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1.
《Analytical letters》2012,45(11):1952-1964
The distributions of cadmium and lead in marine sediments, surrounding soil, stones, and atmospheric particulate matter were determined at different locations in Split, Croatia. The determination of cadmium and lead was performed by flame atomic absorption spectrometry whereas atmospheric particulate matter samples were analyzed by inductively coupled plasma–optical emission spectrometry. Cadmium concentrations in the stones and soil were between 0.2 to 0.6 µg g?1 and 0.2 to 0.9 µg g?1. The concentration in the atmospheric particulate matter were <0.2 µg m?2 d?1(detection limit) to 1.4 µg m?2 d?1. Lead concentrations in marine sediments, stones, soil, and atmospheric particulate matter ranged from 31.2 to 144.4 µg g?1, 9.3 to 29.4 µg g?1, 11.3 to 66.1 µg g?1, and 0.5 to 241.4 µg m?2 d?1, respectively. The relationship between determined parameters was established using principal component analysis and the results are in agreement with the assumption that anthropogenic sources play important roles for lead and cadmium distribution.  相似文献   

2.
An effective method utilising pressurised fluid extraction (PFE) to simultaneously extract polycyclic aromatic hydrocarbons (PAHs) and their polar oxidation products from atmospheric particulate matter (PM) is presented. The PFE method is advantageous over the traditional Soxhlet extraction due to its lower solvent consumption (9 mL compared to 90 mL) and shorter extraction time (15 min versus 18 h). Seventy compounds including PAHs and polar PAH oxidation products containing carbonyl (oxy-PAHs), hydroxyl (hydroxy-PAHs), and carboxylic acid (carboxy-PAHs) groups were targeted in the extraction of two different PM matrices: wood smoke (WS) and diesel exhaust (DE) PM. The PFE method was optimised and then compared to Soxhlet extraction for both PM matrices. The overall amounts of PAHs and their derivatives extracted from WS PM were slightly higher for the optimised PFE method (1849 ± 21 and 1863 ± 25 µg g?1 with dichloromethane (DCM) and methanol (MeOH), respectively) than those obtained with Soxhlet extraction (1726 ± 33 and 1769 ± 22 µg g?1 with DCM and MeOH, respectively). For DE PM (standard reference material (SRM) 2975) the overall amounts extracted by both methods were similar (average of 165 ± 6 µg g?1), agreeing with previously published values. The detailed evaluation of extraction efficiencies for WS PM showed similar amounts for unfunctionalised PAHs (1100 µg g?1) for both methods and solvents. For DE PM the mass yields for PAHs using PFE with DCM (62 ± 1 µg g?1) were the highest and nearly 20% higher than those obtained with MeOH (53 ± 2 µg g?1). The total mass yields of carboxy and hydroxy-PAHs from WS PM were also similar (412 ± 18 and 407 ± 11 µg g?1) for PFE and Soxhlet with MeOH, and higher than when DCM was used (371 ± 5 and 379 ± 12 µg g?1 for PFE and Soxhlet, respectively). For both matrices, the PFE yields for oxy-PAHs were higher than those obtained with Soxhlet.  相似文献   

3.
《Analytical letters》2012,45(8):1400-1408
There are three major production bases of navel oranges in China, including Southern Jiangxi Province, Southern Hunan Province, and the Three Gorges District of the Yangtze River. Southern Jiangxi and Southern Hunan are also famous for rare earth elements that are ionic, making them easily passed from soil to plants and fruits. To test the relative enrichment of rare earth elements in navel oranges from these production sites, ICP-MS analysis was performed following a microwave digestion procedure. The concentrations of La, Ce, Pr, and Nd in navel orange peels from Southern Jiangxi and Southern Hunan (1.26–1.86 µg g?1) were much higher than results from the Three Gorges (0.23–0.46 µg g?1). Moreover, yttrium is relatively enriched (0.25–0.29 µg g?1) in navel orange peels from Southern Jiangxi at concentrations almost twice that from Southern Hunan (0.15 µg g?1). The various concentrations and distribution of rare earth elements offers the possibility of traceability and authentication of navel oranges. Meanwhile, navel orange peels from Southern Jiangxi posed no risk in consumption, based on the maximum limit level (≤0.7 µg g?1, wet weight) of rare earth elements in food issued in China (GB 2762-2005).  相似文献   

