Metallic content of wines from the Canary Islands (Spain). Application of artificial neural networks to the data analysis

Eleven elements, K, Na, Ca, Mg, Fe, Cu, Zn, Mn, Sr, Li and Rb, were determined in dry and sweet wines bearing the denominations of origin of El Hierro, La Palma and Lanzarote islands (Canary Islands, Spain). Analyses were performed by flame atomic absorption spectrophotometry, with the exceptions of Li and Rb for which flame atomic emission spectrophotometry was used. The content in copper and iron did not present risks of cases. All samples presented a copper and zinc content below the maximum amount recommended by the Office International de la Vigne et du Vin (OIV) for these elements. Significant differences in the metallic content were found among the different islands. Thus, Lanzarote presented the highest mean content in sodium and lithium and the lowest mean content in rubidium, and La Palma presented the highest mean content in strontium and rubidium. Sweet wines from La Palma, elaborated as naturally sweet with over-ripe grapes, presented mean contents significantly higher with regard to dry wines from the same island in the majority of the analysed elements. Cluster analysis and Kohonen self-organising maps showed differences in wines according to the island of origin and the ripening state of the grapes. Back-propagation artificial neural networks showed better prediction ability than stepwise linear discriminant analysis.     

Quantity of K, Ca, Na, Mg, Fe, Cu, Pb, Zn and ashes in DOC Tacoronte-Acentejo (Canary Islands, Spain) musts and wines

This study determines ash, K, Ca, Na, Mg, Fe, Cu, Pb, and Zn content in musts and wines of the DOC Tacoronte-Acentejo (Tenerife, Canary Islands) from two consecutive harvests. Samples were treated with HNO₃ and H₂O₂. Na and K were determined by flame photometry and the remaining metals by air/acetilene flame atomic absorption spectrophotometry. Significant differences were observed in Na, Ca and Mg contents between both harvests, possibly due to climate conditions.     

Mineral profile of “fino” wines using inductively coupled plasma optical emission spectrometry methods

Fifty wines from the Denomination of origin (DO) of Condado de Huelva were analysed for mineral content by measuring 12 elements (Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn) using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Samples were previously digested by heating with H₂O₂/HNO₃ mixture. The results obtained showed that metal data set were non-normally distributed and accordingly, non-parametric statistics were applied. The average levels (medians) of these elements found in the samples are as follows, in mg/L: 2.54 (Al); 0.06 (Ba); 82.58 (Ca); 0.21 (Cu); 3.53 (Fe); 865.34 (K); 68.87 (Mg); 0.71 (Mn); 32.77 (Na); 71.61 (P); 0.48 (Sr); 0.56 (Zn). The interrelation of metal couples was studied through the Spearman non-parametric sample correlation, being Fe/Al, P/Mg, and Zn/Ba the most important correlations established. As a result of this study, we can suggest that the contribution to the safety intake limits (per week) of the studied elements through the wine consumption is not significant. Actually, they range between 0.1% in Fe and 11.9% in Mg, for normal drinkers.     

Multi-element analysis of tea beverages by inductively coupled plasma atomic emission spectrometry

The metal content of several tea beverages, infusions, instant and tea soft drinks was determined. Eleven metals Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn were determined by inductively coupled plasma atomic emission spectrometry (ICP–AES). A study of the differences in the metal contents of tea beverages has been carried out. Pattern recognition techniques such as principal components analysis and linear discriminant analysis were used to discriminate between the tea beverages. The metal intake related to tea consumption has also been studied.     

Trace elements in Pleurotus sajor-caju cultivated on chemithermomechanical pulp for bio-bleaching

Some trace elements were analyzed in Pleurotus Sajor-caju mushroom cultivated on chemithermomechanical pulp. In this experiment, phytohormones, such as 2.4-D and PS A6, were studied at concentrations of 10, 20 and 30 mg/100 ml, mixed into the pulp. Determination of mineral elements was done by flame atomic absorption spectrophotometry (Perkin Elmer model 1100 B). Sixteen mineral elements were determined in all samples. Cu, Mg, Pb, Na, Ag, Bi, Mn, Ni, Li, Co, Sb, Ca, Zn, Fe, Cr and Al contents of mushrooms, grown on treated pulp, were near control values. K was not present.     

