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1.
Electronic cigarettes have achieved growing popularity since their introduction onto the European market. They are promoted by manufacturers as healthier alternatives to tobacco cigarettes, however debate among scientists and public health experts about their possible impact on health and indoor air quality means further research into the product is required to ensure decisions of policymakers, health care providers and consumers are based on sound science. This study investigated and characterised the impact of ‘vaping’ (using electronic cigarettes) on indoor environments under controlled conditions using a 30 m3 emission chamber. The study determined the composition of e-cigarette mainstream vapour in terms of propylene glycol, glycerol, carbonyls and nicotine emissions using a smoking machine with adapted smoking parameters. Two different base recipes for refill liquids, with three different amounts of nicotine each, were tested using two models of e-cigarettes. Refill liquids were analysed on their content of propylene glycol, glycerol, nicotine and qualitatively on their principal flavourings. Possible health effects of e-cigarette use are not discussed in this work. Electronic cigarettes tested in this study proved to be sources for propylene glycol, glycerol, nicotine, carbonyls and aerosol particulates. The extent of exposure differs significantly for active and passive ‘vapers’ (users of electronic cigarettes). Extrapolating from the average amounts of propylene glycol and glycerol condensed on the smoking machine filter pad to the resulting lung-concentration, estimated lung concentrations of 160 and 220 mg m−3 for propylene glycol and glycerol were obtained, respectively. Vaping refill liquids with nicotine concentrations of 9 mg mL−1 led to vapour condensate nicotine amounts comparable to those of low-nicotine regular cigarettes (0.15–0.2 mg). In chamber studies, peak concentrations of 2200 μg m−3 for propylene glycol, 136 μg m−3 for glycerol and 0.6 μg m−3 for nicotine were reached. Carbonyls were not detected above the detection limits in chamber studies. Particles in the size range of 20 nm to 300 nm constantly increased during vaping activity and reached final peak concentrations of 7 × 106 particles L−1. Moreover, the tested products showed design flaws such as leakages from the cartridge reservoirs. Possible long term effects of e-cigarettes on health are not yet known. E-cigarettes, the impact of vaping on health and the composition of refill liquids require therefore further research into the product characteristics. The consumers would benefit from harmonised quality and safety improvements of e-cigarettes and refill liquids.  相似文献   

2.
A slurry sampling flame atomic absorption spectrometric method is proposed for the determination of copper, manganese and iron in oysters (Crassostrea rhizophora), clams (Anomalocardia brasiliana) and mussels (Mytella guiyanensis; Perna perna). Optimization was carried out using univariate methodology involving the following variables: nature and concentration of the acid solution for slurry preparation, sonication time and sample mass. The optimized conditions were 80 mg of sample ground in a cryogenic mil, dilution using 1.0 mol L−1 nitric /hydrochloric acid solution, sonication time of 30 min and a slurry volume of 10 mL. The calibration curves had been prepared using standards of copper, manganese and iron also in 1.0 mol L−1 nitric/hydrochloric acid solution. This method allowed the determination of copper, manganese and iron by FAAS, with detection limits of 0.17, 0.09 and 0.46 μg g−1, respectively. The precision, expressed as relative standard deviation (RSD), are 3.0%, 2.9% and 3.8% (n=10), for concentrations of copper, manganese and iron of 17, 22 and 719 μg g−1, respectively. The accuracy of the method was confirmed by analysis of the certified oyster tissue (NIST 1566b). The proposed method was applied for the determination of copper, manganese and iron in samples of oyster, clams and mussels, collected in Ubatuba and Todos os Santos Bay, Brazil. The obtained concentrations varied between 17.1 and 143.9 μg g−1, 17.9 and 29.7 μg g−1 and 364 and 1388 μg g−1, respectively, for copper, manganese and iron. These values agree well with other data reported in the literature. The results showed no significant differences (P>0.005) using the proposed method with those obtained after complete digestion and determination by inductively coupled plasma-optical emission spectroscopy (ICP-OES).  相似文献   

