Fabrina Regia Stumm Bentlin

Elemental Analysis of Wines from South America and their Classification According to Country

Elementos majoritarios, minoritarios e traco em vinhos provenientes de paises produtores na America do Sul (Argentina, Brasil, Chile e Uruguai) foram determinados. A espectrometria de emissao optica com plasma indutivamente acoplado (ICP OES) e a espectrometria de massa com plasma indutivamente acoplado (ICP-MS) em conjunto com nebulizacao pneumatica e/ou nebulizacao ultra-sonica foram utilizadas. Foram determinados 45 elementos (Al, Ag, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pr, Rb, Sb, Sn, Se, Sm, Sr, Tb, Ti, Tl, Tm, U, V, Yb e Zn) em 53 vinhos tintos. Mediante analise multivariada, os vinhos puderam ser discriminados de acordo com o pais de origem, independentemente do tipo da uva. Os elementos discriminantes foram Tl, U, Li, Rb e Mg. Major, minor and trace elements in wines from wine-producing countries in South America (Argentina, Brazil, Chile, and Uruguay) were determined. Inductively coupled plasma optical emission spectrometry (ICP OES) and inductively coupled plasma mass spectrometry (ICP-MS) combined with pneumatic and/or ultrasonic nebulization were used. The concentrations of 45 elements (Al, Ag, As, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pr, Rb, Sb, Sn, Se, Sm, Sr, Tb, Ti, Tl, Tm, U, V, Yb, and Zn) in 53 red wines were determined. By means of multivariate analysis, the wines could be discriminated according to the country of origin, regardless of the type of grape. The discriminant elements were Tl, U, Li, Rb, and Mg.

Methodology for Hg determination in honey using cloud point extraction and cold vapour-inductively coupled plasma optical emission spectrometry

This paper describes the development of a method for the determination of mercury in honey. Analyte pre-concentration/matrix separation is carried out by cloud point extraction (CPE), while cold vapour-optical emission spectrometry (CV-ICP OES) is used to detect the analyte. A careful analytical work was carried out in order to evaluate precision and accuracy of the method. Mercury was complexed with ammonium diethyldithiophosphate (DDTP) and Triton X-114 was used as surfactant. Parameters such as type and concentration of acid (HCl or HNO3 + KCl), concentrations of complexant, surfactant and reductant (NaBH4), dilution of the surfactant-rich phase and the mass of honey were evaluated. Two procedures of sample preparation were investigated: sonication in presence of L-cysteine and acid decomposition in closed vessel. Sonication was very effective for extraction of inorganic mercury (Hg2+), but it was observed the sample should be decomposed to ensure the quantification of total mercury. Certified dog fish liver, analyte recovery and comparison with an independent technique (cold vapour-inductively coupled plasma mass spectrometry) were used to evaluate the method. Analyte recovery close to 100% was observed when up to 2.0 g of honey were subjected to sonication or up to 1.0 g of honey was decomposed with acid. The enrichment factor (EF) obtained was 13 and the limit of detection (LOD) was 2.2 ng g−1. The Hg concentration in the analyzed samples was lower than the LOD.

Lanthanides determination in red wine using ultrasound assisted extraction, flow injection, aerosol desolvation and ICP-MS.

This paper deals with the determination of the fourteen naturally occurring elements of the lanthanide series in red wine. Ultrasound (US) was used for sample preparation prior lanthanides determination using ICP-MS. Flow injection (FI) and pneumatic nebulization/aerosol desolvation were used for nebulization of aliquots of 50 μL of sample and its subsequent transportation to plasma. Sample preparation procedures, matrix interference and time of sonication were evaluated. Better results for lanthanides in red wine were obtained by sonication with US probe for 90 s and sample 10-fold diluted. The limits of detection of La, Ce, Nd, Sm, Gd, Pr, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb were 6.57, 10.8, 9.97, 9.38, 2.71, 1.29, 1.22, 0.52, 2.35, 0.96, 2.30, 0.45, 0.24 and 1.35 ng L(-1), respectively. Red wines of different varieties from three countries of South America were discriminated according to the country of origin by means of multivariate analysis of lanthanides concentration.

Multivariate optimization for cloud point extraction and determination of lanthanides

A cloud point extraction (CPE) method is proposed for pre-concentration of lanthanides and subsequent determination using inductively coupled plasma optical emission spectrometry (ICP OES). Octylphenoxypolyethoxyethanol (Triton X-114) and 1-(2-thenoyl)-3,3,3-trifluoraceton (TTA) are used as surfactant and complexant of the lanthanides, respectively. A three-factor Doehlert matrix design with seven, five, and three levels is used to optimize the TTA and Triton X-114 concentration and the pH of the solution, respectively. The better conditions for pre-concentration are 0.001 to 0.005 mol L−1 TTA, 0.05 to 0.3% (m/v) Triton X-114 and pH from 5.5 to 7.0. Under these conditions, the fourteen naturally occurring lanthanide elements can be pre-concentrated together and then measured. The conditions established were pH 6.0 and 0.175 (m/v) Triton X-114 for all investigated elements; 0.005 mol L−1 TTA for Sm, Eu, Gd, Tb, Ho, Yb and Lu; and 0.001 mol L−1 TTA for La, Ce, Pr, Nd, Dy, Er and Tm. By using axially viewed plasma and pneumatic nebulization/aerosol desolvation, the limits of detection were 0.028, 0.099, 0.103, 0.020, 0.018, 0.014, 0.013, 0.047, 0.015, 0.009, 0.022, 0.003, 0.002 and 0.002 μg L−1 for La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, respectively. The proposed method was applied for lanthanides determination in mineral water, river water and reference water.

Estudo comparativo de métodos de preparo de amostras de tinta para a determinação de metais e metalóides por técnicas de espectrometria atômica

This work deals with paint decomposition methods for major, minor and trace elements determination. Three methods were investigated: (1) decomposition in closed quartz vessel and heating in microwave oven; (2) decomposition in open vessel using HNO3 and ashing, following the ASTM D 3335-85a method; and (3) decomposition in open vessel using HNO3 + HF and ashing. Paints of different types and colours were analyzed, in which several elements were determined using inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP OES). It was observed that method (1) is appropriate for trace, minor and major elements determination, while method (3) is appropriate for Ti.