Validation of an ICP-OES method for macro and trace element determination in Laminaria and Porphyra seaweeds from four different countries

An Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) method for speedy simultaneous determination of 12 elements (Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn) in seaweeds used as human food was optimized and then validated according to Eurachem guidelines. First, instrumental parameters (nebulizer argon flow rate and incident power) were optimized and then analytical lines free from spectral interferences were selected. The method was validated using biological Certified Reference Materials (CRMs). Intra- and inter-assay precision varied from 0.79% to 5.74% and from 2.48% to 8.57%, respectively, depending on the element studied. Within the experimental error, concentrations measured for each element coincided with certified values. Sensitivities, linearity and detection and quantification limits were also determined. Samples of seaweeds (Porphyra and Laminaria) from France, Spain, Korea and Japan were analyzed by using the optimized and validated method. Some considerations on element composition of analyzed samples were made. Seaweeds from the Korean and Japanese coasts tended to display the highest concentrations of P and Al. In contrast, French Porphyra samples showed the lowest levels of Ba, Cu, Fe and Mn. Because great differences in element concentrations were observed due to costal origin and genus, any generalization regarding the algal mineral content may be considered misleading and scientifically inappropriate.     

Selenium content of Portuguese unifloral honeys

The selenium contents of a total of 62 unifloral honeys from Erica spp., Castanea sativa, Eucalyptus spp., Lavandula stoechas, Citrus spp. and Echium plantagineum honeys collected in Portugal were determined by fluorometry after reaction with 2,3-diaminonaphthalene. The selenium levels of the honey samples studied were low, ranging from <1.0 to 2.91 μg/100 g fresh weight. The honeys from Erica spp., C. sativa and E. plantagineum presented the highest selenium values from all the honeys studied (median values 1.69, 1.51 and 1.51 μg/100 g fresh weight), and the honeys from Eucalyptus spp., L. stoechas and Citrus spp. presented the lowest values (median values 1.33, 1.28 and 1.20 μg/100 g fresh weight). The selenium content of Erica spp., was significantly higher than that observed for the Eucalyptus spp., L. stoechas and Citrus spp. and the selenium level of the Eucalyptus spp., was also significantly lower than that observed C. sativa and E. plantagineum honeys. From these results it can be concluded that honey is a marginal source of Se for the Portuguese population.     

Evaluation of microwave-assisted ultraviolet digestion method for rice and wheat for subsequent spectrometric determination of As,Cd, Hg and Pb

The aim of this study was to optimize a sample preparation method for rice and wheat using microwave-assisted ultraviolet digestion (MW-UV) for subsequent determination of toxic elements. Cadmium and Pb were determined by sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS), while As and Hg were determined by chemical vapor generation coupled to atomic absorption spectrometry (CVG-AAS). A systematic evaluation of the microwave heating program, nitric acid concentrationand sample mass was performed to optimize the MW-UV digestion method for rice and wheat samples. The relationship between nitric acid concentration and sample mass was monitored by determination of the residual carbon content (RCC) and residual acidity (RA) in order to obtain a high efficiency of digestion. The MW-UV method was successful at digesting up to 1100 mg of rice and wheat using 4 mol L⁻¹ HNO₃ with RCC and RA lower than 1.5 %, and 10 %, respectively. Recovery results ranging from 88 % to 117 % and agreement with certified reference values (t-test, 95 % confidence level) were obtained after digestion using the MW-UV method for spiked samples and certified reference materials (peach leaves-NIST 1547 and tomato leaves-NIST 1573), respectively. The optimized method was suitable for analysis of toxic elements in rice and wheat in compliance with the maximum levels reported in official directives.     

应用ICP-MS与AAS测定食品中铅、镉、铜方法研究及比较

目的:建立微波消解、电感耦合等离子体质谱法(ICP-MS)同时测定食品中微量元素的方法,并与国标法原子吸收分光光度法(AAS)进行了比较。方法:应用微波消解进行样品前处理,使用电感耦合等离子体质谱与原子吸收分光光度计分别测定三十余种食品中铅、镉、铜含量。结果:线性相关系数均大于三个9,方法的精密度均小于8.0%,国家标准物质:小麦粉(GBW08503b)、杨树叶(GBW08513)、贻贝(GBW08571)测定值均在标准值范围内,两种方法的测定值基本吻合。结论:ICP-MS法3种元素可同时分析,抗干扰强,但仪器成本高;AAS法每一元素需分别测定,测定周期较长,干扰较大,特别是高盐样品需稀释后测定,但仪器成本低,普及率高。     