3.
A fast and sensitive method has been developed for the determination of five fluoroquinolones and a quinolone in commercial bovine milk by capillary-LC–DAD–MS after simple extraction method based on milk deproteinization with 15% trichloroacetic acid. Separation was carried out in a Zorbax SB-C18 column (150 mm × 0.5 mm, 5 μm) using a mixture of acetonitrile–5 mM ammonium formate (pH 3.7) as mobile phase in gradient elution mode. The sample was prepared in a 5 mM aqueous ammonium formate buffer for focusing purposes and 20 μL were injected. Flow rate and temperature were set at 20 μL min−1 and 25 °C, respectively. Method validation was performed according to the European Commission Decision 657/2002/EC. Sample detection limits were between 2.8 and 25 μg kg−1, and good linearity was observed up to 250 μg kg−1 for all analytes. Acceptable and constant recoveries of 96% for enrofloxacin, 77% for its metabolite ciprofloxacin, and 64% for flumequine, with RSDs (n = 4) lower than 8%, were obtained at the 100 μg kg−1 maximum level permitted in milk. Recoveries between 70% and 83% were obtained when difloxacin, sarafloxacin and ofloxacin (not allowed in animals that produce milk for human consumption) were added to milk samples at levels in the range 75–150 μg kg−1. Decision limit (CCα), detection capability (CCβ), repeatability, within-laboratory reproducibility and robustness were compliant with European Union regulations.  相似文献   

4.
Biofortification of staple crops via breeding is an attractive strategy for reducing human micronutrient deficiencies. The objective of this research was to examine the concentration of carotenoids in diverse pea and chickpea accessions grown in Saskatchewan (Canada) using high performance liquid chromatography. In pea accessions mean concentration of lutein was highest (11.2 μg g−1) followed by β-carotene (0.5 μg g−1), zeaxanthin (0.3 μg g−1), and violaxanthin (0.3 μg g−1). Green cotyledon pea accessions were richer in β-carotene and total carotenoids compared to yellow cotyledon accessions. In chickpea accessions mean concentration of lutein (8.2 μg g−1) was highest followed by zeaxanthin (6.2 μg g−1), β-carotene (0.5 μg g−1), β-cryptoxanthin (0.1 μg g−1), and violaxanthin (0.1 μg g−1). Desi chickpea accessions had higher carotenoid concentration than kabuli accessions. This research identified pea and chickpea accessions that can be utilized in breeding for the improvement of carotenoid concentration through biofortification.  相似文献   

5.
A novel spectrophotometric method was developed for determination of germanium in food and fruit using p-methybenzeneazosalicylflurone as a new chromogenic reagent. Under optimum reaction conditions, the reagent reacts with germanium(IV) to form a red complex with a maximum absorption at 502 nm. The apparent molar coefficient of the complex was 2.0×105 L mol−1 cm−1, and a linear absorbance was obtained for 0–7 μg of germanium in 10 mL solution. The reaction completed rapidly and the absorbance of the complex remains stable for at least 24 h at room temperature. The effect of various substances on the determination of germanium was investigated in succession. The results indicated that all studied co-existing substances can be tolerated in considerable amounts, e.g., 4000-fold molybdenum(VI) and tin(II) do not interfere with the determination of germanium; its selectivity is obviously better than other reagents in the literature. The detection limit, calculated using three times the standard error of estimate of the calibration graph, is 0.006 μg g−1of germanium with the pre-concentration of germanium in digested solution using ferric hydroxide as the co-precipitator.  相似文献   

