首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Trace element levels in honeys from different regions of Turkey   总被引:1,自引:0,他引:1  
A survey of 25 honey samples from different botanical origin, collected all over the Turkey was conducted to assess their trace element contents. The aim of this study was to determine the levels of cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr), zinc (Zn), aluminium (Al) and selenium (Se) in honey samples from different regions of Turkey. Trace element contents were determined by a flame and graphite furnace atomic absorption spectrometry technique after dry-ashing, microwave digestion and wet-digestion. The accuracy of the method was corrected by the standard reference material, NIST-SRM 1515 Apple leaves. The contents of trace elements in honey samples were in the range of 0.23–2.41 μg g−1, 0.32–4.56 μg g−1, 1.1–12.7 μg g−1, 1.8–10.2 μg g−1, 8.4–105.8 μg kg−1, 2.6–29.9 μg kg−1, 2.4–37.9 μg kg−1, 0.9–17.9 μg kg−1, 83–325 μg kg−1 and 38–113 μg kg−1 for Cu, Mn, Zn, Fe, Pb, Ni, Cr, Cd, Al and Se, respectively. Iron was the most abundant element while cadmium was the lowest element in the Turkish honeys surveyed. The results showed that trace element concentrations in the honeys from different regions were generally correlated with the degree of trace element contamination of the environment.  相似文献   

2.
In this work, the capability of different chemical modifiers (Pd, Pd/Mg(NO3)2, Pd/NH4NO3, NH4H2PO4, NH4H2PO4/Mg(NO3)2) to eliminate the matrix effects in the direct determination of Cd, Cu and Zn in food-stuffs by solid sampling-electrothermal atomic absorption spectrometry was compared. The alternative analytical lines were used for determination of Cu (327.4 nm) and Zn (307.6 nm) in order to allow the introduction of reasonably high sample mass into the furnace. Mixed modifiers containing palladium were useful to eliminate the matrix effect in Cd determination. For Cu and Zn determination the application of Pd shows satisfactory analytical performance. In the determinations of Cd and Zn the phosphate containing modifiers shows elimination of matrix effects only when applying them to a partially pyrolysed sample (at 400 °C). The achievable limits of detection for Cd, Cu and Zn in solid samples were 0.279 ng g−1; 0.020 μg g−1 and 2.04 μg g−1, respectively.  相似文献   

3.
Offal of bovine, ovine and porcine are able to accumulate potentially toxic heavy metals, such as Cd and Pb, posing a risk for human health. For this reason, the Commission Regulation no. 466/2001 provided the maximum admitted levels for these metals in this kind of matrix (Cd, 500 ng g−1 in all kinds of offal; Pb, 500 ng g−1 in liver and 1000 ng g−1 in kidney). A method based on sector field inductively coupled plasma mass spectrometry for Cd and Pb quantification in calf liver was developed and further applied to offal of different animals. The uncertainty of measurements was calculated according to the Eurachem/Citac Guide. The method LoDs and LoQs were 3.5 and 11 ng g−1 for Cd, and 2.0 and 6.0 ng g−1 for Pb. The repeatability and the intra-laboratory reproducibility showed relative standard deviations equal to 2.25% and 1.99% for Cd and 1.49% and 6.55% for Pb. Relative expanded uncertainties at the mean value in calf liver were 4.74% for Cd and 13.8% for Pb. In Italian offal the following concentration intervals were found (in ng g−1): (i) Cd: calf, from <3.5 in spleen and lung to 96.4 in kidney; lamb, <3.5 in all offal; pig, 114 in liver and (ii) Pb: calf, from 4.03 in lung to 31.8 in liver; lamb, from 4.71 in heart to 279 in liver; pig, 9.19 in liver.  相似文献   

