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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Determinations of phosphorus in fertilizers by spark discharge-assisted laser-induced breakdown spectroscopy

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Author(s):
Vieira, Alan Lima [1] ; Silva, Tiago Varao [1] ; Inocencio de Sousa, Felipe Schiavon [2] ; Senesi, Giorgio Saverio [3] ; Santos Junior, Dario [4] ; Ferreira, Edilene Cristina [1] ; Gomes Neto, Jose Anchieta [1]
Total Authors: 7
Affiliation:
[1] Sao Paulo State Univ UNESP, Analyt Chem Dept, POB 355, BR-14801970 Araraquara, SP - Brazil
[2] Univ Sao Paulo, Dept Elect & Comp Engn, BR-13566590 Sao Carlos, SP - Brazil
[3] CNR, Ist Nanotecnol NANOTEC, PLasMI Lab, Via Amendola 122-D, I-70126 Bari - Italy
[4] Fed Univ Sao Paulo UNIFESP, Exact & Earth Sci Dept, BR-09913030 Diadema, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: Microchemical Journal; v. 139, p. 322-326, JUN 2018.
Web of Science Citations: 7
Abstract

A spark discharge system was coupled to laser-induced breakdown spectroscopy (SD-LIBS) to improve sensitivity in the determination of P in fertilizers. A LIBS system consisting of a Q-switched Nd:YAG laser operating at 1064 nm and emitting pulses at 50 mJ with a fluence of 70 J cm(-2) at the focal point was used. Results of preliminary experiments suggested that the most appropriate wavelength to measure P was the P (1) line at 214.9 nm, which did not show interferences by Fe, Cu and Zn. The electrical discharge was provided by a homemade high-voltage electronic circuit consisting of two cylindrical tungsten electrodes at the optimized output voltage of 4.5 kV, with tips arranged at the optimal distances of 4 mm between them and 2 mm above the sample surface. To minimize the expected matrix effects calibration standards of P2O5 in the range of 4.8 and 33.3% were prepared by mixing various amounts of a phosphate rock reference material (SRM-120c) with a mixture of CaCO3, CaSO4, (NH2)(2)CO and KCl at a 1:1:1:1 mass ratio. The calibration curves obtained at a 4.5 kV SD-LIBS output voltage showed correlation coefficients RSD <= 8% and LOQ5.3% (m/m) P2O5. Data obtained by analyzing commercial samples by the proposed system were in good agreement, at 95% confidence level, with those obtained by using high-resolution continuum-source flame atomic absorption spectroscopy. (C) 2018 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 15/24757-9 - LIBS technique evaluation for Ca, K, P and N determination in new smart sustainable fertilizers
Grantee:Edilene Cristina Ferreira
Support Opportunities: Regular Research Grants