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Oliveira EM, Ferreira EC, Gomes Neto JA, Donati GL, Jones BT. Raman spectroscopy coupled to high-resolution continuum source flame molecular absorption spectrometry for sequential determination of nitrogen species in fertilizers. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 283:121737. [PMID: 35964351 DOI: 10.1016/j.saa.2022.121737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/02/2022] [Accepted: 08/06/2022] [Indexed: 06/15/2023]
Abstract
Raman spectroscopy (RS) was used to identify and quantify different nitrogen species in fertilizers. This is a fast and inexpensive method that requires no extensive sample preparation. Urea and nitrate were determined at 1000 and 1045 cm-1, respectively. Calibration plots obtained for these analytes showed adequate linearity, with regression coefficients (r) of 0.9989 and 0.9976, respectively. Ammonium was determined by difference after total N determination by high-resolution continuum source flame molecular absorption spectrometry (HR-CS FMAS), which provided a calibration plot with r = 0.9960. The inline coupling of RS and HR-CS FMAS allowed for a fast sequential determination of ammonium, nitrate, and urea, with limits of detection of 0.03 mg/L ammonium, 0.03 mg/L nitrate, and 0.01 mg/L urea. Relative standard deviations were ≤ 11 %, and the external standard calibration method provided accurate results for all analytes determined in certified reference materials, raw materials, and commercial samples of fertilizers. For comparison purposes, all samples were also analyzed by traditional Kjeldahl method. The RS HR-CS FMAS method was further validated by addition and recovery experiments, which provided recoveries in the 93 - 113 % range.
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Affiliation(s)
- Evilim M Oliveira
- Institute of Chemistry, São Paulo State University (UNESP), Araraquara City 14800-060, São Paulo State, Brazil
| | - Edilene C Ferreira
- Institute of Chemistry, São Paulo State University (UNESP), Araraquara City 14800-060, São Paulo State, Brazil
| | - José A Gomes Neto
- Institute of Chemistry, São Paulo State University (UNESP), Araraquara City 14800-060, São Paulo State, Brazil.
| | - George L Donati
- Department of Chemistry, Wake Forest University, Salem Hall, Box 7486, Winston-Salem, NC 27109, USA
| | - Bradley T Jones
- Department of Chemistry, Wake Forest University, Salem Hall, Box 7486, Winston-Salem, NC 27109, USA
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de Jesus ET, Moreira AJ, Sá MC, Freschi GPG, Joya MR, Li MS, Paris EC. Potential of Nb 2O 5 nanofibers in photocatalytic degradation of organic pollutants. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:69401-69415. [PMID: 34302247 DOI: 10.1007/s11356-021-15435-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/09/2021] [Indexed: 06/13/2023]
Abstract
Various photocatalytic nanomaterials for environmental remediation have been promoted due to the pollution caused by different organic pollutants. In this study, Nb2O5 nanofibers were obtained by electrospinning technique, presenting controlled crystallinity and high specific surface area to improve the photoactivity response. The structural characterization indicated Nb2O5 nanofibers with orthorhombic phase formation. The photoluminescence measurements showed different energy levels contributing to the electronic transition events. The nanofibers with a bandgap up to 3.6 eV were applied to photocatalysis of dyes (rhodamine B (RhB) or methylene blue (MB)) and fluoxetine (FLX), listed as an emergent pollutant. In the optimized condition (pH = 9), the RhB and MB photocatalysis was 59% and 93% more efficient than photolysis due to ζ = - 50 mV ± 5 for EtOH_550 sample increased interaction with MB (cationic) compared to RhB unprotonated (pKa = 3.7). Therefore, FLX (pKa = 10.7) was selected due to protonated form at pH = 9 and showed 68% ± 1 adsorption in 30 min for EtOH_550. The FLX photocatalytic degradation under UV light irradiation was up to 17% higher than the photolytic degradation. The formation of hydroxyl radicals in the photocatalytic system (EtOH_550) was proven by the Coumarine probe assay, corroborating with the greater amount of α-[2-(methylamino)ethyl]benzylalcohol (MAEB), a by-product obtained after FLX oxidation. Additionally, the material achieved specific catalytic activity for the different organic compounds (RhB, MB, or FLX). Therefore, Nb2O5 nanofibers were efficient for degrading three different pollutants under UV light, proving a viable alternative for environmental remediation.