大连湾牡蛎中微量元素的分析

采用火焰原子吸收光谱法(FAAS)对牡蛎及其内脏中钠、铜、锌、铁、铅、锶、锰、钙8种微量元素的含量进行连续测定,并时其测定结果作对比分析.同时考察不同消解方法对分析结果的影响,并用加标回收法对比检验方法的可靠性.结果表明:微渡消解法效果较好,相对标准偏差在3.04%以下,回收率为96.89%～104.33%之间.牡蛎中含有丰富的微量元素Na、Cu、Zn、Fe、Sr、Mn、Ca,特别是Cu、Zn含量较高.牡蛎内脏中Na、Cu、Zn、Fe、Mn含量高于完整牡蛎中含量,Sr、Ca含量低于完整牡蛎中含量.牡蛎及其内脏中均未检出Pb.     

Flavoured versus natural waters: Macromineral (Ca,Mg, K,Na) and micromineral (Fe,Cu, Zn) contents

Macro (Ca, Mg, K, Na) and micromineral (Fe, Zn, Cu) composition of 39 waters was analysed. Determinations were made by atomic flame spectrophotometry for macrominerals and electrothermic atomisation in graphite furnace for microminerals.     

Elemental fingerprint of wines from the protected designation of origin Valencia

Inductively coupled plasma optical emission (ICP-OES), in combination with different chemometric approaches, has been used to verify the origin of different red wine samples from Utiel-Requena, Jumilla, Yecla and Valencia protected designation of origin (PDO). The ability of multivariate analysis methods, such as hierarchical cluster analysis (HCA), principal component analysis (PCA), classification and regression trees (CARTs) and discriminant analysis (DA), to achieve wine classification from their elemental contents has been investigated. The calculations were performed using 38 variables (contents of Al, Ba, Be, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, Pb, Pr, Sc, Se, Sm, Sr, Tb, Ti, Tm, V, Y, Yb and Zn, at mg l⁻¹ level, determined by ICP-OES).     

Simplified multi-element analysis of ground and instant coffees by ICP-OES and FAAS

A simplified alternative to the wet digestion sample preparation procedure for roasted ground and instant coffees has been developed and validated for the determination of different elements by inductively coupled plasma optical emission spectrometry (ICP-OES) (Al, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Sr, Zn) and flame atomic absorption spectrometry (FAAS) (Ca, Fe, K, Mg, Na). The proposed procedure, i.e. the ultrasound-assisted solubilisation in aqua regia, is quite fast and simple, requires minimal use of reagents, and demonstrated good analytical performance, i.e. accuracy from ?4.7% to 1.9%, precision within 0.5–8.6% and recovery in the range 93.5–103%. Detection limits of elements were from 0.086 ng ml^?1 (Sr) to 40 ng ml^?1 (Fe). A preliminary classification of 18 samples of ground and instant coffees was successfully made based on concentrations of selected elements and using principal component analysis and hierarchic cluster analysis.     

Contribution to the study of avocado honeys by their mineral contents using inductively coupled plasma optical emission spectrometry

Avocado honey samples were analyzed by inductively coupled plasma optical emission spectrometric. First, the botanical origin of the honeys was confirmed by melissopalynological analysis. Twenty-four minerals were quantified for each honey sample. The elements Al, Ba, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Se, Si and Zn were detected in all samples; seven elements were very abundant (Ca, K, Mg, Na, P, S and Si), six were not abundant (Al, Cu, Fe, Li and Zn) and 11 were trace elements (As, Ba, Cd, Co, Cr, Mo, Ni, Mo, Pb, Se, Sr and V).     

Minor and trace elements in different honey types produced in Siena County (Italy)

The concentrations of 23 chemical elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Sb, Se, Sr, Th, Tl, U, Zn) were determined in 51 honey samples of different botanical origin produced in Siena County (Italy). K, Ca, Na and Mg were the most abundant elements, with mean contents of 1195, 257, 96.6 and 56.7 mg/kg, respectively. The Fe, Zn and Sr contents generally ranged from 1 to 5 mg/kg. Except for Ba, Cu, Mn and Ni, the trace element contents were below 100 μg/kg. The analytical data indicated a good level of quality of the honeys, especially with regard to the concentrations of toxic trace elements, such as As, Cd, Pb and Sb, and suggested a significant influence of the botanical origin on the element composition. Some local geological and geochemical features also seemed to affect the chemistry of the honey.     