Subcellular distribution of Cd and Pb in earthworm Eisenia fetida as affected by Ca2+ ions and Cd-Pb interaction

A semi-static solution culture method was used to study the effects of Ca²⁺ supply and interaction of Cd–Pb on the subcellular distribution of Cd and Pb in earthworm Eisenia fetida. The subcellular distribution of Cd and Pb was shown to be metal specific. About 80% of the Cd was distributed in the cytosol (fraction G), and only about 20% of total Cd was found in the tissue and cell membrane (fraction E) and the microsomes (fraction F). Nearly 50% of the Pb was rich in the tissue and cell membrane (fraction E). The supply of Ca²⁺ ions significantly decreased Cd concentration in the cytosol (fraction G) and the whole tissue of the E. fetida. At the subcellular level, the addition of Pb²⁺ ions significantly decreased the Cd percentage associated with fraction G from 83.7% to 58.4% and increased fraction E from 10.7% to 34.0%, respectively.     

Tolerance of the lichen Xanthoria parietina (L.) Th. Fr. to metal stress

Comparisons were made between the content of Al, Cd, Cu, Fe, Mn, Pb, Sb and Zn in thalli of the lichen Xanthoria parietina and selected physiological processes. Assimilation pigments, activity of photosystem II, parietin, reactive substances produced using thiobarbituric acid (TBA) and CO₂ gas exchange were measured in order to assess tolerance to atmospheric sources of pollution. As expected, lichen thalli accumulated high amounts of the measured elements in relation to distance from pollution sources in Košice, Slovak Republic (US Steel factory and vehicular traffic in the city center). However, except for TBA reactive substances production and to some extent CO₂ gas exchange at the most polluted station, none of the tested physiological parameters showed a clear correlation between accumulation of elements and physiological damage. This reflected a high degree of pollution tolerance in this lichen and corresponded with its high abundance in Košice.     

Comparative Tissue Distribution of Metals in Birds in Sweden Using ICP-MS and Laser Ablation ICP-MS

Cadmium, copper, lead, palladium, platinum, rhodium, and zinc profiles were investigated along feather shafts of raptor and other bird species by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The distribution of external versus internal metal contamination of feathers was investigated. The species examined were peregrine falcon (Falco peregrinus), sparrowhawk (Accipiter nisus), willow grouse (Lagopus lagopus), and house sparrow (Passer domesticus) in Sweden. For habitat comparisons, total Cu, Pb, Zn, and Cd concentrations were analyzed by ICP-MS in feathers of the examined species as well as captive peregrine falcon. For investigation of metal distribution and correlation in different biological materials of raptors, total concentrations of Cu, Pb, Cd, and Zn were also investigated by ICP-MS in feathers, eggs, blood, feces, liver, and kidney of wild peregrine falcon from southwestern Sweden.Laser ablation of feathers revealed that Pb contamination is both external and internal, Zn contamination is internal, and Cd and Cu contamination is predominantly internal, with a few externally attached particles of high concentration. Pb, Cu, and Cd signal intensities were highest in urban habitats and contamination was mainly external in feathers. The background signal intensity of Zn was also higher in birds from urban habitats. The laser ablation profile of PGE (Pt, Pd, Rh) demonstrated that PGE contamination of feathers consists almost exclusively of externally attached PGE-containing particles, with little evidence of internally deposited PGE.Generally, total metal concentrations in feathers were highest in sparrowhawk and house sparrow due to their urban habitat. Total Cu, Zn, and Cd concentrations were highest in liver and kidney due to binding to metallothionein, while the total Pb concentration was highest in feces due to the high excretion rate of Pb. A decreasing temporal trend for Pb in feathers, showing that Pb levels in feathers have decreased since the introduction of nonleaded petrol, is also discussed.     

The Metal Content of Bivalve Molluscs of a Coastal Lagoon of NW Mexico

The lagoonal system Altata-Ensenada del Pabellón supports important traditional fisheries and mollusc cultures and receives urban and agricultural effluents. The annual mean Cd contents of the oyster and mussel Crassostrea gigas and Mytella strigata of the inner mangrove swamps were higher than that of the clam Megapitaria squalida, which lives in areas under marine influence. Crassostrea corteziensis had the highest Cu and Zn contents, showing that it is a strong accumulator of both metals and especially of Zn, and there were no significant differences in the Pb content of the three species.     

