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Boudissa F, Arus VA, Foka-Wembe EN, Zekkari M, Ouargli-Saker R, Dewez D, Roy R, Azzouz A. Role of Silica on Clay-Catalyzed Ozonation for Total Mineralization of Bisphenol-A. Molecules 2023; 28:molecules28093825. [PMID: 37175235 PMCID: PMC10179811 DOI: 10.3390/molecules28093825] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023] Open
Abstract
Catalytic ozonation for the total mineralization of bisphenol-A (BPA) from aqueous solution was investigated in the presence of various silica-based catalysts such as mesoporous silica, acid-activated bentonite (HMt) and montmorillonite-rich materials (Mt) ion-exchanged with Na+ and Fe2+ cations (NaMt and Fe(II)Mt). The effects of the catalyst surface were studied by correlating the hydrophilic character and catalyst dispersion in the aqueous media to the silica content and BPA conversion. To the best of our knowledge, this approach has barely been tackled so far. Acid-activated and iron-free clay catalysts produced complete BPA degradation in short ozonation times. The catalytic activity was found to strongly depend on the hydrophilic character, which, in turn, depends on the Si content. Catalyst interactions with water and BPA appear to promote hydrophobic adsorption in high Si catalysts. These findings are of great importance because they allow tailoring silica-containing catalyst properties for specific features of the waters to be treated.
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Affiliation(s)
- Farida Boudissa
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, Montreal, QC H3C 3P8, Canada
| | - Vasilica-Alisa Arus
- Catalysis and Microporous Materials Laboratory, Vasile Alecsandri University of Bacau, 600115 Bacau, Romania
| | - Eric-Noel Foka-Wembe
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, Montreal, QC H3C 3P8, Canada
| | - Meriem Zekkari
- Department of Materials Engineering, University of Science and Technology, El M'naouer, B.P. 1505, Bir El Djir, Oran 31000, Algeria
| | - Rachida Ouargli-Saker
- Department of Materials Engineering, University of Science and Technology, El M'naouer, B.P. 1505, Bir El Djir, Oran 31000, Algeria
| | - David Dewez
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, Montreal, QC H3C 3P8, Canada
| | - René Roy
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, Montreal, QC H3C 3P8, Canada
| | - Abdelkrim Azzouz
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, Montreal, QC H3C 3P8, Canada
- École de Technologie Supérieure, Montreal, QC H3C 1K3, Canada
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Su H, Shi S, Zhu M, Li J, Su G. Liquid Crystal Monomers (LCMs) in Sediments: Method Validation and Detection in Sediment Samples from Three Typical Areas. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:2336-2345. [PMID: 33528249 DOI: 10.1021/acs.est.0c06427] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Liquid crystal monomers (LCMs) have been proposed to be persistent, bioaccumulative, and toxic (PBT) substances; however, there is a dearth of information regarding their occurrence in sediment samples. Here, an analytical method was developed for the quantitative determination of LCMs in sediment samples, and n = 76 sediment samples were collected and analyzed to determine accurate concentrations of LCMs. Our results indicated that the developed pretreatment procedure was applicable for the determination of LCM concentrations in sediments. We observed that LCMs were detected in 75 out of the 76 sediment samples, and 23, 18, and 14 out of the 39 target LCMs were quantified in at least one of the analyzed sediments from rivers around LCM or liquid crystal device (LCD) manufacturers, Taihu Lake, and rivers around e-waste recycling sites, respectively. The LCMs in the samples from rivers around LCM/LCD manufacturers exhibited the greatest mean concentrations of 26.1 ng/g dry weight (dw), followed by those from e-waste recycling site areas (1.15 ng/g dw) and Taihu Lake (0.076 ng/g dw). Collectively, this study provided the first analytical method that was able to quantify the concentrations of LCMs in sediment samples and provided the first evidence for the occurrence of LCMs in sediment samples.
