Non-target screening of volatile organic compounds in spray-type consumer products and their potential health risks.

Widespread use of spray-type consumer products can raise significant concerns regarding their effects on indoor air quality and human health. In this study, we conducted non-target screening using gas chromatography-mass spectrometry (GC-MS) to analyze VOCs in 48 different spray-type consumer products. Using this approach, we tentatively identified a total of 254 VOCs from the spray-type products. Notably, more VOCs were detected in propellant-type products which are mostly solvent-based than in trigger-type ones which are mostly water-based. The VOCs identified encompass various chemical classes including alkanes, cycloalkanes, monoterpenoids, carboxylic acid derivatives, and carbonyl compounds, some of which arouse concerns due to their potential health effects. Alkanes and cycloalkanes are frequently detected in propellant-type products, whereas perfumed monoterpenoids are ubiquitous across all product categories. Among the identified VOCs, 12 compounds were classified into high-risk groups according to detection frequency and signal-to-noise (S/N) ratio, and their concentrations were confirmed using reference standards. Among the identified VOCs, D-limonene was the most frequently detected compound (freq. 21/48), with the highest concentration of 1.80 mg/g. The risk assessment was performed to evaluate the potential health risks associated with exposure to these VOCs. The non-carcinogenic and carcinogenic risks associated with the assessed VOC compounds were relatively low. However, it is important not to overlook the risk faced by occupational exposure to these VOCs, and the risk from simultaneous exposure to various VOCs contained in the products. This study serves as a valuable resource for the identification of unknown compounds in the consumer products, facilitating the evaluation of potential health risks to consumers.

Fatty acids, triterpenes and cycloalkanes in ficus seed oils.

The compositions of the seed oils obtained by hexane extraction of three members of the Ficus genus of the Moraceae plant family was determined, namely Ficus nota, Ficus septica, Ficus ulmifolia. Linolenic acid is the most prominent fatty acid in the seed oils followed by linoleic acid, with these two fatty acid comprising about 75% of the fatty acids in the oils. The high level of polyunsaturated fatty acids coincides with high levels of these acids predominating among the fatty acids observed in various plant parts of other Ficus species. Besides the fatty acids, a variety of phytochemicals also found in other plant parts of Ficus species were observed in the seed oils, including squalene, pentacyclic triterpenes such as α-amyrin, ß-amyrin and lupeol, as well as sterols such as cholesterol and γ-sitosterol, the former at unusually elevated levels. The levels of these phytochemicals vary from species to species and location of harvest, with F. ulmifolia showing by far the highest level of these materials and with α-amyrin, ß-amyrin and lupeol being the most common, their amounts exceeding those of fatty acids for samples from one specific location. Surprisingly, low levels of macrocyclic alkanes in the range of C24-C30 were identified.

Elimination of typical polycyclic musks in a full-scale membrane bioreactor combined with anaerobic-anoxic-oxic process in municipal wastewater treatment plant.

The objective of this study was to investigate the removal of 11 synthetic polycyclic musks in a municipal wastewater treatment plant located in Jilin, China, by using a membrane bioreactor combined with anaerobic-anoxic-oxic process. The analysis of synthetic polycyclic musks was conducted with gas chromatography/mass spectrometry after solid-phase extraction. The removal efficiency of 11 synthetic polycyclic musks ranged from 65.9% (3-methylcyclopentadecanone) to 84.6% (Galoxolide) in the influent. Along the treatment process, it was observed that the anaerobic tank could remove the synthetic polycyclic musks effectively whereas the role of the membrane was to the musks, which could be ascribed to the relatively strong hydrophobic property of the musks. The sludge-water distribution coefficients (Kd values) as indicator of adsorption propensity for the sludge from anaerobic, anoxic, oxic and membrane tanks were measured. The high value of Kd, above 5.0 litres per gram of suspended solids, showed most of the musks could be removed by sludge through the adsorption process; thus the removal rate from the water phase caused by adsorption in the wastewater treatment plant can be predicted.

Quality markers of animal medicinal materials: Correlative analysis of musk reveals distinct metabolic changes induced by multiple factors.