ICP-MS法测定镍矿生产粉尘中金属含量

目的建立利用电感耦合等离子体质谱法(ICP-MS)分析镍矿各生产环节粉尘中多元素分析的方法并分析镍及其他六种金属的含量。方法采集镍矿各生产环节中粉尘,优化ICP-MS的最佳测定条件,在一次检测中同时测定粉尘中的Ni、Mn、Cu、Cd、Pb、Sb 6中金属元素。结果方法的精密度与准确度良好,回收率为90.0%～106.3%。结论该方法准确、快速、简便,可同时用于镍矿生产职业接触粉尘中多种金属元素的测定,结果满意。     

Rapid assessment of metal contamination in commercial fruit juices by inductively coupled mass spectrometry after a simple dilution

A simple and fast method for the determination of Ca, Cd, Co, Cu, Fe, Mn, Mo, Na, Ni, Pb, Rb, Sr, V and Zn in fruit juices samples, by inductively coupled plasma mass spectrometry (ICP-MS) after only a sample dilution, is proposed. For comparison, the samples were also digested with nitric acid and hydrogen peroxide in a microwave oven. The same conditions could be used for aqueous standard solution and diluted sample and the sensitivity was similar in both media, thus external calibration against aqueous standard solutions could be used for quantification. The results were in agreement with those obtained after digestion, according to the t-test at a 95% confidence level. The good accuracy was also confirmed by the recovery test. The precision expressed by the relative standard deviation (RSD) was between 1 and 3%. The detection limits were between 0.1 (Pb) and 2000 μg L⁻¹ (Ca). Similar values for detection limits and RSD were obtained after sample digestion or when the internal standard was not used. The compositions of 20 samples were evaluated by multivariate analysis techniques: principal component analysis (PCA) and hierarchical cluster analysis (HCA), showing that samples are grouped by the brand and not by the fruit, what could be due to soil characteristics where the plant was grown and to the different processing and storage conditions used by the different brands, including water and additives.     

Cadmium bioaccumulation in Proisotoma minuta in relation to bioavailability in soils

Proisotoma minuta are widely distributed in Australian soils, especially in rehabilitated mine sites and in cotton fields. Laboratory studies were conducted to evaluate the accumulation of cadmium (Cd) in the Collembolan, P. minuta, using four Australian soils. Cadmium accumulation in body tissues was measured by atomic absorption spectroscopy of acid digests of the Collembola. Cadmium soil bioavailability of four Australian soils was determined using a sequential extraction method. The highest soluble-exchangeable Cd concentration was observed in Box Hill soil with the lowest pH, organic carbon, CEC, clay and very low iron content. Robertson soil with high pH, CEC, organic carbon, clay and iron content had the highest Cd organic- and oxide-bound concentrations. This may explain why there was higher Cd accumulation in P. minuta in the Box Hill soil than in the Robertson soil. The Cd uptake of P. minuta was predominantly correlated with soluble-exchangeable Cd concentration in soils followed by organic- and oxide-bound Cd concentrations. Presumably, soluble-exchangeable Cd is more readily available for P. minuta uptake than other Cd fractions.     

Contamination levels of lead, cadmium and mercury in imported and domestic lobsters and large crab species consumed in France: Differences between white and brown meat

Lead, cadmium and total mercury contents have been determined by atomic absorption spectrometry in white and brown meat of 108 batches of crustaceans (lobsters, spider crabs, common crabs, swimming crabs and king crabs) collected in France between April and December 2009. With mean levels of 0.041, 0.132 and 0.128 mg kg⁻¹ for Pb, Cd and Hg, respectively, concentrations in white meat were systematically below the European legislation maximum level of 0.50 mg kg⁻¹. Cd concentration in the brown meat of common crabs (mean concentration: 11.8 mg kg⁻¹ and maximum of 14.3 mg kg⁻¹) was well above the observed levels for white meat. The consumption of one whole common crab of 1 kg (about 120 g of white and brown meat) would not contribute significantly to the Pb and Hg provisional tolerable weekly intake (PTWI) for adults, but the ingested Cd would greatly exceed the TWI of 2.5 μg kg⁻¹ body weight, which may be a health issue for consumers of brown meat. Therefore, we recommend moderate brown meat consumption.     