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Affiliation(s)
- Edson Tobias de Jesus
- Nanotechnology National Laboratory for Agriculture (LNNA), Embrapa Instrumentação, XV de Novembro St., 1452, zip code, São Carlos, SP, 13560-970, Brazil
- Department of Chemistry, Federal University of São Carlos, Rod. Washington Luiz, km 235, zip code, São Carlos, SP, 13565-905, Brazil
- Federal Institute of Education, Science and Technology of Maranhão, Baronesa street, zip code, Alcântara, MA, 65250-000, Brazil
| | - Ailton José Moreira
- Department of Chemistry, Federal University of São Carlos, Rod. Washington Luiz, km 235, zip code, São Carlos, SP, 13565-905, Brazil
- LAFFEQ, Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil
| | - Mayara Coelho Sá
- Nanotechnology National Laboratory for Agriculture (LNNA), Embrapa Instrumentação, XV de Novembro St., 1452, zip code, São Carlos, SP, 13560-970, Brazil
- Department of Chemistry, Federal University of São Carlos, Rod. Washington Luiz, km 235, zip code, São Carlos, SP, 13565-905, Brazil
- Federal Institute of Education, Science and Technology of Maranhão, Baronesa street, zip code, Alcântara, MA, 65250-000, Brazil
| | - Gian Paulo Giovanni Freschi
- LAFFEQ, Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil
| | - Miryam Rincón Joya
- Departamento de Física, Universidad Nacional de Colombia, Calle 45 #30-03, Bogotá, C.P. 111321, Colombia
| | - Maximo Siu Li
- Institute of Physics, University of São Paulo, São Carlos, SP, 13563-120, Brazil
| | - Elaine Cristina Paris
- Nanotechnology National Laboratory for Agriculture (LNNA), Embrapa Instrumentação, XV de Novembro St., 1452, zip code, São Carlos, SP, 13560-970, Brazil.
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Moreira AJ, Freschi CD, Pereira EC, Freschi GPG. N-compounds speciation analysis in environmental samples using ultrasound-assisted solid-liquid extraction and non-chromatographic techniques. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:297. [PMID: 33893885 DOI: 10.1007/s10661-021-09088-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 04/19/2021] [Indexed: 06/12/2023]
Abstract
A fast, efficient, and non-chromatographic method was presented in this study for nitrite, nitrate, and p-nitrophenol (N-compounds) extraction and speciation analysis of environmental samples. By applying ultrasound-assisted solid-liquid extraction (USLE), analytes were efficiently extracted from water, soil, or sediment collected in areas of environmental disaster. These analytes were selectively converted to NO(g) through UV photolysis (NO3-), H2O2/UV photocatalysis (PNP), and direct conversion (NO2-). Following conversion, NO(g) was separated from the liquid phase and determined by high-resolution continuum source molecular absorption spectrometry (HR-CS MAS). The LODs obtained were 0.097 ± 0.004 mg L-1 for nitrite, 0.119 ± 0.004 mg L-1 for nitrate, and 0.090 ± 0.006 mg L-1 for p-nitrophenol. On applying this speciation method to environmental samples, concentrations were found to be up to 0.99 ± 0.03 mg L-1 (NO2-), 49.80 ± 2.5 mg L-1 (NO3-), and 0.10 ± 0.02 mg L-1 (PNP). Finally, addition/recovery study of real water, soil, and sediment samples showed 101 ± 2% recovery for NO2-, 100 ± 1% for NO3-, and 96 ± 5% for PNP.
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Affiliation(s)
- Ailton José Moreira
- LAFFEQ, Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil.
- Chemistry Dept, Universidade Federal de São Carlos, UFSCar-SP, São Carlos, SP, 13565-905, Brazil.
| | - Carolina Dakuzaku Freschi
- LAFFEQ, Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil
| | - Ernesto Chaves Pereira
- Chemistry Dept, Universidade Federal de São Carlos, UFSCar-SP, São Carlos, SP, 13565-905, Brazil
| | - Gian Paulo Giovanni Freschi
- LAFFEQ, Institute of Science and Technology, Federal University of Alfenas, UNIFAL-MG, Poços de Caldas, MG, 37715-400, Brazil
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Resano M, Aramendía M, Nakadi FV, García-Ruiz E, Alvarez-Llamas C, Bordel N, Pisonero J, Bolea-Fernández E, Liu T, Vanhaecke F. Breaking the boundaries in spectrometry. Molecular analysis with atomic spectrometric techniques. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.115955] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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