Flow-through cell based on an array of gold microelectrodes obtained from modified integrated circuit chips

The construction of a flow-through cell incorporating an array of gold microelectrodes is described and its application to flow injection analysis with amperometric detection is presented, Simple modification of almost any conventional integrated circuit chip, used as an inexpensive source of pre-assembled gold micro-wires, leads to the rapid and successful preparation of arrays of 8-48 elements, the polymeric encapsulation material from the top face of the chip is removed by abrasion until the gold micro-mires (used to interconnect the silicon circuit to the external contact pins of the chip) are disrupted and their transversal (elliptical) sections become exposed. Once polished, the flat and smooth top surface of the gold microelectrode-array chip (MEAC) is provided with a spacer and fitted under pressure against an acrylic block with the reference and auxiliary electrodes, to form the electrochemical (thin-layer) flow cell, while the contact pins are plugged into a standard IC socket, This design ensures autonomous electric contact with each electrode and allows fast dismantling for polishing or substitution, the performance of flow cells with MEACs was investigated utilizing the technique of reverse pulse amperometry without oxygen removal, A method was established for the determination of the copper concentration in sugar cane spirit, regulated by law for beverages, Samples from industrial producers and small-scale (alembic) brewers were compared, With a 24 MEAC, a detection limit of 30 mu g I-l of copper (4.7 x 10(-7) mol l(-1) of Cu-II for 100 mu l injections) was calculated, Routine operation was established at a frequency of 60-90 determinations per hour, Intercomparison with atomic absorption spectrometric determinations resulted in excellent agreement.

O apoiador caipira: o desafio/arte de articular redes regionais de saúde a partir de territórios/desejos singulares

Pós-graduação em Psicologia - FCLAS

Tutela penal e teoria crítica de direitos humanos: uma intersecção crítico-dialética marginal

Pós-graduação em Direito - FCHS

Reestruturação produtiva e trabalho bancário no Brasil: crise, rupturas e fetiche no caso das demissões voluntárias no Banespa

Pós-graduação em Ciências Sociais - FFC

Política educacional paulista (1995-2012): dos primórdios da reforma empresarial neoliberal à consolidação do modelo gerencial

Pós-graduação em Educação - FFC

Sociedade, estado e organizações não governamentais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mulheres que tecem a vida: trabalho e gênero em tempos precarizados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

As Praças Centrais de Presidente Prudente-SP: avaliação do caráter como subsídio para intervenções projetuais

During the process of development and urban sprawl in the city of Presidente Prudente (SP), some factors as the emergence of new centralities, the change in lifestyles and the expansion of equipments and urban infrastructure contributed to the dismantling and little appropriation of the central open space system. In this sense, the work is about the loss of continuity between the central squares of the city - Monsenhor Sarrion Square, July 9 Square, Bandeira Square and Nossa Senhora Aparecida Square - using different methodologies for character evaluation of each square, identifying the inviting and unattractive aspects of their spaces. The relations between these squares and its surroundings are characterized by analyzing interesting visual played on sketches, to complement character evaluation. Among these studies, it is also analyzed two spatial structures related to the squares – Calçadão and Quintino Bocaiuva Street - which have important architectural referring to the city's history and contribute to the central open space system configuration. General considerations obtained through diagnosis provided subsidies for the projectual proposed intervention, which aims to provide appreciation of the character of these public spaces and their articulation, promoting their use and constituting, thus, an important urban-environment set

El Salvador: da guerra civil às reformas institucionais dos anos 1990

Pós-graduação em História - FCHS

Sobre graça, dignidade e beleza em Friedrich Schiller e Heinrich von Kleist

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A política brasileira de exportação de armas no contexto da revitalização da base industrial de defesa

Pós-graduação em Relações Internacionais (UNESP - UNICAMP - PUC-SP) - FFC