4.
The solid phase extraction method developed using N-benzoyl-N-phenylhydroxylamine as a chelating reagent and Amberlite XAD-1180 as an adsorbent was used for the determination of Cu(II) and Fe(III) in various food samples by flame atomic absorption spectrometry. The samples were digested by using nitric acid and hydrogen peroxide. The Cu concentrations ranged from 1.01 to 5.81 μg g−1 in cereals, from 0.40 to 9.67 μg g−1 in vegetable and fruits and from 0.37 to 0.70 μg g−1 in infusions while the Fe concentrations ranged from 7.48 to 34.3 μg g−1 in cereals, from 5.74 to 260 μg g−1 in vegetable and fruits, from 1.63 to 5.12 μg g−1 in infusions and from 0.24 to 1.56 mg L−1 in beverage samples. The Cu and Fe concentrations found were compared with the results obtained from the other food studies in the world.  相似文献   

5.
A total of 157 raw milk samples were collected from tankers arriving at processing facilities from rural areas in northern and southern regions of Croatia during 2009 and 2010. Concentrations of As, Cd, Cu, Hg and Pb in the samples were analysed by graphite furnace-atomic absorption spectroscopy. Mean Pb concentrations in northern and southern regions were 58.7 and 36.2 μg l−1, respectively, and both exceeded the maximum recommended level. Arsenic concentrations ranged from 1 to 283 μg l−1 in the southern and to 1019 μg l−1 in the northern regions. Mean Cd and Hg levels were: 1.76 and 1.59 in the northern and 3.4 and 7.1 μg l−1 in the southern region. Significantly higher Cd and Hg levels were observed in the southern than in the northern region (p < 0.001, both). Similar mean Cu levels were found in both regions: 931.9 in the north and 848.4 μg l−1 in the south. The results indicate that particular attention should be paid to Pb residues. In future studies, a greater number of milk samples and grass samples from pastures from different regions of Croatia should be controlled to confirm the absence of possible toxicological risks.  相似文献   

6.
Palladium plus magnesium nitrates with and without Ir, Ru and W were evaluated for the simultaneous determination of As, Cu and Pb in cachaça by graphite furnace atomic absorption spectrometry. For 20 μL of sample, 5 μL Pd(NO3)2 and 3 μL Mg(NO3)2 dispensed together onto the Ir-coated platform of the THGA, analytical curves in the 0–30.0 μg L−1 As, 0–1.50 mg L−1 Cu and 0–60.0 μg L−1 Pb were built up and typical linear correlation coefficients were always better than 0.999. The limit of detection was 1.30 μg L−1 As, 140 μg L−1 Cu and 0.90 μg L−1 Pb. As, Cu and Pb contents in 10 cachaça samples agreed with those obtained by ICP-MS. Recoveries of spiked samples varied from 96% to 106% (As), 97% to 112% (Cu) and 92% to 108% (Pb). The relative standard deviation (n = 12) was typically 2.7%, 3.3% and 1.9%.  相似文献   

7.
The concentrations of As, Cd, Cu, Hg and Pb were determined in 54 multi-floral honey samples collected from five regions of Croatia during 2009 and 2010. Element contents decreased in the following order: Cu > Pb > As > Hg > Cd. Significant differences in lead and copper levels were observed between regions. Mean levels of elements (μg kg−1) in all honey samples measured were: 19.7 for As, 1.51 for Cd, 1074 for Cu, 2.72 for Hg and 65.2 for Pb. Copper and lead were the most abundant elements in the Centre region, with range and mean contents of 108–41,271 and 3232 μg kg−1 and 22.0–440 and 131 μg kg−1, respectively. The highest element contents were: As 23.8 μg kg−1 in the South region, Cd 2.11 μg kg−1 in the Southwest region and Hg 2.63 μg kg−1 in the Northeast region. The finding that lead contents in Croatian honey were higher than most reported lead levels in honey from other European countries is of particular concern. These indicate that attention must be focused on setting positions for honey production hives in areas distant from highways and railways.  相似文献   