4.
《Analytical letters》2012,45(17):2792-2807
Ultrasensitive Square Wave Anodic Stripping Voltammetry is used for the first time for the systematic determination of Cd, Pb, and Cu in siliceous spicules of marine sponges; the procedure is performed directly in hydrofluoric acid solution, according to a procedure previously established in our laboratory, with the aim of demonstrating the feasibility of such measurements and to improve knowledge of heavy metal distribution in Porifera. The following Demospongiae species are considered: Sphaerotylus antarcticus, Haliclona sp., Kirkpatrickia coulmani, and Inflatella belli from the Ross Sea, Antarctica, and Petrosia ficiformis from the Mediterranean Sea, Italy. The method shows a good accuracy; the analytical variability is approximately ±10% for all the metals studied and for all the measurements performed, showing a good repeatability of the method in consideration of low metal concentrations (order of tenths of µg g?1 dry weight, i.e., of hundreds of ng L?1 in the HF solution). In particular, the concentrations of heavy metals in the body of the sponge vary in the range 0.038–0.93 µg g?1 dry weight (d.w.) for Cd, 0.024–0.52 µg g?1 d.w. for Pb, and 0.32–1.3 µg g?1 d.w. for Cu. Similar ranges of concentration were recorded in the oscula of S. antarcticus and I. belli. Heavy metal concentration in the spicules can vary within and between specimens and, in particular, siliceous spicules of Antarctic sponges show higher concentrations of Cd and Pb and lower concentrations of Cu than those from the Mediterranean.  相似文献   

5.
Abstract

The objective of this study was to examine the bioactive flavonoids and carotenoids concentration in fifteen south Indian spice and two tree nut species using high performance liquid chromatography (HPLC). Among four flavonoids, catechin concentration was the highest in all spices and nuts and ranged between 97.1 and 1745.4 µg g?1. Quercetin concentration was the greatest in cinnamon, followed by garlic and cumin and ranged from 0.4 to 65 µg g?1 in other spices and nuts. Lutein concentration ranged from 0.1 to 102.8 µg g?1. Of the spices and nuts studied, β-carotene concentration was highest in coriander leaves (74.7 µg g?1), followed by red pepper (12.5 µg g?1) and curry leaves (8.5 µg g?1). This research shows that consumption of south Indian spices and nuts could substantially benefit consumers living in regions experiencing Vitamin A and other micronutrient deficiencies.  相似文献   

6.
《Analytical letters》2012,45(10):1758-1768
This paper reports the determination of the mineral composition of watercress (Nasturtium officinale Cruciferae, Brassicaceae), grown in soils from three cities in the Bahia State of Brazil, and in a fourth city where plants were grown in a hydroponic system. The sampling was carried out during the summer and winter. Analyses were performed with inductively coupled plasma optical emission spectrometry (ICP OES), and the accuracy was confirmed with a certified reference material of apple leaves.

Principal component analysis (PCA) and hierarchical cluster analysis (HCA) revealed different mineral compositions of the samples collected in the summer and winter.

Samples collected in the summer had a higher concentration of the nutrients iron, calcium, and magnesium, and the samples collected in the winter had a higher concentration of manganese and copper. The average contents of the samples (expressed as wet weight) were 2.50 and 3.03 mg g?1 for calcium, 0.37 and 0.86 mg g?1 for magnesium, 8.68 and 10.84 µg g?1 for iron, 8.42 and 8.47 µg g?1 for zinc, 0.61 and 0.47 µg g?1 for copper, and 7.78 and 5.03 µg g?1 for manganese for summer and winter, respectively. These results are in agreement with values previously reported in the literature. Samples collected from the hydroponic system in the winter had a lower concentration of all nutrients.  相似文献   

