Evaluation of sample preparation procedures and krypton as an interference standard probe for arsenic speciation by HPLC-ICP-QMS

Different conditions of extraction using water, a methanol-water mixture and nitric acid solutions were evaluated for speciation of As(iii), As(v), DMA and MMA in plant samples that previously received As(v) after being sown and emergence was investigated. Microwave-assisted extraction (MAE) using diluted nitric acid solutions was also performed for arsenic extraction from chicken feed samples. The separation and determination of arsenic species were performed using HPLC-ICP-MS. The interference standard method (IFS) using 83Kr+ as the IFS probe was employed to minimize spectral interferences caused by polyatomic species, such as 40Ar 35Cl+. The extraction procedures tested presented adequate extraction efficiencies (90%), and the four arsenic species evaluated were found in plant samples. Extractions with diluted nitric acid solution at 90 °C were the most efficient strategy, with quantitative recoveries for all four As species in plant tissues. On the other hand, the methanol-water mixture was the solvent with the lowest extraction efficiency (50-60%). For chicken feed samples, MAE at 100 °C for 30 min resulted in an extraction efficiency of 97% and only As(v) was found, without any species interconversion. The IFS method contributed to improving precision and limits of detection and quantification for all tested extraction procedures. Significant improvements on accuracy were obtained by applying the IFS method and recoveries between 77 and 94%, and 82 and 93% were obtained for plant extracts and chicken feed samples, respectively. This journal is © 2013 The Royal Society of Chemistry.

Influencia de metodos y eleccion de un standard en la construccion de una tabla de vida femenina para Guatemala, Honduras y Nicaragua

Incluye Bibliografía

Draft amendments to the standard external trade statistics classification of East Caribbean Common Market Countries

Includes bibliography

Draft standard ECCM trade statistics classification

Includes bibliography

Going through the labyrinth: the political economy of Argentina’s abandonment of the gold standard (1929-1933)

This article is the short but crucial history of four years of transition in a monetary and exchange-rate regime that culminated in 1933 with the final abandonment of the gold standard in Argentina. That process involved decisions made at critical junctures at which the government authorities had little time to deliberate and against which they had no analytical arsenal, no technical certainties and few political convictions. The objective of this study is to analyse those “decisions” at seven milestone moments, from the external shock of 1929 to the submission to Congress of a bill for the creation of the central bank and a currency control regime characterized by multiple exchange rates. The new regime that this reordering of the Argentine economy implied would remain in place, in one form or another, for at least a quarter of a century.

Flow-batch analyser for preparation of calibration standard mixtures in simultaneous multicomponent spectrometric analysis

ABSTRACT: The application of multivariate calibration techniques to multicomponent analysis by UV-VIS molecular absorption spectrometry is a powerful tool for simultaneous determination of several chemical species. However, when this methodology is accomplished manually, it is slow and laborious, consumes high amounts of reagents and samples, is susceptible to contaminations and presents a high operational cost. To overcome these drawbacks, a flow-batch analyser is proposed in this work. This analyser was developed for automatic preparation of standard calibration and test (or validation) mixtures. It was applied to the simultaneous determination of Cu²⁺, Mn²⁺ and Zn²⁺ in polyvitaminic and polymineral pharmaceutical formulations, using 4-(2-piridilazo) resorcinol as reagent and a UV-VIS spectrophotometer with a photodiode array detector. The results obtained with the proposed system are in good agreement with those obtained by flame atomic absorption spectrometry, which was employed as reference method. With the proposed analyser, the preparation of calibration and test mixtures can be accomplished about four hours, while the manual procedure requires at least two days. Moreover, it consumes smaller amounts of reagents and samples than the manual procedure. After the preparation of calibration and test mixtures, 60 samples^-1 can be carried out with the proposed flow-batch analyser.

Search for the standard model Higgs boson produced in association with a W or a Z boson and decaying to bottom quarks

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Organizational safety climate and adherence to standard precautions among dentists

Objective: Check the perception of dentists about safety climate at work in relation to adherence to standard precautions.Methods: It is a quantitative, cross-sectional study conducted through the application of the Safety Climate Scale to a population of 224 dentists who worked in units of primary health care in six municipalities of Parana.Results: The total score of 3.43 (SD = 0.88) reveals that dentists have a poor perception of the incentives and organizational support for adopting standard precautions.Conclusion: Unsatisfactory safety climate, where the perception of dentists about safety in their work environment is deficient, demonstrating fragile management actions of support to safety, lack of a training program in occupational health and deficient feedback to favor the adoption of safe practices.

Search for a non-standard-model Higgs boson decaying to a pair of new light bosons in four-muon final states

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Bismuth as a general internal standard for lead in atomic absorption spectrometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Adherence to standard precautions from the standpoint of the Health Belief Model: the practice of recapping needles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Information access law and disclosing of information by joint-stock companies in Brazil: open data and Extensible Business Reporting Language (XBRL) standard

The strategic management of information plays a fundamental role in the organizational management process since the decision-making process depend on the need for survival in a highly competitive market. Companies are constantly concerned about information transparency and good practices of corporate governance (CG) which, in turn, directs relations between the controlling power of the company and investors. In this context, this article presents the relationship between the disclosing of information of joint-stock companies by means of using XBRL, the open data model adopted by the Brazilian government, a model that boosted the publication of Information Access Law (Lei de Acesso à Informação), nº 12,527 of 18 November 2011. Information access should be permeated by a mediation policy in order to subsidize the knowledge construction and decision-making of investors. The XBRL is the main model for the publishing of financial information. The use of XBRL by means of new semantic standard created for Linked Data, strengthens the information dissemination, as well as creates analysis mechanisms and cross-referencing of data with different open databases available on the Internet, providing added value to the data/information accessed by civil society.