It can assist in the authentication of rosemary extracts or rosemary-containing products or in testing its bioactivity. Moreover, this methodological approach could be applied to the study of other plant-based food ingredients.