7.
《Analytical letters》2012,45(1):48-59
Parthenium hysterophorus L., is an obnoxious weed known for its environmental health hazards and medicinal uses. These characteristics are due to presence of sesquiterpene lactones and organic acids; therefore a rapid and sensitive analytical procedure using HPLC-PDA-MS-MS was developed and optimized for separation, identification, and quantification of parthenin and six organic acids. Separation and characterization of compounds was achieved on a RP-C18 column with 1% acetic acid in water (A) and acetonitrile (B) as a mobile phase at a flow rate of 0.6 mL min?1 and by matching their UV and mass spectra with reference compounds. Six organic acids (ferulic acid, 0.1 mg g?1 to coumaric acid, 13.6 mg g?1) and parthenin (27.4 mg g?1) were characterized within 26 minutes of chromatographic separation in plant extract. The calibration curves are linear with correlation coefficients from 0.985 to 0.998, limit of detection and quantification ranged between 1.0 µg mL?1 (anisic acid) to 2.2 µg mL?1 (parthenin) and 2.5 µg mL?1 (coumaric acid) to 5.2 µ g mL?1 (parthenin) and recovery ranged between 90.9% to 97.3%. To the best of our knowledge this is the first report for the simultaneous separation of parthenin and organic acids. The method is applicable for screening of commercial crops, medicinal plants, and their products which might be mixed with P. hysterophorus during harvesting period.  相似文献   

8.
《Analytical letters》2012,45(17):2747-2757
Abstract

Brazilian sugarcane spirits were analyzed to elucidate similarities and dissimilarities by principal component analysis. Nine aldehydes, six alcohols, and six metal cations were identified and quantified. Isobutanol (LD 202.9 µg L?1), butiraldehyde (0.08–0.5 µg L?1), ethanol (39–47% v/v), and copper (371–6068 µg L?1) showed marked similarities, but the concentration levels of n-butanol (1.6–7.3 µg L?1), sec-butanol (LD 89 µg L?1), formaldehyde (0.1–0.74 µg L?1), valeraldehyde (0.04–0.31 µg L?1), iron (8.6–139.1 µg L?1), and magnesium (LD 1149 µg L?1) exhibited differences from samples.  相似文献   

9.
Inorganic elements are responsible for essential bodily functions, such as osmotic regulation, cardiac frequency and contractibility, blood clotting and neuromuscular excitability. The determination of inorganic elements in corporeal fluids such as blood, serum, plasma and urine is used as a monitor for a part or the whole organism; their values, then, are compared with reference interval values. In this study, the energy dispersive X-ray fluorescence spectrometry (EDXRF), applying the Fundamental Parameters method, for the determination of inorganic elements in whole blood samples from humans and laboratory animals, was used. Peripheral blood samples were collected and, before coagulation, 100 μL of sample were deposited onto Whatman No. 41 filter paper and dried, using infrared spotlight. The reference interval values for healthy Brazilian population of Na were found to be 1,788–1,826 μg g?1, of Mg 63–75 μg g?1, of P 602–676 μg g?1, of S 1,519–1,718 μg g?1, of Cl 2,743–2,867 μg g?1, of K 1,508–1,630 μg g?1, of Ca 214–228 μg g?1, of Fe 170184 μg g?1, of Cu 4–6 μg g?1 and of Zn 1–3 μg g?1. The reference interval values for golden hamster (Mesocricetus auratus) of Na were found to be 1,714–1,819 μg g?1, Mg 51–79 μg g?1, P 970–1,080 μg g?1, S 1,231–1,739 μg g?1, Cl 2,775–2,865 μg g?1, of K 1,968–2,248 μg g?1, of Ca 209–257 μg g?1, of Fe 145–267 μg g?1, of Cu 4–6 μg g?1 and of Zn 3–5 μg g?1. A comparative study between EDXRF and instrumental neutron activation analysis data was carried out and the results for both techniques are statistically equal (α = 0.05). The results contribute for the establishment of reference interval values for Na, Mg, P, S, Cl, K, Ca, Cu and Zn in the healthy Brazilian population and the referred laboratory animal species.  相似文献   

