Influence of particle size distribution on the analysis of pellets of plant materials by laser-induced breakdown spectroscopy

Autor(es)

Arantes de Carvalho, Gabriel Gustinelli ; Santos, Dario, Jr. ; Gomes, Marcos da Silva ; Nunes, Lidiane Cristina ; Bueno Guerra, Marcelo Braga ; Krug, Francisco Jose

• Tipo de documento: Artigo Científico
• Fonte: SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY; v. 105, p. 6-pg., 2015-03-01.

Resumo

Pellets of sieved plant materials (150, 106, 75,53 and 20 pm sieve apertures) were prepared and analyzed by laser-induced breakdown spectroscopy (LIBS), and the results for Ca, K, Mg, P, B and Mn were discussed as a function of particle size distribution. This parameter is of key importance for appropriate test sample presentation in the form of pressed pellets for quantitative analysis by LIBS. Experiments were carried out with a Q-switched Nd:YAG laser at 1064 nm, and a spectrometer with Echelle optics and an intensified charge-coupled device. Results indicated that smaller particles yielded up to 50% emission signal intensities' enhancement and attained better measurements' precision (site-to-site variation). Moreover, matrix effects were reduced by analyzing pellets prepared from <75 mu m sieved fractions (mean particle size = 32 mu m; d(95) = 102 mu m) and by using a 50 J cm(-2) laser fluence (220 mJ per pulse; 750 mu m laser spot size). The preparation of pellets from laboratory samples with monomodal particle size distributions, where most particles were smaller than 100 mu m, was decisive for improving analyte micro-homogeneity within the test samples and for attaining lower coefficients of variation of measurements, typically lower than 10% (n = 10 sites per pellet; 20 laser pulses per site). (C) 2014 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 10/17158-8 - Avaliação da espectrometria de emissão óptica com plasma induzido por laser (LIBS) para determinação de contaminantes inorgânicos em fertilizantes agrícolas
• Beneficiário: Lidiane Cristina Nunes
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 12/16203-5 - Estratégias para análise direta de folhas de cana-de-açúcar por espectrometria de emissão óptica com plasma induzido por laser (LIBS)
• Beneficiário: Marcelo Braga Bueno Guerra
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 10/16379-0 - Estratégias de microamostragem para a análise de tecidos biológicos por espectrometria de emissão óptica com plasma induzido por laser
• Beneficiário: Gabriel Gustinelli Arantes de Carvalho
• Modalidade de apoio: Bolsas no Brasil - Doutorado