Laser Induced Breakdown Spectroscopy

This review describes the fundamentals, instrumentation, applications and future trends of an analytical technique that is in its early stages of consolidation and is establishing its definitive niches among modern spectrometric techniques. The technique has been named Laser Induced Breakdown Spectroscopy (LIBS) and its main characteristic stands in the use of short laser pulses as the energy source to vaporize samples and excite the emission of electromagnetic radiation from its elements and/or molecular fragments. The emitted radiation is analyzed by high resolution optics and the intensities are recorded, usually by fast triggered solid state detectors. Together, these devices allow producing and registering a wide ranging emission spectrum of the short-lived phenomenon induced by the laser pulse. The spectrum contains qualitative and quantitative information which can be correlated with sample identity or can be used to determine the amount of its constituents. This review is divided in four parts. First, the relevant historical and theoretical concepts associated with LIBS are presented; then the main practical aspects of the several experimental and instrumental approaches employed for implementation of the technique are critically described; the applications related in the literature, including those making use of chemometrics, are classified and exemplified with relevant and recently published work. Finally, an attempt to portray an overall evaluation and future perspectives of the technique are presented.Esta revisão descreve os aspectos fundamentais, a instrumentação, as aplicações e tendências futuras de uma técnica analítica que se encontra em seu estágio de consolidação e que está em vias de estabelecer o seu nicho entre as técnicas espectrofotométricas modernas. A técnica é denominada Espectroscopia de Emissão em Plasma Induzido por Laser (em inglês, Laser Induced Breakdown Spectroscopy, LIBS) e sua principal característica está no uso de pulsos de laser como fonte de energia para vaporizar a amostra e excitar a emissão de radiação eletromagnética, a partir de seus elementos e/ou fragmentos moleculares. A radiação emitida é analisada por meio de instrumentos ópticos de alta resolução e as suas intensidades são medidas, usualmente com detectores rápidos de estado sólido. Em conjunto, esses dispositivos permitem a geração e a medida de um espectro de emissão de faixa ampla do fenômeno induzido pelo pulso de laser. O espectro registrado contém informação qualitativa e quantitativa que pode ser correlacionada com a identidade da amostra ou empregada na determinação da quantidade de seus constituintes. Essa revisão é dividida em quatro partes. A primeira aborda aspectos históricos da técnica e os conceitos teóricos relevantes associados com LIBS; então, os aspectos práticos de diversas abordagens experimentais e instrumentais empregadas na implementação da técnica são revistos de forma crítica; as aplicações encontradas na literatura, incluindo aquelas que empregam quimiometria, são classificadas e exemplificadas por meio de trabalhos relevantes recentemente publicados. Finalmente, uma tentativa de estabelecer uma avaliação global e as perspectivas futuras para a técnica é apresentada.463512Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Laser Induced Breakdown Spectroscopy

This review describes the fundamentals, instrumentation, applications and future trends of an analytical technique that is in its early stages of consolidation and is establishing its definitive niches among modern spectrometric techniques. The technique has been named Laser Induced Breakdown Spectroscopy (LIBS) and its main characteristic stands in the use of short laser pulses as the energy source to vaporize samples and excite the emission of electromagnetic radiation from its elements and/or molecular fragments. The emitted radiation is analyzed by high resolution optics and the intensities are recorded, usually by fast triggered solid state detectors. Together, these devices allow producing and registering a wide ranging emission spectrum of the short-lived phenomenon induced by the laser pulse. The spectrum contains qualitative and quantitative information which can be correlated with sample identity or can be used to determine the amount of its constituents. This review is divided in four parts. First, the relevant historical and theoretical concepts associated with LIBS are presented; then the main practical aspects of the several experimental and instrumental approaches employed for implementation of the technique are critically described; the applications related in the literature, including those making use of chemometrics, are classified and exemplified with relevant and recently published work. Finally, an attempt to portray an overall evaluation and future perspectives of the technique are presented

Avaliação de laboratórios brasileiros na determinação de alguns parâmetros de qualidade de biocombustíveis

This work shows the results of a Proficiency Testing performed by a partnership between INMETRO and ANP. The performance of 49 Brazilian laboratories (using the z-score statistical test) in determining 10 quality parameters of ethanol fuel and biodiesel was evaluated. The certified reference values were provided by INMETRO, allowing a more rigorous assessment of the laboratories. For hydrous ethanol, the acidity parameter showed the lowest number of laboratories with satisfactory results (48%), while 85% of the laboratories presented satisfactory results for ethanol content. For biodiesel, the percentage of laboratories with satisfactory results ranged from 46% (kinematic viscosity) to 92% (acid number)

Avaliação de laboratórios brasileiros na determinação de alguns parâmetros de qualidade de biocombustíveis Evaluation of Brazilian laboratories for determining quality parameters of biofuels

This work shows the results of a Proficiency Testing performed by a partnership between INMETRO and ANP. The performance of 49 Brazilian laboratories (using the z-score statistical test) in determining 10 quality parameters of ethanol fuel and biodiesel was evaluated. The certified reference values were provided by INMETRO, allowing a more rigorous assessment of the laboratories. For hydrous ethanol, the acidity parameter showed the lowest number of laboratories with satisfactory results (48%), while 85% of the laboratories presented satisfactory results for ethanol content. For biodiesel, the percentage of laboratories with satisfactory results ranged from 46% (kinematic viscosity) to 92% (acid number)