10.
《Analytical letters》2012,45(1-3):271-283
A flow injection system is proposed for catalytic kinetic spectrophotometric determination of trace iron(II + III). The involved reaction is based on the catalytic effect of iron(III) on oxidation reaction of xylenol orange by potassium bromate to form a blue-violet complex. Iron(II) is also determined, being oxidized to iron(III) by potassium bromate. The calibration graph is linear in the range of 0.02–10.0 µg l?1 and 10.0–1100 µg l?1. The relative standard deviation is 1.5% for 4.0 µg l?1 iron(III) and 2.3% for 60.0µg l?1 iron(III) (n = 11). The presented system was applied successfully to the determination of iron in natural waters.  相似文献   

11.
《Analytical letters》2012,45(15):2508-2521
Porous polyaniline coatings doped with different counter ions were electrodeposited on the surface of stainless steel wires using controlled potentiostatic coulometry. Prior to electropolymerization, the stainless steel wires were chemically etched to improve subsequent immobilization of the polyaniline coatings on the substrate and to increase the effective surface area. Porous polyaniline coatings doped with sulfate, nitrate, and perchlorate counter ions were employed for solid-phase microextraction (SPME) of 2-chlorophenol, 2,4-dichlorophenol, triclosan, and 2,4-dichlorophenoxyacetic acid coupled to high-performance liquid chromatography. The results demonstrated that the perchlorate doped polyaniline coating exhibited the highest extraction efficiency for 2-chlorophenol, 2,4-dichlorophenol, and triclosan at pH 5.0, indicating that the extraction capability was modified by introducing different counter ions into the coatings. As a result, the perchlorate doped polyaniline coated fiber was further used for the optimization of extraction condition s . The method provided linear dynamic ranges over 2 to 4 orders of magnitude. The limits of detection were 0.006 µg · L?1, 0.005 µg · L?1, and 0.040 µg · L?1 for 2-chlorophenol, 2,4-dichlorophenol, and triclosan, respectively. The precision expressed as the relative standard deviation ranged from 2.20% to 5.04% for spiked water at 10 µg · L ?1 (n = 5) and the fiber to fiber reproducibility was between 3.27% and 5.91% (n = 5). The method was successfully applied to the determination of chlorophenolics in real water samples. The recoveries of chlorophenolics in spiked water at 5.0 µg · L?1 were between 99.60% and 108.7% with relative standard deviations between 3.24% and 5.47%.  相似文献   

12.
《Analytical letters》2012,45(10):1842-1852
A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic Fluorescence spectrometers as detectors was developed to analyze mercury, arsenic, and barium from herbarium mount paper originating from the herbarium collection of the National Museum of Wales. The variables influencing extraction were optimized by a multivariate approach. The optimal conditions were found to be 1% HNO3 extractant solution used at a flow rate of 1 mL min?1. The duty cycle and amplitude of the ultrasonic probe was found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance between the probe and the top face of the extraction chamber was found to be 0 cm. Under these conditions the time required for complete extraction of the three analytes was 25 min. Cold vapor and hydride generation coupled to atomic fluorescence spectrometry was utilized to determine mercury and arsenic, respectively. The chemical and instrumental conditions were optimized to provide detection limits of 0.01 ng g?1 and 1.25 ng g?1 for mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic absorption spectrometry, with a detection limit of 25 ng g?1. By using 0.5 g of sample, the concentrations of the target analytes varied for the different types of paper and ranged between 0.4–2.55 µg g?1 for Ba, 0.035–10.47 µg g?1 for As, and 0.0046–2.37 µg g?1 for Hg.  相似文献   

13.
In the present study, multiwalled carbon nanotubes (MWCNTs) as solid phase extraction sorbent were developed for preconcentration of arsenic(V) species prior to graphite furnace atomic absorption spectrometry (GFAAS) determination. Arsenic(V) was selectively sorbed on the packed column with MWCNTs within a pH 9.5 in the presence of 2-(5-bromo-2-pyridylazo)-5-diethyl amino phenol (5-Br-PADAP). The adsorbed species was then desorbed with 1 mL of 2.0 M HNO3. Experimental parameters including pH, sample volume and flow rate, type, volume and concentration of eluent that influence the recovery of the arsenic(V) species were optimised. Under the optimised conditions, the calibration curve was linear in the range of 0.2–10.0 µg L?1 with detection limit of 0.016 µg L?1. The relative standard deviations (RSD) for seven replicate determinations at 1.0 µg L?1 level of arsenic was 6.69%. The proposed method was successfully applied to the determination of arsenic in water samples and certified reference material (NIST RSM 1643e).  相似文献   