8.
A non-chromatographic speciation method has been developed for the determination of inorganic arsenic in cultivated and wild mushroom samples from different origins. The ultrasound-assisted extraction of the toxic arsenic species As (III) and As (V) was performed for 10 min with 1 mol l−1 H3PO4 and 0.1% (m/v) Triton X-100. After phase separation the residue was washed with 0.1% (w/v) EDTA and centrifuged. As (III) and As (V) were determined by hydride generation atomic fluorescence spectrometry. Speciation was made using proportional equations corresponding to two different measurement conditions, (i) directly feeding sample extracts diluted with HCl and (ii) after reduction with KI and ascorbic acid for 30 min. The limits of detection of the method were 6.3 and 5.0 ng g−1 for As (III) and As (V), respectively. Recovery percentages varied between 91% and 108% for As (III) and from 90% to 109% for As (V) indicating that As species interconversion was avoided. As (III) concentrations from 264 to 81 μg g−1 and As (V) concentrations from 246 to 59 μg g−1 were found in Spanish cultivated mushrooms. For Chinese wild mushrooms As (III) varied between 624 and 117 μg g−1 and As (V) from 380 to less than 5 μg g−1. The accuracy of the method was checked by the determination of total As (from the sum of As (III) and As (V)) in a tomato leaves reference sample, with good agreement with the certified value.  相似文献   

9.
Arsenic removal from rice by washing and cooking with water   总被引:1,自引:0,他引:1  
Two Hungarian and one Chinese rice samples were selected in order to establish the extractable arsenic content by washing and cooking in water in a ratio of 6:1, water:rice (cm3:g) by inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). Total arsenic concentration of the Zhenshan 97, Risabell and Ko?röstáj-333 samples were 171.3 ± 7.1 ng g−1, 116.0 ± 3.7 ng g−1 and 139.0 ± 6.1 ng g−1, respectively, which did not exceed the toxic limits established for As in Hungary (0.3 μg g−1) or in China (0.7 μg g−1). The predominant chemical form of As in the raw rice samples determined by on-line high performance liquid chromatography and ICP-MS was arsenite. Moreover, enzymatic hydrolysis with α-amylase + protease and microprobe focused sonication proved that arsenite could be removed in the highest extent by washing and cooking, meanwhile the main As form remaining in the cooked rice was As(V). Thus, it is recommended to prepare rice-containing dishes in abundant water, which should be discarded after washing and cooking. The results were validated with a NIST SRM 1568a.  相似文献   

10.
The synthesis and characterization of the resin Amberlite XAD-4 functionalized with 2,6-pyridinedicarboxaldehyde and its application in an on-line system for the preconcentration of cadmium, cobalt, copper, lead and manganese prior to determination using flame atomic absorption spectrometry (FAAS) is proposed. Metal ions retained on the modified resin were eluted using 1.0 mol L−1 HNO3 solution and aspirated directly to the nebulizer–burner system of a FAAS instrument using a flow injection system. Detection limits (3σ) were determined to be 0.13 μg L−1 for Cd, 0.29 μg L−1 for Cu, 0.23 μg L−1 for Mn, 0.58 μg L−1 for Co and 2.19 μg L−1 for Pb using a 10 mL of water sample loading volume. The limits of detection would be 100 times higher with units of μg kg−1 for the solid samples in which their dilution ratios as (volume/weight) were 100. Enrichment factors ranged from 23.6 to 28.9 (for Co and Mn, respectively). The proposed method was successfully applied to determination of the analytes in natural water samples and certified reference materials.  相似文献   

11.
In this paper, we prepared a highly selective imprinted polymer by a room temperature ionic liquid-mediated bulk polymerization technique, using dichlorvos as the template, methacrylic acid as the functional monomers, and trimethylolpropane trimethacrylate as the cross-linker. This functionalized material was characterized by FT-IR, static and kinetic adsorption experiments, and the results showed that this imprinted sorbent exhibited good recognition and selective ability, and offered fast kinetics for the adsorption and desorption of dichlorvos. Using the prepared material as a solid phase extraction sorbent, a novel sample pre-treatment technique that can be coupled to high-performance liquid chromatography (HPLC) had been developed for determination of trace dichlorvos residues in foods. Under the selected experimental condition, the detection limit (S/N = 3) of dichlorvos was 94.8 ng L−1, and the peak area precision (RSD) for five replicate detections of 10 μg L−1 dichlorvos was 4.41%. The blank samples of cucumber and lettuce spiked with dichlorvos at 0.005 and 0.02 μg g−1 levels were determined with recoveries ranging from 82.1% to 94.0%.  相似文献   