BACKGROUND: Common farming environmental elements, such as longitude, latitude, and altitude, and physiological conditions, such as age and body weight, are thought to influence medicinal animal homeostasis and material quality by altering endocrine functions for primary and secondary metabolite formation. However, the currently available methods for evaluating complex components of traditional Chinese animal medicines have insufficient sensitivity and specificity. PURPOSE: Characterizing the primary/secondary metabolomes of medicinal animals is essential for understanding their material basis, controlling product quality, and reflecting on distribution interactions. Therefore, this study aimed to screen ecological- and physiological-related metabolites in captive Moschus berezovskii throughout the collection period based on the quality marker (Q-marker) concept. STUDY DESIGN AND METHODS: Fifty-one musk deer samples from 12 different distribution farms ranging in age from 2 to 11 years were enrolled. Differentially expressed musk metabolites were assessed via chromatography-tandem mass spectrometry technologies. A metabolome that mapped connections among these factors was established using chemometric and topological calculations. RESULTS: Statistical analysis revealed that muscone, cis-9-hexadecenal, antioxidant 2264, prasterone-3-sulfate, androstan-17-one, and 1,2-benzenedicarboxylic acid showed significantly altered expression. Partial least squares (PLS) regression analysis of qualified data for these 6 secondary metabolites (active components) demonstrated that age is the most important factor underlying the varying levels of muscone, androstan-17-one and 1,2-benzenedicarboxylic acid. Furthermore, weight was the most important factor for cis-9-hexadecenal, longitude was important for antioxidant 2264, latitude was important for prasterone-3-sulfate, and altitude was important for antioxidant 2264, androstan-17-one and 1,2-benzenedicarboxylic. Metabolite analysis within the MetaboAnalyst (MetPA) suite showed that 18 candidate biomarker metabolites were screened, including allantoin, glycine, serine, creatine, alanine, taurine, lactate, 2-oxoglutarate (2-OG), fumarate, proline, xanthine, cytosine, carnitine, arginine, threonine, aspartate, and urea. Metabolic network analysis showed 4 important pathways that were involved: arginine and proline metabolism, the urea cycle, aspartate metabolism, and glycine, serine and threonine metabolism. CONCLUSION: Using this combined metabolomic and chemometric approach, this study was successful in screening Q-markers for musk quality control and provided new insights into correlations among "ecological & physiological factors→Q-markers→metabolites", which potentially provides crucial information for musk breeding and material quality control.

Live-cell Measurement of Odorant Receptor Activation Using a Real-time cAMP Assay.

The enormous sizes of the mammalian odorant receptor (OR) families present difficulties to find their cognate ligands among numerous volatile chemicals. To efficiently and accurately deorphanize ORs, we combine the use of a heterologous cell line to express mammalian ORs and a genetically modified biosensor plasmid to measure cAMP production downstream of OR activation in real time. This assay can be used to screen odorants against ORs and vice versa. Positive odorant-receptor interactions from the screens can be subsequently confirmed by testing against various odor concentrations, generating concentration-response curves. Here we used this method to perform a high-throughput screening of an odorous compound against a human OR library expressed in Hana3A cells and confirmed that the positively-responding receptor is the cognate receptor for the compound of interest. We found this high-throughput detection method to be efficient and reliable in assessing OR activation and our data provide an example of its potential use in OR functional studies.

The musk chemical composition and microbiota of Chinese forest musk deer males.

Male musk deer secrete musk from the musk gland located between their naval and genitals. Unmated male forest musk deer generate a greater amount of musk than mated males, potentially allowing them to attract a greater number of females. In this study, we used gas chromatography and mass spectrometry (GC/MS) to explore musk chemical composition of the musk pods of captive mated and unmated sexually mature Chinese forest musk deer and used next-generation sequencing to intensively survey the bacterial communities within them. Analysis of the chemical composition of the musk showed that unmated males have more muscone and cholesterol. Features of the musk16S rRNA gene showed that mated Chinese forest musk deer have both a greater Shannon diversity (p < 0.01) and a greater number of estimated operational taxonomic units than unmated ones; many bacterial genera were overrepresented in unmated Chinese forest musk deer males. Members of these genera might be involved in musk odor fermentation. PICRUSt analysis revealed that metabolic pathways such as aldosterone-regulated sodium reabsorption, metabolism of terpenoids and polyketides, flavone and flavonol biosynthesis, and isoflavonoid biosynthesis were enriched in the musk of unmated Chinese forest musk deer males.

Fast and direct quantification of underivatized muscone by ultra performance liquid chromatography coupled with evaporative light scattering detection.