14.
Antioxidant activities of eight indigenous cyanobacterial strains belonging to the genera Oscillatoria, Chroococcidiopsis, Leptolyngbya, Calothrix, Nostoc and Phormidium were studied in relation with their phenolic and flavonoid contents, ranging 3.9–12.6 mg GAE g?1 and 1.7–3.44 mg RE g?1. The highest activities were shown by Leptolyngbya sp. SI-SM (EC50 = 63.45 and 67.49 μg mL?1) and Calothrix sp. SI-SV (EC50 = 65.79 and 69.38 μg mL?1) calculated with ABTS and DPPH assays. Significant negative correlations were seen between total phenolic and flavonoid contents and the antioxidant activities in terms of EC50 values. Furthermore, HPLC detected 15 phenolic compounds with total concentrations ranging from 277.3 to 829.7 μg g?1. The prevalent compounds in most of the strains were rutin, tannic acid, orcinol, phloroglucinol and protocatechuic acid. Cyanobacterial strains showed high potential as a good source of phenolic compounds with potent antioxidative potential which could be beneficial for food, cosmetic and pharmaceutical industries.  相似文献   

15.
《Analytical letters》2012,45(5):837-852
Abstract

A simple, rapid, sensitive, and reproducible procedure for assaying norfloxacin (NOR), ciprofloxacin (CIP), and ofloxacin (OFL) was investigated. The procedure is based on the reaction of selected drugs with Sudan II (I), Congo red (II), and Gentian violet (III) in universal buffer to give soluble ion‐pair complexes. The effects of various parameters have been studied. Beer's law plots were obeyed in the concentration ranges 0.5–11 µg ml?1, whereas Ringbom optimum ranges were 0.7–9.5 µg ml?1. The apparent molar absorptivity (6.4×104 L mol?1 cm?1), Sandell sensitivity (4.99 ng cm?2), detection (0.13 µg ml?1), and quantification (0.44 µg ml?1) limits were calculated. The relative standard deviation for ten determinations, for samples containing 4.0 µg ml?1, was found to be 1.40%. The influence of commonly employed excipients in the determination of the studied drugs was examined. There was no interference from degradate product results from thermal and hydrolytic treatments. The results obtained by the proposed procedure were statistically validated. The developed procedure was successfully applied to the determination of the studied drugs in dosage forms and biological fluids.  相似文献   

16.
《Analytical letters》2012,45(2):343-355
A new analytical procedure for the determination of five organotin compounds in several matrix wine samples is reported. The organotin compounds were extracted by microwave-assisted extraction with n-hexane. Extraction conditions, such as volume of n-hexane required, extraction temperature, and extraction time, were investigated and optimized by an orthogonal array experimental design. The determination of organotin compounds in the final extracts was carried out by liquid chromatography–inductively coupled plasma mass spectrometry. The procedure showed limits of detection between 0.029–0.049 µg · L?1. The linearity was in the range of 0.5 to 100 µg · L?1. The precision expressed as relative standard deviation (RSD) was below 9.43%. The developed method was successfully employed to analyze different matrix wine samples, and some analytes were detected at the level of 0.053 to 1.14 µg · L?1.  相似文献   