Determination of industrial pollution effects on citrus honeys with chemometric approach

The aim of this study was to determine the levels of essential, trace and toxic elements, such as K, Ca, Fe, Cu, Al, Ni, Sn, Pb and Cd in citrus honeys from different regions (industrialized and nonindustrialized) of Hatay, Turkey. K, Ca, Na and Mg were the most abundant elements, with mean contents of 363.5, 256.6, 88.1 and 37.7 mg/kg, respectively. The trace element mean contents ranged between 0.032 and 15.58 mg/kg. Significant differences in Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr levels were observed between two different regions. The findings that Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr contents in citrus honeys from industrialized regions were higher than citrus honeys from non-industrialized regions indicate that the honeys were affected by industrial pollution. Chemometric methods were applied to classify honey according to mineral content. Cluster analysis showed three clusters corresponding to the three different regions.     

Mineral composition of isolated fibre fractions from artichoke and the effect of phosphate buffer on its structure and mineral content

Soluble and insoluble dietary fibre of artichoke heart were extracted in water and phosphate buffer to determine their mineral contents and to evaluate the effect of the extraction medium on fibre structure (studied by scanning electron microscopy) and mineral composition (determined by X-ray microanalysis and atomic absorption spectrophotometry). The undialysed soluble dietary fibre extracted with phosphate buffer showed a different structural organisation from that extracted with water. X-Ray microanalysis of both soluble fractions showed some differences between the Na, K, Ca and P contents, and also between the Na contents of the insoluble fractions. However, when the samples were dialysed, differences in morphology and structure between the soluble fractions were not observed. A study of the mineral composition by atomic absorption showed differences between both soluble fractions and both insoluble fractions as regards Na, Ca, Mg and Fe.     

Differentiation of Romanian Wines on Geographical Origin and Wine Variety by Elemental Composition and Phenolic Components

Several wines were analyzed by high-performance liquid chromatography (HPLC-PDA), inductively coupled plasma mass spectrometry (ICP-MS), and flame atomic absorption spectroscopy (FAAS) in order to associate the concentration levels of the chemical parameters with the geographical origin of wines and wine varieties. Thus, the concentrations of 22 elements (Li, Be, Co, Ni, Cs, U, Pb, V, As, Ba, Cr, Cu, Zn, Al, Mn, Rb, Sr, Fe, Ca, Mg, Na, and K) and seven phenolic compounds (gallic acid, (+)-catechin, (?)-epicatechin, p-coumaric acid, ferulic acid, trans-cinnamic acid, and resveratrol) were analyzed in 22 wines from two different wine-producing areas of Romania. Among the phenolic compounds, (+)-catechin, (?)-epicatechin, p-coumaric acid, ferulic acid, and resveratrol concentrations were the most useful markers for wine differentiation by geographical origin and wine variety, whereas Ba, Be, Cr, Cs, Li, Mg, Na, Ni, Sr, U, and Zn were the main inorganic parameters selected. To explore the distribution pattern of the samples, aimed at differentiating the wine samples by geographical region and wine variety, principal component analysis (PCA) was applied to the obtained data.     

慕萨莱思葡萄酒中13种常见金属元素及硒含量分析

采用火焰原子吸收光谱法、石墨炉原子吸收光谱法和原子荧光光度法测定阿瓦提慕萨莱思成品酒、红提葡萄原汁、实验室自酿慕萨莱思及酒泥中镁（Mg）、铁（Fe）、铜（Cu）、锰（Mn）、锌（Zn）、钙（Ca）、铅（Pb）、镉（Cd）、镍（Ni）、铬（Cr）、钴（Co）、钾（K）、钠（Na）和硒（Se）14种元素含量。结果表明,慕萨莱思葡萄酒中富含Na、K、Fe、Mg、Ca和Se,其Pb、Cd和Cr等重金属元素均符合国家标准限量,但阿瓦提慕萨莱思葡萄酒中Fe含量显著高于实验室自酿慕萨莱思（P＜0.01）,为12.13～13.35 mg/L,已超出我国葡萄酒国家标准（≤8 mg/L）,但未超出新疆地方标准的限量（≤15 mg/L）。此外,酒泥中富含绝大多数金属元素和Se。由此,实验室自酿慕萨莱思的酿制工艺可有效降低Fe含量。     

Cadmium,lead and some other trace elements in Larch Bolete mushrooms (Suillus grevillei) (Klotzsch) Sing., collected from the same site over two years

The aim of this study was to examine the status of some trace metals accumulated in the flesh of Suillus grevillei mushrooms collected from the same site over two successive years. Total Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr and Zn contents of fruiting bodies were determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) with ultrasonic cross-flow nebuliser. A difference (p < 0.05) was found in the contents of Cd, Cr, Cu, Fe, K, Na, Ni, Pb, Rb and Sr in caps and Fe, Na, P and Rb (p < 0.05) in stipes (Ag, Cd, Co, Cr, Ni and Pb were not determined in stipes). Natural fluctuations in trace elements’ content of Suillus grevillei collected from the same site over time is a variable that needs to be considered when assessing minerals’ nutritional status of mushrooms.     