A new reversed phase ultra performance liquid chromatography coupled with evaporative light scattering detection is developed for the fast and direct quantification of underivatized muscone in precious herbal medicine musk. Separation of muscone was achieved on a Waters Acquity BEH C18 (50 × 2.1 mm id, 1.7 µm) column. The runtime was as short as 5 min. The mode of evaporative light scattering detection was set at Impact On. The influence of evaporative light scattering detection condition on sensitivity was investigated. The optimized condition was: drift tube temperature at 30°C, gas flow rate 4.2 L/min. The method was validated with respect to the precision, sensitivity, accuracy, linearity, stability, and robustness were measured in this paper. The calibration curves showed good linear regression (r = 0.9914) within the test range. The recovery rate was 98.6%. The limit of detection for muscone was 2.0 ng. The validated method was rapid, simple, reproducible, and convenient for the quantification of muscone in musk and the related products.

Gas-chromatographic enantioseparation of unfunctionalized chiral hydrocarbons: an overview.

Analytical gas-chromatographic enantioseparations of unfunctionalized chiral hydrocarbons (cycloalkanes and alkanes) on modified cyclodextrins with high-resolution capillary columns are reviewed. Due to the lack of functional groups of the hydrocarbons, enantiorecognition in the presence of cyclodextrins is ascribed to weak van der Waals forces. Thermodynamic parameters of enantiorecognition between four chiral alkanes and octakis(6-O-methyl-2,3-di-O-pentyl)-γ-cyclodextrin (Lipodex G) have been determined. The possible role of molecular inclusion is indicated by the complete loss of enantioselectivity when the cyclodextrins are replaced by the corresponding linear dextrins. The substitution pattern and cavity size of the modified cyclodextrins have a pronounced effect on the degree of enantiorecognition observed. On mixed binary cyclodextrin stationary phases, all C7 and C8 chiral alkanes possessing one stereogenic center can be enantioseparated simultaneously. The methodology has been used to determine enantiomeric excesses, ee, of alkanes formed by the enantioselective catalytic hydrogenation of prochiral alkenes. The novel online coupling of enantioselective gas chromatography with proton nuclear magnetic resonance spectroscopy is demonstrated for 2,4-dimethylhexane and Lipodex G.

[Determination method of muscone in rat intestinal perfusate by GC-MS/MS and its intestinal absorption kinetic characteristics in rats].

OBJECTIVE: To establish the method for determining muscone in rat intestinal perfusate by GC-MS/MS and study its intestinal absorption kinetic characteristics in rats. METHOD: The GC-MS/MS method was used to determine the content of muscone in rat intestinal circulation fluid. In situ intestinal circulation perfusion was adopted to study absorption kinetics of muscone in rats. RESULT: Muscone was proved to be well absorbed in each section of small intestine. Its absorption rate constants (Ka) and the absorption rate (A) in the rat intestine showed duodenum > jejunum (P < 0.05) , duodenum > ileum (P < 0.01). Its Ka, A and t1/2 in rat small intestine was 0.990 h(-1) , 43.58% and 0.705h, respectively. CONCLUSION: Muscone was well absorbed in each intestinal section, with duodenum better than jejunum (Ka, T1/2, P < 0.05) significantly better than ileum (Ka, T1/2, P < 0.01; A, P < 0.05). There is no obvious statistical difference between jejunum and ileum.

Fractionation by liquid chromatography combined with comprehensive two-dimensional gas chromatography-mass spectrometry for analysis of cyclics in oligomerisation products of Fischer-Tropsch derived light alkenes.

In oligomerisation products of High Temperature Fischer-Tropsch (HTFT) derived light alkenes using a solid phosphoric acid (SPA) catalyst, the presence of cyclics was presumed although their occurrence could not be explained by the generally accepted oligomerisation mechanism. Notwithstanding the use of GC×GC-TOFMS, the cyclic alkanes could not be differentiated from the alkenes. On the one hand, compounds co-eluted in GC×GC and, on the other hand, MS cannot distinguish between these classes because of identical molecular masses and very similar mass fragmentation patterns. An LC pre-fractionation procedure utilising a silver-modified column was developed to separate the saturates from the unsaturates. Using this approach we were able, for the first time, to confirm the presence of cyclics, probably resulting from secondary reactions, in HTFT oligomerisation products. The occurrence of cyclics can be an indication of the beginning of carbonaceous deposit formation that could eventually lead to catalyst deactivation.