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Affiliation(s)
- Huijun Su
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China
| | - Shaobo Shi
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China
| | - Ming Zhu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China
| | - Jianhua Li
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China
| | - Guanyong Su
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China
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Boudissa F, Mirilà D, Arus VA, Terkmani T, Semaan S, Proulx M, Nistor ID, Roy R, Azzouz A. Acid-treated clay catalysts for organic dye ozonation - Thorough mineralization through optimum catalyst basicity and hydrophilic character. JOURNAL OF HAZARDOUS MATERIALS 2019; 364:356-366. [PMID: 30384246 DOI: 10.1016/j.jhazmat.2018.09.070] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 06/08/2023]
Abstract
Catalytic ozonation of Methylene Blue, Methyl Green, Methyl Orange and Methyl-thymol Blue was investigated in the presence of ion-exchanged montmorillonite (NaMt and Fe(II)Mt), crude bentonite and acid-activated counterparts. An original approach never tackled so far consisted in correlating the basicity and hydrophilic character to the dye-catalyst interactions occurring on the catalyst surface. This was achieved through CO2 and water thermal programmed desorption. Kinetics study revealed that ozonation starts in the bulk solution, and dye adsorption turns out to be an essential requirement for high catalytic effectiveness. On NaMt, dye molecules appear to adsorb mainly via hydrophobic interaction. On Fe(II)Mt, the contributions of hydrophobic interaction, cation-exchange and Fe2+ mobility to the catalytic activity prevail. Acid activated clay catalysts exhibited lowest hydrophilic character favoring adsorption through organophilic interaction and affording thorough and fast dye mineralization. This was explained in terms of increased number of silanols and -Si-O-Si- groups. For all catalysts, short ozonation of all dye molecules resulted in similar end-chain products, which were totally eliminated after prolonged reaction times. This result is of great importance because it provides valuable theoretical findings that allow envisaging total mineralization of organic molecules by recyclable metal-free clay catalysts.
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Affiliation(s)
- Farida Boudissa
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8, Canada
| | - Diana Mirilà
- Catalysis and Microporous Materials Laboratory, Vasile-Alecsandri University of Bacau, Romania
| | - Vasilica-Alisa Arus
- Catalysis and Microporous Materials Laboratory, Vasile-Alecsandri University of Bacau, Romania
| | - Thizizi Terkmani
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8, Canada
| | - Sirène Semaan
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8, Canada
| | - Mélanie Proulx
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8, Canada
| | - Ileana-Denisa Nistor
- Catalysis and Microporous Materials Laboratory, Vasile-Alecsandri University of Bacau, Romania
| | - René Roy
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8, Canada
| | - Abdelkrim Azzouz
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, QC, H3C 3P8, Canada.
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Benhamouda K, Belaidi S, Sehili T, Djebbar K. Catalytic Photodegradation of Rhodamine B in the Presence of Natural Iron Oxide and Oxalic Acid under Artificial and Sunlight Radiation. INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING 2017. [DOI: 10.1515/ijcre-2016-0027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractNatural iron oxide was used as catalyst for a heterogeneous photo-Fenton-like process and it was characterized by X-ray diffraction, X-ray fluorescence, Raman spectroscopy, scanning electron microscopy and N2adsorption volumetry measurement. Natural iron oxide consists mainly of hematite (76 %). Rhodamine B was mineralized by iron oxide/oxalic acid/UV system, involving creation of dissolved Fe-oxalate and adsorption of Fe-oxalate on the iron oxide surface. The effects of the initial concentration of oxalic acid and pH value, amount of natural iron oxide and concentration of dye, temperature and sunlight irradiation on the kinetics of photodegradation of rhodamine B were investigated. Excellent degradation rate was achieved with 5 mmol.L−1of oxalic acid at a pH around 2–4. During the process, the formation of Fe2+, H2O2and the pH of the solution were strongly dependent on the initial concentration of oxalic acid. Use oft-butanol (2.0 %) confirms that hydroxyl radicals are the entities responsible for the rhodamine B photodegradation. The use of the natural iron oxide as a catalyst in wastewater treatment is very interesting; because it is an abundant mineral and easy to separate from the solution in the end of treatment.