6.
A single-run high performance liquid chromatography (HPLC) with diode array detector (DAD) based method was developed for the separation, identification and comprehensive quantification of degradation products of ergosterol formed in oyster mushroom (Pleurotus ostreatus) after UV-B exposure. After 60 min, 10 substances involved in the photoprocess were separated, identified by their characteristic DAD spectrum and distinguished by their molecular weight, in cases where spectra were identical: vitamin D2, previtamin D2, tachysterol2, lumisterol2 and ergosterol, and, in minor quantity, their structural analogues of the 22,23-dihydroergocalciferol (vitamin D4) series. Sample preparation protocol affected the total yields and the ratios of previtamin and vitamin D2/D4. Hot alkaline hydrolysis resulted in the best digestion of the mushroom matrix and accordingly gave the highest vitamin D yield (D2: 141.32 μg g−1 dry matter, DM; D4: 22.72 μg g−1 DM). Limit of detection for vitamin D2/4 was 0.02 μg g−1 dry matter (DM) and was estimated for previtamin D2/4 (0.06 μg g−1 DM), tachysterol2/4 (0.02 μg g−1 DM) and lumisterol2/4 (0.06 μg g−1 DM). Recovery of spiked vitamin D2 was 97 ± 0.7%. The study provides an analytical tool to assess the process of vitamin D generation after UV-B treatment for the production of oyster mushrooms with a balanced nutritional profile of vitamin D compounds.  相似文献   

7.
Rice and its derivatives are important source of essential and non-essential elements. Essential elements as cobalt (Co) and selenium (Se) are vital for human homeostasis. However, non-essential elements such as arsenic (As), cadmium (Cd) and lead (Pb) may be present in rice-based food and consequently, people can be exposed—especially children and the celiac population. This study aimed to determine essentials and non-essentials elements in rice-based products and baby food and also to evaluate nutritional risk by estimating the daily intake of non-essential elements. Regarding essential elements, Co and Se presented the highest concentrations in rice flour (56 μg kg−1) and porridge (254 μg kg−1), respectively. For non-essential elements, the highest concentrations of As, Cd and Pb were 104 μg kg−1 (porridge), 16 μg kg−1 (flour), and 188 μg kg−1 (bread), respectively. Total As concentration in Brazilian rice-based baby food was <29 μg kg−1. However, As-speciation revealed inorganic-As (i-As) as the main specie. The highest estimated daily intake of Cd, Pb and i-As were 1.37 (rice-based baby food); 10.39 (pasta); and 3.34 (pasta) μg d−1, respectively. Therefore, continuous food monitoring for nutritional and toxicological purpose is necessary, especially concerning these particular populations and discussions for maximum levels of non-essential elements.  相似文献   

8.
The aim of this work is to present a simple and sensitive reverse-phase liquid chromatography method for the determination and investigation of amino acids in wolfberry fruit (Lycium barbarum) after solid-phase extraction-derivatization. The method linearity, calculated for each amino acid, had a correlation coefficient higher than 0.9950, in concentrations ranged from 9.60 to 3.33 × 103 μmol L−1. The detection limits of amino acids were between 2.42 and 6.51 μmol L−1. The calculated recoveries for amino acids in wolfberry fruit were from 87.3% to 97.1% and relative standard deviations were from 2.62% to 5.22%. The investigation illustrated that each tested wolfberry fruit contained at least 16 amino acids and the main amino acids were glutamic acid, aspartic acid, proline, alanine, serine, glycine, lysine, and tyrosine. The levels of amino acid in wolfberry fruit were varying from different areas.  相似文献   

9.
Short-term bioassays based on lethal and reproductive responses of Tisbe battagliai were applied to determine responses of copepods to copper and LAS. Percentage of spawning females, fecundity (F), and total newborn production (N) for 48 and 72 h were calculated for both substances. It was observed percentage of spawning females was not affected by sublethal concentrations of both compounds. Following values were obtained: EC50(N)-48 h of 670±30 μg LAS L?1 and EC50(F)-48 h of 670±30 μg LAS L?1; and EC50(N)-72 h of 44.5±1.8 μg Cu L?1 and EC50(F)-72 h of 30.8±1.1 μg Cu L?1. Lethal effects of the two substance-types were also assessed, obtaining the LC50-24 h of 1980±160 μg LAS L?1; and LC50-48 h of 83.1±10.5 μg Cu L?1 for nauplii; and LC50-72 h of 157±25 μg Cu L?1, and LC50-72 h of 2660±270 μg LAS L?1 for adults. Fecundity and total newborn production are sensitive endpoints for determining effects of toxicants.  相似文献   