Electrochromatography in cyclic olefin copolymer microchips: a step towards field portable analysis.

In order to develop a portable and disposable instrument for on-site analysis of neutral compounds, a lauryl methacrylate monolith has been synthesized into a cyclic olefin copolymer microdevice for reversed-phase electrochromatography purposes. This monolith was tested in capillary to evaluate electrochromatographic performances in terms of electroosmotic flow (EOF) mobility, retention and efficiency prior to its transfer into the microfluidic device. The produced monolithic bed exhibited a good run-to-run repeatability, column-to-column reproducibility and batch-to-batch reproducibility, with relative standard deviation (RSD) values below 9% for EOF mobility, retention factors and heights of theoretical plate. The electrochromatographic performances of the monolith were optimized by reducing irradiation time. Photopolymerization time of 10 min was found to be the best process in order to obtain a robust, retentive and efficient system. The on-chip performances of this monolith were evaluated in detail for the reversed-phase electrochromatographic separation of polycyclic aromatic hydrocarbons, with plate heights reaching down to 15 µm when working at optimal velocity. Aiming at the maximum simplification of instrumental fabrication and operation, a direct injection from a 2 µL droplet was compared with more conventional dynamic injection process.

Supercritical fluid chromatography hyphenated with twin comprehensive two-dimensional gas chromatography for ultimate analysis of middle distillates.

This paper reports the conditions of online hyphenation of supercritical fluid chromatography (SFC) with twin comprehensive two-dimensional gas chromatography (twin-GCxGC) for detailed characterization of middle distillates; this is essential for a better understanding of reactions involved in refining processes. In this configuration, saturated and unsaturated compounds that have been fractionated by SFC are transferred on two different GC x GC columns sets (twin-GCxGC) placed in the same GC oven. Cryogenic focusing is used for transfer of fractions into the first dimension columns before simultaneous GCxGC analysis of both saturated and unsaturated fractions. The benefits of SFC-twin-GC x GC are demonstrated for the extended alkane, iso-alkane, alkene, naphthenes and aromatics analysis (so-called PIONA analysis) of diesel samples which can be achieved in one single injection. For that purpose, saturated and unsaturated compounds have been separated by SFC using a silver loaded silica column prior to GC x GC analysis. Alkenes and naphthenes are quantitatively recovered in the unsaturated and saturated fractions, respectively, allowing their identification in various diesel samples. Thus, resolution between each class of compounds is significantly improved compared to a single GCxGC run, and for the first time, an extended PIONA analysis of diesel samples is presented.

Temporal trends of hexabromocyclododecanes (HBCDs) and polybrominated diphenyl ethers (PBDEs) and detection of two novel flame retardants in marine mammals from Hong Kong, South China.

Concentrations of hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs), and three novel flame retardants, namely2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB), bis-(2-ethylhexyl)-tetrabromophthalate (TBPH), and hexachlorocyclopentadienyldibromocyclooctane (HCDBCO), were determined in blubber samples of Indo-Pacific humpback dolphins (Sousa chinensis) and finless porpoises (Neophocaena phocaenoides). The levels of HBCDs and PBDEs in cetacean samples ranged from 4.1 to 519 and 103 to 51,100 ng/g lw, respectively. A significant increasing trend of SigmaHBCDs was observed in dolphin samples from 1997 to 2007 with an estimated annual rate of 5%, whereas no significant temporal trends of SigmaPBDEs appeared over the sampling period. This pattern may be attributed to the increasing usage of HBCDs following the restriction/voluntary withdrawal of the production and use of PBDE commercial mixtures in several countries. HCDBCO was not found in the blubber samples. This is the first report of the presence of TBB and TBPH, two new flame retardants that have previously been identified in house dust from the U.S., in marine mammals; concentrations of these compounds in dolphins and porpoises ranged from the instrumental detection limit (IDL) (<0.04) to 70 and IDL (<0.04) to 3859 ng/g lw, respectively. Levels of TBPH were comparable to SigmaHBCDs in porpoise samples. The presence of these novel flame retardants in top-trophic-level marine organisms raises concern about their release into the environment and indicates the need for further monitoring of these compounds in other environmental matrices.

Analysis of biopharmaceutical market-appropriate plastic syringe barrel for extractables.