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Affiliation(s)
- K. Benhamouda
- Laboratory of Sciences and Technologies of the Environment (LSTE), University of Constantine, Constantine, Algeria
| | - S. Belaidi
- Laboratory of Sciences and Technologies of the Environment (LSTE), University of Constantine, Constantine, Algeria
| | - T. Sehili
- Laboratory of Sciences and Technologies of the Environment (LSTE), University of Constantine, Constantine, Algeria
| | - K. Djebbar
- Laboratory of Sciences and Technologies of the Environment (LSTE), University of Constantine, Constantine, Algeria
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Larouk S, Ouargli R, Shahidi D, Olhund L, Shiao TC, Chergui N, Sehili T, Roy R, Azzouz A. Catalytic ozonation of Orange-G through highly interactive contributions of hematite and SBA-16 - To better understand azo-dye oxidation in nature. CHEMOSPHERE 2017; 168:1648-1657. [PMID: 27939664 DOI: 10.1016/j.chemosphere.2016.11.120] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 06/06/2023]
Abstract
Hematite-SBA-16 mixture (HS) exhibited high catalytic activity in Orange-G (OG) ozonation in water. Total OG discoloration was achieved in half the time required with hematite or SBA-16 alone, all UV-Vis bands disappeared in less than 2 min. Liquid chromatography- Mass spectrometry (LC-MS) revealed that OG ozonation triggers via both hydroxylation and desulfonation of the aromatic rings into specific intermediates. Prolonged ozonation in the presence of hematite and SBA-16 alone resulted in different distributions of common derivatives. The latter were not detected after 25 min ozonation with HS. Stochastic modeling of the evolution in time of the UV-Vis bands of OG revealed strong binary interaction between the initial pH and catalyst concentration. This was explained in terms of reciprocal contributions of: i. the catalytic properties of hematite in spite of its low porosity; ii. the high specific surface area of SBA-16 for adsorption and surface reaction notwithstanding its low intrinsic catalytic activity. The weak basicity of SBA-16 surface seems to play a key-role in adsorption. These findings are of great interest for envisaging flexible oxidative treatments, where Fe3+ containing soils or mixtures of sand and rust may also act as catalyst for total mineralization of various azo-dyes, regardless to their structures.
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Affiliation(s)
- Safa Larouk
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C-3P8, Canada; Laboratory of Science and Technology of Environment, University of Constantine-1, Algeria
| | - Rachida Ouargli
- Department of Materials Engineering, University of Science and Technology, Oran, Algeria; Laboratory of Materials Chemistry, Oran University, BP 1524 El M'naouer, Oran, Algeria
| | - Dariush Shahidi
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C-3P8, Canada
| | - Leanne Olhund
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C-3P8, Canada
| | - Tze Chieh Shiao
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C-3P8, Canada
| | - Nacira Chergui
- Laboratory, Mechanical Engineering Department, École de Technologie Supérieure, H3C 1K3, Canada
| | - Tahar Sehili
- Laboratory of Science and Technology of Environment, University of Constantine-1, Algeria
| | - René Roy
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C-3P8, Canada
| | - Abdelkrim Azzouz
- Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C-3P8, Canada.
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Lavandier R, Quinete N, Hauser-Davis RA, Dias PS, Taniguchi S, Montone R, Moreira I. Polychlorinated biphenyls (PCBs) and Polybrominated Diphenyl Ethers (PBDEs) in three fish species from an estuary in the southeastern coast of Brazil. CHEMOSPHERE 2013; 90:2435-2443. [PMID: 23211324 DOI: 10.1016/j.chemosphere.2012.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 10/22/2012] [Accepted: 11/04/2012] [Indexed: 06/01/2023]
Abstract
Polychlorinated biphenyls (PCBs) and Polybrominated Diphenyls Ethers (PBDEs) are two highly lipophilic classes of persistent organic pollutants able to resist degradation and with the ability to bioaccumulate through the food chain. In Brazil, there are still few studies on PCBs and PBDEs in aquatic organisms. In this study, we determined the levels of PBDEs and PCBs in three different fish species from the Ilha Grande Bay, located in the southern state of Rio de Janeiro, Brazil. PBDEs levels were very low, with values below the limit of quantification. PCBs concentrations ranged from 2.29 to 27.60 ng g(-1) ww in muscle and from 3.41 to 34.22 ng g(-1) ww in liver of the three investigated fish species. Significant positive correlations were established between PCBs concentration and fish biometric variables in mullet (length and lipid content) and a statistically significant change between seasons in croaker was observed.