17.
《Analytical letters》2012,45(5):856-867
A novel flow injection system incorporating a micro-column packed with carbon nanotubes (CNTs) as an adsorbent has been applied to the on-line preconcentration of trace silver with detection by flame atomic absorption spectrometry. Silver is first chelated by dithizone (H2Dz), then retained on the CNTs surface and afterward quantitatively eluted by methanol. Influencing parameters, including the concentration of reaction reagent, enrichment variables, and elution variables were investigated. The adsorption mechanisms of Ag-H2Dz chelate retained onto the CNTs surface have also been studied. By loading 6.9 mL sample solution, a linear calibration graph is obtained within the range of 3–120 µg L?1 with R of 0.9996, and a detection limit (3σ) of 0.8 µg L?1 is achieved, along with a precision of 1.6% R.S.D. at the 30 µg L?1 level (n = 7). The dynamic sorption capacity of CNTs for silver is 122 mg g?1. The procedure is demonstrated by measurement of spike recovery in a series of water samples, giving rise to spike recoveries in the range of 96.8–99.7%.  相似文献   

18.
《Analytical letters》2012,45(13):2075-2088
For the first time, a simple method for magnetic stirring-assisted dispersive suspended microextraction has been developed for the determination of three fungicides (azoxystrobin, diethofencarb, and pyrimethanil) in water and wine samples. The method is based on the solidification of a floating organic droplet coupled with high performance liquid chromatography. In the proposed method, the low toxicity solvent 1-dodecanol was used as the extractant. Both the extraction and phase separation process were performed with magnetic stirring. No centrifugation step was involved. After separating the two phases, the extraction solvent droplet was easily collected through solidification at lower temperature. Important parameters such as the kind and volume of organic extraction solvent, extraction and restoration speed, extraction and restoration time, and salt concentration were optimized. Under the optimal conditions, the limits of detection for the analytes varied from 0.14 to 0.26 µg L?1. The enrichment factors ranged from 125–200. The linearity ranges were 1–2000 µg L?1, yielding correlation coefficients (r) higher than 0.9990. The relative standard deviation (n = 6) at two spiked level of 0.2 µg mL?1 and 4 µg L?1 varied between 2.2% and 7.8%. Finally, the developed technique was successfully applied to determine target fungicides in real water and wine samples, where the obtained recoveries ranged from 83.8–105.3%  相似文献   

19.
A dynamic branch enclosure system was used to measure emission rates of biogenic volatile organic compounds (BVOCs) from two common European tree species: Fraxinus excelsior and Quercus robur under ambient conditions in Flanders (Belgium). Both tree species were studied for seasonal variability of BVOC emission rates under natural biotic stress (infestations). Emissions were normalized at standard conditions of temperature and photosynthetic active radiation (PAR) (30°C and 1000?µmol?m?2?s?1, respectively). Emission rates from Fraxinus excelsior were highest in May (9.56?µg?gDW ?1?h?1) and lowest in October (1.17?µg?gDW ?1?h?1). This tree species emitted (Z)-β-ocimene, (E)-β-ocimene and α-farnesene during the entire measurement period and additionally isoprene only in May. Quercus robur showed isoprene emission variations according to the seasonal cycle with rates of 30, 106 and 29?µg?gDW ?1?h?1 in May, August and October, respectively. Apart from isoprene, (E)-β-ocimene and β-caryophyllene were emitted through the entire experimental period.  相似文献   

20.
The arsenic species present in samples of the crayfish Procambarus clarkii caught in the area affected by the toxic mine‐tailing spill at Aznalcóllar (Seville, Southern Spain) were analyzed. The total arsenic contents ranged between 1.2 and 8.5 µg g?1 dry mass (DM). With regard to the different species of arsenic, the highest concentrations were for inorganic arsenic (0.34–5.4 µg g?1 DM), whereas arsenobetaine, unlike the situation found in marine fish products, was not the major arsenic species (0.16 ± 0.09 µg g?1 DM). Smaller concentrations were found of arsenosugars 1a (0.18 ± 0.11 µg g?1 DM), 1b (0.077 ± 0.049 µg g?1 DM), 1c (0.080 ± 0.089 µg g?1 DM), and 1d (0.14 ± 0.13 µg g?1 DM). The presence of two unknown arsenic species was revealed (U1: 0.058 ± 0.058 µg g?1 DM; U2: 0.12 ± 0.12 µg g?1 DM). No significant differences were seen with respect to the total arsenic contents between the sexes. However, significant differences in the total arsenic contents were revealed between the area affected by the spill and the area not affected, the contents being greater in the affected area. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

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