12.
T. Polak  B. ?lender 《LWT》2009,42(1):256-2016
The mutagenic heterocyclic amines (HAs) originate in processed proteinaceous food. The effects of ageing (non-aged - i.e. 24 h post mortem vs. 14 and 28 days post mortem kept at 1 °C) and final internal temperature on cooking (Ti, 65 and 80 °C) on the content of HAs in grilled steaks (two-plated grill, temperature of 220 °C) were studied. HA precursors (creatine, creatinine, and free amino acids) and ageing indicators, such as instrumentally measured colour values, pHultimate values and length of myofibrilar fragments on raw and cutting values on grilled beef Longissimus dorsi muscles were determined. The muscles originated from eight commercially slaughtered Simmental bulls, 19-20 months old. The content of HAs was determined by a solid-phase extraction procedure. Meat ageing is accompanied by large changes in the chemical composition and structure of muscle tissues. In general, all the ageing indicators and precursors of HAs were influenced by ageing time at the 5% level or less. Creatine content declined significantly (non-aged: 6.00 mg g−1, 14 days: 5.82 mg g−1, and 28 days: 5.55 mg g−1) and creatinine increased with days of ageing (non-aged: 0.19 mg g−1, 14 days: 0.24 mg g−1, and 28 days: 0.26 mg g−1). Higher contents of total free amino acids were determined after 14 and 28 days of storage (28.18 μmol g−1 and 37.59 μmol g−1) than in non-aged beef (19.00 μmol g−1). In this study, two HAs were determined: MeIQx (2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline) and PhIP (2—amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine). The content of HAs increases with ageing. At lower Ti, more MeIQx was formed; at higher Ti, more PhIP was formed. MeIQx was present in all samples while PhIP was found only in samples grilled to higher Ti. Samples treated to Ti = 80 °C generally contained less HAs (non-aged meat: 0.20 ng g−1, 14 days: 0.26 ng g−1, and 28 days: 0.28 ng g−1) than samples treated to Ti = 65 °C (non-aged meat: 0.19 ng g−1, 14 days: 0.36 ng g−1, and 28 days: 0.39 ng g−1) on account of MeIQx thermolability.  相似文献   

13.
Raw and pasteurised sheep’s, cow’s and goat’s milk, eggs, and beef samples from different local markets in Jordan were collected during a period of 5 months (January through May 2007) and examined for aflatoxins B1(AFB1), B2(AFB2), G1(AFG1), G2(AFG2), M1(AFM1) and M2(AFM2). The samples were analysed with high performance liquid chromatography (HPLC) using UV and Fluorescent detectors. The analysed samples of milk collected in January were found to contain 0.56 μg L−1 AFM1 and 0.1 μg L−1 AFM2 whilst, the concentration of AFM1 and AFM2 was < 0.05 μg L−1 for milk samples collected between March and May. The AFB1, AFB2, AFG1 and AFG2 contents in the analysed food products ranged from 1.10 to 8.32 μg L−1 and 0.15 to 6.36 μg L−1 in imported and fresh meat samples collected during March, respectively. The mean recovery for the HPLC method was 92% to 109% and the quantification levels were 50 ng L−1 for AFM1 and AFM2. The AFM1 was found in 10% of the tested samples with concentrations between 0.08 and 1.1 μg kg−1 and AFM2 was only found in 1.82% of the tested samples with a level of 0.1 μg kg−1. The AFM1 levels in the examined foods were higher than the maximum level of AFM1 in liquid milk set by the European Community and Codex Alimentarius of 50 ng L−1.  相似文献   