A study was designed to evaluate a new syringe system developed specifically for sensitive pharmaceutical and biopharmaceutical drug products. An in-depth review of the extractables portion of this program is presented and includes data generated by liquid chromatography-mass spectroscopy, gas chromatography-mass spectroscopy, ion chromatography, and inductively coupled plasma of the Crystal Zenith barrel before and after sterilization. One leachable was identified after e-beam irradiation processing. This leachable, identified as an organic acid species, was then evaluated from a safety assessment viewpoint. The details of this program and associated results are explained in this report.

Pollutant emissions from gasoline combustion. 1. Dependence on fuel structural functionalities.

To study the formation of air pollutants and soot precursors (e.g., acetylene, 1,3-butadiene, benzene, and higher aromatics) from aliphatic and aromatic fractions of gasoline fuels, the Utah Surrogate Mechanisms is extended to include submechanisms of gasoline surrogate compounds using a set of mechanism generation techniques. The mechanism yields very good predictions of species concentrations in premixed flames of n-heptane, isooctane, benzene, cyclohexane, olefins, oxygenates, and gasoline using a 23-component surrogate formulation. The 1,3-butadiene emission comes mainly from minor fuel fractions of olefins and cyclohexane. The benzene formation potential of gasoline components shows the following trends as functions of (i) chemical class: n-paraffins < isoparaffins < olefins < naphthalenes < alkylbenzenes < cycloparaffins < toluene; (ii) carbon number: n-butane < n-pentane < n-hexane; and (iii) branching: n-hexane < isohexane < 2,2,4-trimethylpentane < 2,2,3,3-tetramethylbutane. In contrast, fuel structure is not the main factor in determining acetylene formation. Therefore, matching the benzene formation potential of the surrogate fuel to that produced by the real fuel should have priority when selecting candidate surrogate components for combustion simulations.

DFT/NMR integrated approach: a valid support to the total synthesis of chiral molecules.

The analysis of the configuration of kedarcidin chromophore and palau'amine through quantum chemical calculation of Js and chemical shifts suggests a fast and convenient quantum chemical approach that can be applied prior to proceeding to the total synthesis of complex natural compounds in order to avoid loss of time and resources employed in the total synthesis of wrong diastereoisomers.

Conformational and structural analysis of exocyclic olefins and ketimines by multinuclear magnetic resonance.

The (1)H, (13)C, and (15)N NMR spectra of 5 exocyclic alkenes and 15 different ketimines obtained from cyclohexanone and derivatives using benzyl bromide and primary amines-are analyzed. Relative stereochemical and preferential conformations are determined by analyzing both the homonuclear coupling and the chemical shifts of the protons and carbon atoms in the aliphatic rings, which are directly related to the geometry of the double bond and the steric and electronic effects of the exocyclic group. In addition, the racemic mixture of the N-(4-methylcyclohexylidene)pyridine-3-amine derivative is resolved.

Measurements of secondary organic aerosol from oxidation of cycloalkenes, terpenes, and m-xylene using an Aerodyne aerosol mass spectrometer.

The Aerodyne aerosol mass spectrometer (AMS) was used to characterize physical and chemical properties of secondary organic aerosol (SOA) formed during ozonolysis of cycloalkenes and biogenic hydrocarbons and photo-oxidation of m-xylene. Comparison of mass and volume distributions from the AMS and differential mobility analyzers yielded estimates of "effective" density of the SOA in the range of 0.64-1.45 g/cm3, depending on the particular system. Increased contribution of the fragment at m/z 44, C02+ ion fragment of oxygenated organics, and higher "delta" values, based on ion series analysis of the mass spectra, in nucleation experiments of cycloalkenes suggest greater contribution of more oxygenated molecules to the SOA as compared to those formed under seeded experiments. Dominant negative "delta" values of SOA formed during ozonolysis of biogenics indicates the presence of terpene derivative structures or cyclic or unsaturated oxygenated compounds in the SOA. Evidence of acid-catalyzed heterogeneous chemistry, characterized by greater contribution of higher molecular weight fragments to the SOA and corresponding changes in "delta" patterns, is observed in the ozonolysis of alpha-pinene. Mass spectra of SOA formed during photooxidation of m-xylene exhibit features consistent with the presence of furandione compounds and nitro organics. This study demonstrates that mixtures of SOA compounds produced from similar precursors result in broadly similar AMS mass spectra. Thus, fragmentation patterns observed for biogenic versus anthropogenic SOA may be useful in determining the sources of ambient SOA.