10.
This study evaluates the nutritional potential of Sarcocornia ambigua as new a source of minerals. The mineral concentrations of two different growing populations (natural occurrence and irrigated) of S. ambigua were evaluated using inductively coupled plasma mass spectrometry. In all samples, the mineral present in highest amounts was potassium (K) (19–24 μg g−1), followed by magnesium (Mg) (8.6–14 μg g−1) and then calcium (Ca) (2.6–4.0 μg g−1). In addition, in vitro bioacessibility assay demonstrated that very high fraction (65–80%) of these K and Mg (80 and 65%) of total concentration of these elements is bioacessible from S. ambigua analyzed. The trace elements vanadium (V), chromium (Cr), cobalt (Co), copper (Cu) and lithium (Li) have more than above 50% of total concentration was found bioaccessible. In all cases, mass balance was verified by carrying out the total digestion of the remaining residue and the relationship between total concentration and bioaccessibility. The data related to the concentrations and the bioaccessible fractions of the minerals provide a starting point for more complex and in-depth evaluations from the nutritional point of view, including the establishment of a recommended daily dietary intake for this plant.  相似文献   

11.
The aim of this work was to determine level of azaarenes (PANHs) in raw pork and to investigate their formation during meat frying or grilling, in particular to verify a suggestion that endogenous vitamin E might inhibit production of azaarenes. Azaarene concentration in raw pork samples from various origins ranged from 2.75 ng g−1 to 3.69 ng g−1 (2.75–2.93 ng g−1 in meat of Polish Landrace pigs, 3.00–3.69 ng g–1 in meat of hybrid Duroc × Polish Landrance pigs). PANH formation during frying of pork meat was not confirmed. On the other hand, PANHs were indeed formed during grilling; their levels ranged from 6.21 ng g−1 to 8.08 ng g–1. No inhibition influence of vitamin E on formation of PANHs on was found either in fried or grilled pork meat.  相似文献   

12.
《Vaccine》2015,33(20):2367-2378
IntroductionBenefit-risk of different anti-rabies post-exposure prophylaxis (PEP) strategies after scratches or bites from dogs with unknown rabies status is unknown in very low rabies risk settings.Design and settingA cost-effectiveness analysis in metropolitan France using a decision-tree model and input data from 2001 to 2011.PopulationA cohort of 2807 patients, based on the mean annual number of patients exposed to category CII (minor scratches) or CIII (transdermal bite) dog attacks in metropolitan France between 2001 and 2011.InterventionsFive PEP strategies: (A) no PEP for CII and CIII; (B) vaccine only for CIII; (C) vaccine for CII and CIII; (D) vaccine+ rabies immunoglobulin (RIG) only for CIII; and (E) vaccine for CII and vaccine+ RIG for CIII.Main outcomes measuresThe number of deaths related to rabies and to traffic accidents on the way to anti-rabies centers (ARC), effectiveness in terms of years of life gained by reducing rabies cases and avoiding traffic accidents, costs, and incremental cost-effectiveness ratios (ICER) associated with each strategy.ResultsStrategy E led to the fewest rabies cases (3.6 × 10−8) and the highest costs (€1,606,000) but also to 1.7 × 10−3 lethal traffic accidents. Strategy A was associated with the most rabies cases (4.8 × 10−6), but the risk of traffic accidents and costs were null; therefore, strategy A was the most effective and the least costly. The sensitivity analysis showed that, when the probability that a given dog is rabid a given day (PA) was >1.4 × 10−6, strategy D was more effective than strategy A; strategy B became cost-effective (i.e. ICER vs strategy A <3 × French Gross Domestic Product per capita) when PA was > 1.4 × 10−4.ConclusionsIn the metropolitan France's very low rabies prevalence context, PEP with rabies vaccine, administered alone or with RIG, is associated with significant and unnecessary costs and unfavourable benefit-risk ratios regardless to exposure category.  相似文献   

13.
The objective of the present study was to analyze the nutritional composition of Bombyx mori (L.) chrysalis (worm) toast. The results have revealed that this sub-product of the silk thread industry is a rich source of protein (51.1%); lipid (34.4%); essential fatty acids such as the linolenic acid (C18: 3n-3, 24.4%); zinc (244 μg g−1) and potassium (4.77 mg g−1). The composition of this sub-product shows good polyunsaturated/saturated (0.99) and n-6/n-3 (0.30) fatty acids ratios. Chrysalis (worm) toast could balance human nutrition and could be used as an alternative dietary supplement of proteins and fatty acids, or could be used as animal feed.  相似文献   