14.
In order to study the content and composition of isoflavones retained in soybean seed component, obtained each component part the embryo, cotyledon and seed coat tissues of nine different soybean varieties were analyzed for 12 isoflavones using high performance liquid chromatography with photo diode array detector (HPLC-PDA) and were compared to each other. A total average concentration of isoflavone was 2887 μg g−1 in embryo, 575 μg g−1 in whole seed, 325 μg g−1 in cotyledon, and 33 μg g−1 in seed coat. With respect to each tissue of soybean varieties, isoflavone content was highest in Geomjeongkong 2 embryo (5701 μg g−1), Geomjeongolkong whole seed (1321 μg g−1), Heugcheongkong cotyledon (951 μg g−1), and Keunolkong seed coat (56 μg g−1). Isoflavone was least present in Keunolkong embryo (341 μg g−1), Hwaeomputkong whole seed (175 μg g−1), Seonheukkong cotyledon (81 μg g−1), and Seoklyangputkong seed coat (5 μg g−1). Overall, embryo and seed coat of all nine varieties contained isoflavones at the highest and lowest level, respectively. Isoflavones accumulated in the order of malonylglycoside, glycoside, acetylglycoside, and aglycon, among which malonylglycoside was the most abundant form ranging from 66% to 79% of the total isoflavone content in all three tissues. The embryo of cooked-with-rice soybean with black seed coat appears to be the best source of isoflavone.  相似文献   

15.
An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) based on an anti-aflatoxin B1 monoclonal antibody was standardised and validated for aflatoxin screening in poultry feed samples and its performance was compared to high-performance liquid chromatography (HPLC). The ic-ELISA showed good linearity (r2 = 0.994) and detection limits of 1.25 ng g−1 for broiler feed and 1.41 ng g−1 for laying hen feed. Mean aflatoxin recovery rates by ic-ELISA were 102% (laying hen feed) and 98% (broiler feed). Aflatoxins were detected in 88.2% of the 34 broiler feed samples by ic-ELISA and HPLC at means of 10.48 ng g−1 and 8.41 ng g−1, respectively, while 92% of laying hen feed samples (n = 36) showed aflatoxin contamination at means of 20.83 and 19.75 ng g−1. The standardised ic-ELISA showed reliability and a high correlation with HPLC of 0.97 (broiler feed) and 0.98 (laying hen feed) indicating its potential for aflatoxin screening in poultry feed samples.  相似文献   

16.
In order to investigate residue levels of butylated hydroxyanisole (BHA), propyl paraben (PP) and butylated hydroxytoluene (BHT) during storage, eight-hundred kilograms of bulk peanuts were treated with the following antioxidant emulsions: BHA (1802 μg g−1), BHA–PP (1802 μg g−1 + 1802 μg g−1) M1 and BHA–PP–BHT mixtures (1802 μg g−1 + 901 μg g−1 + 2204 μg g−1) M2 and (1802 μg g−1 + 1802 μg g−1 + 2204 μg g−1) M3. Residues were determined in peanut pod and seed tissues at 1-month intervals during the storage. While the reduction levels of BHA and PP in pods at the end of the storage period ranged from 66% to 76%, BHT levels were decreased extensively (86%). Twenty-four hours after peanuts were treated, antioxidant emulsions effectively seeped into the seeds and low levels of these chemicals were detected during the assay. Residues of PP in seeds were lower (62%) than the other antioxidants. Although the doses used were higher than those approved for food-grade antioxidants in stored peanuts, the residue levels in seeds (32.8–0.02 μg g−1) did not exceed the maximum residue limits during the storage period.  相似文献   

17.
Direct determination of copper, lead and cadmium by electrothermal atomic absorption spectrometry in aniseed spirits was proposed. The methods were validated by studying quality parameters such as trueness, precision, linearity and sensitivity. Recoveries ranging between 96% and 104% were obtained from spiked samples at several concentration levels. Repeatability was less than 5% and intermediate precision was less than 8%. The procedure is fast and shows limits of detection of 0.6, 0.7 and 0.04 μg l−1 for Cu, Pb and Cd, respectively. Samples were just diluted in a water/ethanol/nitric acid mixture. Cu was present at higher concentrations, with values in the range 6–473 μg l−1. Minor levels of Pb and Cd were present with concentrations of less than 6 and 1.4 μg l−1, respectively.  相似文献   