Simultaneous Determination of 20 Inorganic Elements in Preserved Egg Prepared with Different Metal Ions by ICP-AES

In the present study, 20 inorganic elements in three parts of preserved eggs prepared with different metal ions, including Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Li, K, Mg, Mn, Mo, Na, P, Pb, Zn, Se, and Sr, were determined simultaneously by using inductively coupled plasma–atomic emission spectrometry (ICP-AES). The recoveries obtained by the standard addition method ranged between 84.4 and 112.2 %, and RSDs were lower than 8.76 %, The detection limits of the method for the 20 elements were in the range of 0.4–10 μg?L^?1. The determination results showed that three parts of preserved eggs prepared with different metal ions are all rich in essential inorganic elements, such as Na, K, P, Ca, Mg, Fe, Cu, and Zn, and the contents of most of the inorganic elements in egg yolk are higher than in egg white. In comparison with fresh duck eggs, the contents of Na, Cu, Fe, Al, and Mn are significantly increased in three parts of preserved eggs prepared with different metal ions. Metal ions added in pickling solution would significantly affect the content of element added in preserved eggs. High contents of Pb (20.15 μg/g in egg shell, 18.99 μg/g in egg white, and 0.96 μg/g in egg yolk) were found in preserved eggs with PbO. Meanwhile, the experimental results indicated that the ICP-AES technique is easy to operate, rapid, accurate, and highly sensitive to determine many inorganic elements simultaneously in preserved egg.     

金属元素在汾酒中的作用及应用研究

采用火焰原子吸收法测Na、K、Ca、Mg、Fe、Zn、Cu、Mn、Ni、Li、Pb、Cd 和Cr 含量;石墨炉原子吸收法测Mo、Sr、Ba、Co、Ti、Al 和Sn 含量;原子荧光光度法测Hg、As、Se 和Sb 含量,对汾酒不同生产用水、不同贮存容器所贮新酒中24 种金属元素进行了定量分析,并初步探讨了酒中金属元素的作用机制。结果显示,汾酒中金属元素的种类和含量与生产用水及贮存容器的使用密切相关,因此用不同的水源和容器,酒中金属元素的种类和含量不同,从而影响汾酒的口感和老熟。在此基础上,对汾酒生产中合理使用水源和容器也做出了科学合理的指导。     

基于电感耦合等离子体质谱法对不同产地小米矿物元素的差异性分析

采用电感耦合等离子体质谱法对小米（陕西、山西、内蒙古、河北、山东、东北产区）6大主产区不同品种样品的矿物元素进行检测,研究不同产地品种来源小米K、Ca、Na、Mg、Al、Fe、Cu、Zn、Mn、Se、B、Ti、Co、Sr、Mo 15种矿质元素含量差异并分析其显著性,同时采用主成分分析法和聚类分析法对不同产地小米矿质元素含量的差异进行分析,检测结果表明,不同产地品种小米元素含量差异显著,Se、Sr、Al 三种元素含量差异最为明显,变异系数最高,Zn、Cu、K 三种元素的变异系数最小。主成分分析结果表明,前两个主成分方差贡献率为 63.9%,K、Ca、Mg、Fe、Cu、Zn、Mn、B、Mo、Al、Se、Sr、Ti 是不同品种及产地来源小米的特征差异元素;聚类分析结果表明品种对小米元素分布造成的影响有限,地域环境因素是造成小米元素分布差异的主要因素。     

Geographical Authentication of Tequila According to its Mineral Content by Means of Support Vector Machines

The elemental profile of tequila samples from the three main production areas of the State of Jalisco, namely Amatitlan, Guadalajara, and Tequila, was used to carry out their geographical characterization. With this aim, the concentration of Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, S, Sr, and Zn was determined by inductively coupled plasma atomic emission spectroscopy. Principal component analysis was addressed to visualize data trends. The number of input variables was reduced by means of backward stepwise linear discriminant analysis and support vector machines were used to construct an adequate classification model. The best classification performance was obtained by a linear support vector machine model with 100% of prediction ability.