14.
A simple and rapid voltammetric method based on the use of disposable screen-printed electrodes is proposed for the determination of vitamin B6. The influence of the pH on the voltammetric response was analyzed. Estimation of the linear range (2.0 × 10−6/7.2 × 10−5 M), calibration function, limit of detection (1.5 × 10−6 M) and reproducibility was performed along with the determination of possible interferences from species present in real samples. The proposed analytical system was successfully applied for the determination of pyridoxine in multivitamin supplements, energy drinks and breakfast cereals by using the standard addition method.  相似文献   

15.
In this paper, microwave-accelerated dispersive liquid–liquid microextraction has been developed for the extraction/preconcentration of some organophosphorus pesticides from aqueous samples prior to their analysis by gas chromatography–flame ionization detection. In this method, temperature of a high volume of aqueous sample is elevated by a microwave oven and then a mixture of extraction and disperser solvents is rapidly injected into the aqueous phase. After cooling to room temperature, the phase separation is accelerated by centrifuging. The main experimental factors affecting performance of the method including type and volume of the extraction and disperser solvents, temperature, pH, and salt addition were investigated and optimized. Under the optimum extraction conditions, the method resulted in low limits of detection and quantification within the ranges of 0.65–1.3 and 2.2–4.5 μg L−1, respectively. Relative standard deviations were in the range of 2–7% (C = 40 or 100 μg L−1) for intra-day (n = 6) and inter-day (n = 4) precisions. Finally, the proposed method was successfully applied to analysis of the target analytes in surface water and well water and fruit juice samples; diazinon was determined at μg L−1 level in apple juice.  相似文献   

16.
K. pneumoniae isolates carrying blaKPC-3 gene were collected to perform Bayesian phylogenetic and selective pressure analysis and to apply homology modeling to the KPC-3 protein. A dataset of 44 blakpc-3 gene sequences from clinical isolates of K. pneumoniae was used for Bayesian phylogenetic, selective pressure analysis and homology modeling. The mean evolutionary rate for blakpc-3 gene was 2.67 × 10 3 substitution/site/year (95% HPD: 3.4 × 10 4–5.59 × 103). The root of the Bayesian tree dated back to the year 2011 (95% HPD: 2007–2012). Two main clades (I and II) were identified. The population dynamics analysis showed an exponential growth from 2011 to 2013 and the reaching of a plateau. The phylogeographic reconstruction showed that the root of the tree had a probable common ancestor in the general surgery ward. Selective pressure analysis revealed twelve positively selected sites. Structural analysis of KPC-3 protein predicted that the amino acid mutations are destabilizing for the protein and could alter the substrate specificity. Phylogenetic analysis and homology modeling of blaKPC-3 gene could represent a useful tool to follow KPC spread in nosocomial setting and to evidence amino acid substitutions altering the substrate specificity.  相似文献   

17.
Different honey types were collected in Croatia during 2010 and 2011: 7 multifloral orchard honeys, 7 multifloral meadow honeys, 19 black locust, 9 chestnut, 11 lime and 6 sage honeys. Elements were measured using graphite (As, Cu, Cd, Pb, Se) and flame atomic absorption spectrometer (Ca, Fe, K, Mg, Na, Zn) and by mercury analyser (Hg). Significant differences in Ca, Fe, K, Mg, Zn, As and Hg levels were observed between honey types. In chestnut honey were determined (K, Ca, Mg: mg kg−1; Hg, Ad, Cd: μg kg−1): the highest concentrations of K 2824.4, Ca 486.7, Mg 59.1 and Hg 2.52; the lowest of As 24.1 and Cd 2.52. Lime honey has been shown the highest content of Cu (20.6 mg kg−1), Zn (6.78 mg kg−1), Cd (2.14 μg kg−1) and Pb (810.3 μg kg−1). The lowest levels of following elements were determined in black locust honey (Fe, K, Mg: mg kg−1; Hg: μg kg−1): Fe 2.77, K 304.7, Mg 8.02 and Hg 0.82. Sage honey had the lowest Ca and Na content (173.9 and 31.8 mg kg−1). Among the multifloral honeys, the following was determined (Fe, Na, Cu: mg kg−1; As, Pb: μg kg−1): orchard honey – highest of Fe 5.17 and As 276.1, lowest Pb 301; meadow honey – highest Na 36.1, lowest Cu 4.38. The average Ca, Cu and Pb levels found in multifloral honey types were much higher than those reported in other European countries. Calcium levels in lime, chestnut and black locust were higher than those from other countries.  相似文献   