18.
Recently, the exposure to perchlorate was emphasised as an important risk factor for human and especially newborn health. A number of studies were focused on this matter. In this study, samples of soil, vegetable (cabbage, spinach, lettuce, carrot, tomato, red cabbage), fruit (orange, mandarin, lemon, grapefruit), water, milk and fish were taken from 8 different regions of Hatay (Samanda?, K?r?khan, Reyhanl?, Amik Plain, Dörtyol, Yaylada??, Alt?nözü, Erzin). An ion chromatography system (Shimadzu C196-E039A model) was used to determine the concentrations of perchlorate in the samples. 2.5 mM Phthalic acid and 2.4 mM tris (hydroxymethyl)aminomethane solutions (pH = 4) were used as the mobile phase. A flow rate of 1.5 ml min−1 and oven temperature of 40 °C were used during the analysis. The foods had perchlorate concentrations in the range of 0.236–1.218 μg kg−1. The perchlorate concentration varied from 0.30 ± 0.01 to 0.94 ± 0.02 μg l−1 in milk samples. Perchlorate concentrations were determined to be lower in the drinking waters (0.44 ± 0.03 μg l−1) compared to irrigation waters (0.59 ± 0.03 μg l−1). Perchlorate concentrations of the fish samples were ranged from 0.38 ± 0.01 to 0.61 ± 0.01 μg kg−1.  相似文献   

19.
Using a new type of DNA and carbon nano tube (CNT) mixed paste electrode using cyclic and square wave anodic stripping voltammetric (SWASV) methods, this study presents an assay of riboflavin (RF) under optimum conditions. Results of the experiment yielded a low working concentration range of nanograms with 1–10 and 10–170 ng L−1 and 5–105 μg L−1, at an accumulation time of 80 s in a 0.1 M H3PO4 electrolyte solution. A relative standard deviation of 30 μg L−1 was observed at an accuracy level of 0.1164% (n = 15) under optimum conditions. The detection limit (S/N) was pegged at 0.2 ng L−1 (5.31 × 10−13 mol L−1 RF). The proposed method was successfully applied to an actual human urine and drug sample, and can be applied to assays of other biological samples.  相似文献   

20.
Studies were conducted in the early season of 2002 and 2003 at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Nigeria to evaluate the effect of phosphorus (P) on fruit yield and chemical composition of two landraces of Trichosanthes cucumerina L. For the purpose of the study, two landraces of T. cucumerina named Landrace I and Landrace II were used. The five levels of phosphorus evaluated were 0, 30, 60, 90 and 120 kg P2O5 ha−1 using single super phosphate fertilizer (8% P). Statistical analysis showed that 90 kg P2O5 ha−1 gave statistically significant higher fruit yield (16.4 tons ha−1) compared to other P levels. The fruit yield of the two Landraces did not differ significantly. Except for crude protein content, the 90 kg P2O5 ha−1 produced significantly higher ether extract (1.22 g 100 g−1), crude fibre (1.93 g 100 g−1), moisture content (90.5 g 100 g−1), ash (0.90 g 100 g−1), total sugars (0.81 g 100 g−1) and ascorbic acid (28.7 mg 100 g−1) than other P levels. The essential amino acids compositions were also significantly higher at 90 g 100 g−1 compared to other lower P levels. Landrace I had significantly higher ether extract (0.90 g 100 g−1) content than Landrace II (0.62 g 100 g−1) while Landrace II in turn had significantly higher total sugar (0.76 g 100 g−1) compared to Landrace I (0.61 g 100 g−1). The essential amino acids composition is high and the oxalate composition is low. The high ascorbic acid and amino acid content together with a low oxalate composition suggested a strong basis for encouraging the cultivation of this indigenous fruit vegetable to augment nutrient requirement, improve diet and consequently alleviate poverty, preserve the biodiversity and increase the gene bank of neglected wild species of high quality nutrient sources.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号