Determination of Cd, Cr and Pb in phosphate fertilizers by laser-induced breakdown spectroscopy

Determination of Cd, Cr and Pb in phosphate fertilizers by laser-induced breakdown spectroscopy

Author Nunes, Lidiane Cristina Google Scholar
Arantes de Carvalho, Gabriel Gustinelli Google Scholar
Santos Junior, Dario Autor UNIFESP Google Scholar
Krug, Francisco Jose Google Scholar
Institution Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Abstract A validated method for quantitative determination of Cd, Cr, and Pb in phosphate fertilizers by laser-induced breakdown spectroscopy (LIBS) is presented. Laboratory samples were comminuted and homogenized by cryogenic or planetary ball milling, pressed into pellets and analyzed by LIBS. the experimental setup was designed by using a Q-switched Nd:YAG at 1064 nm with 10 Hz repetition rate, and the intensity signals from Cd II 214.441 nm, Cr II 267.716 nm and Pb II 220.353 nm emission lines were measured by using a spectrometer furnished with an intensified charge-coupled device. LIBS parameters (laser fluence, lens-to-sample distance, delay time, integration time gate, number of sites and number of laser pulses per site) were chosen after univariate experiments with a pellet of NIST SRM 695 (Trace Elements in Multi-Nutrient Fertilizer). Calibration and validation were carried out with 30 fertilizer samples from single superphosphate, triple superphosphate, monoammonium phosphate, and NPK mixtures. Good results were obtained by using 30 pulses of 50 J cm(-2) (750 mu m spot size), 2.0 mu s delay time and 5.0 mu s integration time gate. No significant differences between Cd, Cr, and Pb mass fractions determined by the proposed LIBS method and by ICP OES after microwave-assisted acid digestion (AOAC 2006.03 Official Method) were found at 95% confidence level. the limits of detection of 1 mg kg(-1) Cd, 2 mg kg(-1) Cr and 15 mg kg(-1) Pb and the precision (coefficients of variation of results ranging from 2% to 15%) indicate that the proposed LIES method can be recommended for the determination of these analytes in phosphate fertilizers. (C) 2014 Elsevier B.V. All rights reserved.
Keywords Laser-induced breakdown spectroscopy
Phosphate fertilizers
Cadmium
Chromium
Lead
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Grant number FAPESP: 2010/17158-8
FAPESP: 2010/16379-0
CNPq: 482500/2011-5
CNPq: 305913/2009-3
CNPq: 578728/2008-7
CNPq: 309800/2011-0
CNPq: 482499/2012-5
Date 2014-07-01
Published in Spectrochimica Acta Part B-atomic Spectroscopy. Oxford: Pergamon-Elsevier B.V., v. 97, p. 42-48, 2014.
ISSN 0584-8547 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 42-48
Origin http://dx.doi.org/10.1016/j.sab.2014.04.011
Access rights Closed access
Type Article
Web of Science ID WOS:000339534100005
URI http://repositorio.unifesp.br/handle/11600/37948

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