INTRODUCTION

Given their chemical and physical complexity, pushing the frontiers of knowledge in earth sciences requires the constant support of high quality quantitative chemical data. Therefore, geochemistry and its several subdivisions becomes an invaluable tool in geological investigation. Environmental research is a particularly challenging multidisciplinary subject, requiring increasingly more refined methods to produce accurate chemical data from ever lower concentration levels. In addition, modern research techniques in whole-rock, soil and mineral chemistry have increasingly demanded the analysis of elements in trace and ultra-trace concentrations. State-of-the-art equipment is of paramount importance in this scenario. The aim of the Geochemistry Laboratory is to meet these requirements.

STAFF

Academic Staff

• Dr. Geraldo R. Boaventura - Head of LAGEQ
• Dr. José Affonso Brod

Technical Staff

• Fernando Souza Cavalcante
• Antônio Fortes P. Filho

In addition to the permanent staff, the Laboratory is actively engaged in collaborative research with other academic members of the IG/UnB and post-graduate students. Undergraduates and trainees are also closely involved in the activities of LAGEQ. A number of collaborative research programs with other Departments at University of Brasília, and with national and international research institutions are currently in progress.

ACTIVITIES

LAGEQ provides high-quality chemical analyses of a range of geologic materials to support research and teaching activities of staff and students at the IG-UnB. New analytical methods and techniques applied to the geosciences are also the subject of continuous research within the Laboratory. The main research areas of the permanent staff at LAGEQ are environmental geochemistry, analytical geochemistry, analytical chemistry and geochemistry applied to petrology and mineralogy.

SAMPLE PREPARATION FACILITIES

LAGEQ premises comprise an area of approximately 300 m², in the Central Institute of Sciences (ICC, module CSS-406) of the University of Brasília. Some of the facilities offered include:

• Sample preparation room, containing 3 jaw-crushers, 2 hydraulic splitters, agate and carbide mills, sampling devices, sieves and other equipment to guarantee a continuous flow of samples for analysis.
• Weighing room, including analytical balances METLER, AE 163 e AE 240, with accuracy down to one hundredth of a milligram.
• Laboratory facilities for sample digestion and analysis, including 4 fume cupboards, 4 distilled water devices, MILI-Q system for production of high-purity water (18,2 MW cm^-1), furnaces, hot plates and all ordinary laboratory equipments and reagents required for preparation of various kinds of geological samples.
• Laboratory for analysis of water, including capability for determination of physicochemical parametres and preparation of water samples for analyses of metal content.
• Microwave digestion system SPEX CDS 7000.

INSTALLED ANALYTICAL EQUIPMENT

1. UV Visible spectrophotometer
2. Flame photometer
3. Atomic Absorption Spectrophotometer Perkin Elmer model 403
4. Atomic Absorption Spectrophotometer Perkin Elmer model 603, equiped with a graphite furnace
5. LECO carbon and sulphur analysers
6. Atomic Emission Spectrometer with Inductively Coupled Plasma source (ICP-AES), SPECTRO FMV03
7. Mercury analyser SPECTROMERC
8. High resolution magnetic sector Mass Spectrometer with Inductively Coupled Plasma source (ICP/MS) FININGAN-MAT-ELEMENT, equipped with a Laser Ablation Microprobe (LAM) system.

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   Atomic Absortion Spectrofotometer 

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   Mercury analyser

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   Plasma source atomic emission spectrometer  

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   Plasma source mass spectrometer

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ANALYTICAL TECHNIQUES

Routine analytical methods are installed at LAGEQ for the analyses of over 40 elements in rocks, minerals, ores, soil, sediment, water and other materials of interest to the earth and/or environmental sciences. Most applications are devoted to the analyses of major and trace elements by AAS, ICP/AES and ICP/MS, with emphasis on simultaneous, multi-element analyses (up to 25 elements in the ICP/AES and up to 40 elements with the ICP/MS) carried out on a single sample and to the punctual analyses of "in natura" materials by the LAM-ICP-MS system. Classic methods such as colorimetric, gravimetric and volumetric analyses are also used for specific applications.

SERVICES AVAILABLE

The following services are available to LAGEQ users, inside and outside the University:

• Qualitative and quantitative chemical analysis
• Analysis of geological and biological material
• Analysis of metals
• Analysis of water

In view of the available facilities and equipment, participation in other projects on request is possible, particularly the determination of metals in various matrices. Please send enquiries to the address below

QUALITY CONTROL

Chemical data produced at LAGEQ are meticulously controlled through the systematic analysis of reference samples, duplicates and blanks, in order to guarantee strict control over the quality of the results. The accuracy and precision of analyses are further monitored by internally prepared standards.

ADDRESS

UNIVERSIDADE DE BRASÍLIA
INSTITUTO DE GEOCIÊNCIAS
DEPARTAMENTO DE GEOQUÍMICA E RECURSOS MINERAIS
CAMPUS UNIVERSITÁRIO DARCY RIBEIRO
70.910-900 BRASÍLIA -DF - BRAZIL

PHONES - (+55) 61 307.2391
FAX - (+55) 61 2724286 and 61 3474062
e-mail: grbunb@unb.br

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Institute of Geosciences/University of Brasília