18.
Scattering signals and partial overlapping of target peaks usually appear in fluorescence determination. In this study, the improved wavelet moment method was proposed and applied to the quantitative determination of multiple target components in real B-vitamins complex tablets based on three-dimensional (3D) fluorescence spectra. The correlation coefficients (R) were more than 0.9939, and the correlation coefficients of leave-one-out cross-validation (RLOO-cv) were more than 0.9376. The inter-day and intra-day variations were less than 5.8% and 6.1%, respectively. The recovery ranged from 97.6% to 109.4%. The limits of detection (LODs) and quantification (LOQs) were less than 0.07 μg mL−1 and 0.13 μg mL−1, respectively. All the statistical parameters indicated that the method was stable and reliable. The application to the practical samples confirmed that wavelet moment method effectively extracted the features of target components in 3D spectra and the proposed method could be applied to the analyses of food or other complex samples.  相似文献   

19.
A novel headspace solvent microextraction (HSME) method for the extraction of trace amounts of 2,4-dimethylaniline (2,4-DMA), produced after hydrolysis of amitraz, is presented. The hydrolysis reaction and HSME were carried out in a single step, and then the preconcentrated 2,4-DMA was analyzed gas chromatographically using a thermionic specific detector (TSD). Different parameters affecting the HSME procedure including the type of solvent, headspace volume, stirring rate, Na2SO4 content, solution and microdrop temperature, drop volume and extraction time were studied and optimized. The optimized conditions were 25 min solution equilibrium time, 10 min solvent equilibrium time, 5 mL headspace volume, 600 rpm stirring rate, 15% Na2SO4, solution temperature 60 °C, microdrop temperature 4 °C and microdrop volume 3 μL. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 10 and 30 ngamitraz g−1honey, respectively, and the dynamic linear range was from 0.03 to 10 μgamitraz g−1honey. Finally, the proposed method was applied to the quantification of amitraz in spiked honey samples. Because of performing hydrolysis and extraction processes in a single step, the method provided a rapid, simple and sensitive approach to analysis of amitraz.  相似文献   

20.
The anthocyanin composition was analysed in fig fruit (Ficus carica L.) from five different varieties (Colar, Cuello de Dama (green), Cuello de Dama (dark purple), Granilla and Bursa Siyahi). Fifteen anthocyanin pigments were detected, most of them containing cyanidin (Cy) as aglycone; some pelargonidin (Pg) derivatives were also found. Rutinose and glucose were present as substituting sugars, as well as acylation with malonic acid. Minor levels of peonidin 3-rutinose (Pn 3-rutinoside) in the pulp were also detected. Other noticeable aspects in the pigment composition of the fig were the detection of anthocyanidin-derived pigments, namely 5-carboxypyranocyanidin-3-rutinoside, a cyanidin 3-rutinose dimer and five condensed pigments containing C–C linked anthocyanins (Cy and Pg) and flavanol (catechin and epicatechin) residues. Total anthocyanin content in the skin ranged between 32 and 97 μg g−1 and between 1.5 and 15 μg g−1 in the pulp. The main anthocyanin in both parts of the fruit was Cy 3-rutinoside (48–81% in skin and 68–79% in pulp) usually followed by Cy 3-glucoside (5–18% in skin and 10–15% in pulp). Malonyl derivatives were more abundant in the skin (1.2–6.5%) than in the pulp (1.0–2.6%).  相似文献   

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