Using estimates of metal bioavailability in the soil and genetic variation of allozymes to investigate heavy metal tolerance in the earthworm Eisenia fetida (Oligochaeta)

In a recent study, we showed that the earthworm species Eisenia fetida, inhabiting an extremely high metal polluted compost heap on a wine farm, did not have elevated body loads of the metals but exhibited genotoxic tolerance when exposed to Cd in the laboratory (Voua Otomo and Reinecke, 2010). To unravel the mechanism behind the surprisingly low metal body burdens on one hand and genotoxic tolerance on the other hand, we investigated the estimated bioavailability of these metals (Cu, Zn, Pb and Cd) using sequential extraction methods with CaCl₂ and di-ethylene-triamine-pentaacetic acid (DTPA) and allozyme polymorphism in this field population, a laboratory control as well as a long-term Cd exposed population. The amounts of mobile (extracted with CaCl₂) and mobilizable (extracted with DTPA) metals in relation to the total (extracted with nitric acid) metals were all below 0.05% for all four metals, suggesting low availability for uptake. The low availability of these metals could not be explained by physico-chemical properties of soil but by the phenomenon of aging of the metals. There was no difference in allozyme frequency between metal tolerant and non-metal tolerant populations of E. fetida. This suggested that the tolerance found in earlier studies could be a mere physiological adaptation     

Evaluation of different digestion systems for determination of trace mercury in seaweeds by cold vapour atomic fluorescence spectrometry

Four methods for acid digestion of seaweeds were compared in 10 commercially available seaweeds: (i) in stainless steel-Teflon^®PTFE-bombs at high pressure and temperature, (ii) in closed-Teflon^®PFA-vessels at high pressure and temperature, (iii) in open-polypropylene-tubes with reflux caps in a graphite heating block at high temperature and (iv) in closed-TFM™PTFE-vessels with microwave-assisted controlled pressure and temperature. Hg was determined in all digests by cold vapour atomic fluorescence spectrometry (CV-AFS). Assessment of digestion methods was performed by comparison with the results obtained for total mercury determination by the Method EPA 7473, based on direct mercury analysis in the solid samples, and with a reference material BCR-279. The open vessel digestion system with reflux in a graphite heating block at high temperature constitutes the best choice since it was found to give the better Hg extraction (83–103%) as well as the lowest variability, being RSD < 10% for most of the studied seaweeds. A previous freeze-drying and intensive grinding was the best pre-treatment. Similar results were obtained with and without the presence of oxidizing agents (KMnO₄, K₂Cr₂O₇) and with different tube-materials (borosilicate glass, PTFE and polypropylene).     

Cross-Border Response of Moss, <Emphasis Type="Italic">Hypnum cupressiforme</Emphasis> Hedw., to Atmospheric Deposition in Southern Bulgaria and Northeastern Greece

This study aimed at first cross-border mapping of 10 heavy metals and toxic elements accumulation in moss Hypnum cupressiforme reflecting wet and dry atmospheric deposition in Southern Bulgaria and Northeastern Greece. It is a part of the European moss survey 2005/2006 including first Greek results. Data obtained from 66 sites, covering 20,000 km², showed different deposition patterns particularly for As, Cd, Cr and Pb. The determined concentrations (ICP–AES), revealed no serious pollution by airborne heavy metals and toxic elements contaminants. Lead was the only element with proved statistical significant difference, between Bulgarian and Greek part of the study area.     

Comparison of Organochlorine Pesticides,PCBs, and Heavy Metal Contamination and of Detoxifying Response in Tissues of <Emphasis Type="Italic">Ameiurus melas</Emphasis> from Corbara,Alviano, and Trasimeno Lakes,Italy

Accumulation of cadmium (Cd), mercury (Hg), lead (Pb), chromium (Cr), hexachlorobenzene, γ-HCH, DDTs, and PCBs has been investigated in the muscle of Ameiurus melas sampled during the same period from Lake Corbara, Alviano, and Trasimeno. Glutathione content and the enzymatic activities of glutathione reductase, glutathione peroxidase, catalase, glutathione S-transferase, and glyoxalase I were examined in gills, liver, and kidneys of each specimen. Catfish from Alviano, compared to those of Corbara and Trasimeno, showed the highest contamination of DDTs and PCBs and the lowest levels of biochemical parameters. Most likely, OCPs and PCBs content might be responsible for the compromised antioxidant status in these specimens.     

微波消解-电感耦合等离子体质谱法测定小麦中的8种元素

目的利用微波消解-电感耦合等离子体质谱法测定小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的含量。方法样品经过微波消解后,用ICP-MS法同时测定小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的含量,以45 Sc、72Ge、103Rh、209Bi作为内标元素采用电感耦合等离子体质谱法测定,用标准曲线法进行定量。结果小麦中Pb、Cd、As、Cr、Se、Ni、Al、Cu的回收率在95.6%~106.8%,线性相关系数(r)≥0.9995,Pb、Cd、As、Cr、Se、Ni、Al、Cu的检出限分别为0.0049μg/L、0.0023μg/L、0.012μg/L、0.016μg/L、0.026μg/L、0.0099μg/L、0.0070μg/L、0.0027μg/L;生物成分分析标准物质(小麦)的各元素的测定结果均在标准值不确定度范围内;同时对3份小麦样品进行连续6次测定,各元素的相对标准偏差(RSD)≤5%。结论本法线性范围宽、抗干扰能力强、测定周期短,完全满足分析的要求,适用于日常样品的检测。     

Rapid determination of toxic and rare-earth elements in teas by particle nebulization-ICPMS

Toxic elements profiling of teas is vital in terms of both quality control as well as a means to generate a comprehensive database for human-health-risk assessment. Accordingly, in the present study, a rapid method using direct nebulization of tea particles for inductively coupled plasma (ICP) ionization and subsequent detection of toxic elements by mass spectrometry (MS) was developed. Dried and well grounded tea particles were stably dispersed in 0.5% polyethylene-imine and the particle slurries were analyzed by ICP-MS using aqueous standard calibration. Monitoring the nebulization, transportation, and ionization behaviors of particles of different sizes revealed that particles with a mean size of 1 μm provide values comparable with those of aqueous standards containing equivalent concentrations of the analyte. The excellent recoveries of the method (90–105%) were verified by analyzing two tea certified reference materials, and the detection limits ranged from 0.03 (for Tm) to 1.2 (for Cr) μg kg⁻¹. Then, we performed screening analysis of five toxic elements (As, Cd, Cr, Hg, and Pb) and 16 rare-earth elements in 20 Pu’er teas, and the results revealed that the contents of all the toxic elements and heavy rare earth oxides were low level, where those of the light rare-earth oxides were high. Furthermore, the total rare-earth oxides content of 30% of the Pu’er teas exceeded the Chinese National limit.     

湖南省细菌耐药监测网2012—2021年葡萄球菌属细菌耐药性监测报告

目的 了解2012—2021年湖南省临床标本分离病原菌中葡萄球菌属的分布及耐药性,为临床抗菌药物合理应用,以及制定和评价抗菌药物临床应用管理政策提供科学依据。方法 按照全国细菌耐药监测网(CRASS)技术方案,应用WHONET 5.6软件对2012—2021年湖南省细菌耐药监测网上报的葡萄球菌属耐药性进行分析。结果 2012—2021年,葡萄球菌属中分离稳居前4位的细菌分别为金黄色葡萄球菌、表皮葡萄球菌、溶血葡萄球菌和人葡萄球菌。葡萄球菌属标本来源以痰、血、分泌物、伤口脓液和尿为主,其中痰标本占25.4%～31.8%,血标本占21.9%～27.8%。在所有临床分离的细菌中,葡萄球菌属占比为15.5%～22.4%,呈现缓慢下降的趋势。10年来,耐甲氧西林金黄色葡萄球菌(MRSA)检出率有所下降,从35.1%下降至24.8%,同时耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)检出率有所上升,但是仍保持在70%以内。葡萄球菌属细菌对万古霉素、替考拉宁和利奈唑胺的敏感率为100%。结论 湖南省临床分离葡萄球菌属细菌中,MRSA检出率有所下降,未发现对万古霉素、替考拉宁和利奈唑胺耐药的葡萄球菌属细菌...     

湛江硇洲岛沿海12种常见食用海藻微量元素分析

采用电感耦合等离子体质谱仪(ICP-MS),对中国湛江硇洲岛沿海12种常见食用海藻的微量元素进行含量测定与分析。实验结果发现12种食用海藻的微量元素含量丰富,其中以Ca、Mg、Fe、Mn、P、Zn含量较高,而重金属元素As含量较高,均严重超标,Al、Cd含量较低,均未见超标。褐藻门藻类Ca含量比较高,绿藻门藻类Mg、Fe、Mn、Zn、Cu含量比较高,红藻门藻类P含量比较高。12种不同海藻中各种微量元素含量存在显著差异,对这些微量元素进行了分析和比较,旨在为食用海藻的食用和药用提供参考。