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Affiliation(s)
- Ricardo Lavandier
- Department of Chemistry, Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Rua Marquês de São Vicente, 225, Gávea - Rio de Janeiro, RJ 22453-900, Brazil.
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Current Applications of GC-(Q)TOF and GC–HRMS for the Determination of Persistent Organic Pollutants in Water and Sediments Samples. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/b978-0-444-62623-3.00018-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Nácher-Mestre J, Serrano R, Portolés-Nicolau T, Hernández F, Benedito-Palos L, Pérez-Sánchez J. A reliable analytical approach based on gas chromatography coupled to triple quadrupole and time-of-flight mass analyzers for the determination and confirmation of polycyclic aromatic hydrocarbons in complex matrices from aquaculture activities. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:2075-2086. [PMID: 19504494 DOI: 10.1002/rcm.4120] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The potential of gas chromatography coupled to tandem mass spectrometry (GC/MS/MS) with a triple quadrupole analyzer (QqQ) has been investigated for the quantification and reliable identification of sixteen polycyclic aromatic hydrocarbons (PAHs) from the EPA priority list in animal and vegetable samples from aquaculture activities, whose fat content ranged from 5 to 100%. Matrices analyzed included fish fillet, fish feed, fish oil and linseed oil. Combining optimized saponification and solid-phase extraction led to high efficiency in the elimination of interfering compounds, mainly fat, from the extracts. The developed procedure minimized the presence of these interfering compounds in the extracts and provided satisfactory recoveries of PAHs. The excellent sensitivity and selectivity of GC/(QqQ)MS/MS in selected reaction monitoring (SRM) allowed to reach limits of detection at pg/g levels. Two SRM transitions were acquired for each analyte to ensure reliable identification of compounds detected in samples. Confirmation of positive findings was performed by GC coupled to high-resolution time-of-flight mass spectrometry (GC/TOFMS). The accurate mass information provided by GC/TOFMS in full acquisition mode together with its high mass resolution makes it a powerful analytical tool for the unequivocal confirmation of PAHs in the matrices tested. The method developed was applied to the analysis of real-world samples of each matrix studied with the result of detecting and confirming the majority of analytes at the microg/kg level by both QqQ and TOF mass spectrometers.
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Affiliation(s)
- Jaime Nácher-Mestre
- Research Institute for Pesticides and Water (IUPA), Avda Sos Baynat, s/n. University Jaume I, 12071 Castellón, Spain
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Fujita H, Honda K, Hamada N, Yasunaga G, Fujise Y. Validation of high-throughput measurement system with microwave-assisted extraction, fully automated sample preparation device, and gas chromatography-electron capture detector for determination of polychlorinated biphenyls in whale blubber. CHEMOSPHERE 2009; 74:1069-1078. [PMID: 19095281 DOI: 10.1016/j.chemosphere.2008.10.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 10/28/2008] [Accepted: 10/28/2008] [Indexed: 05/27/2023]
Abstract
Validation of a high-throughput measurement system with microwave-assisted extraction (MAE), fully automated sample preparation device (SPD), and gas chromatography-electron capture detector (GC-ECD) for the determination of polychlorinated biphenyls (PCBs) in minke whale blubber was performed. PCB congeners accounting for > 95% of the total PCBs burden in blubber were efficiently extracted with a small volume (20 mL) of n-hexane using MAE due to simultaneous saponification and extraction. Further, the crude extract obtained by MAE was rapidly purified and automatically substituted to a small volume (1 mL) of toluene using SPD without using concentrators. Furthermore, the concentration of PCBs in the purified and concentrated solution was accurately determined by GC-ECD. Moreover, the result of accuracy test using a certified material (SRM 1588b; Cod liver oil) showed good agreement with the NIST certified concentration values. In addition, the method quantification limit of total-PCB in whale blubbers was 41 ng g(-1). This new measurement system for PCBs takes only four hours. Consequently, it indicated this method is the most suitable for the monitoring and screening of PCBs in the conservation of the marine ecosystem and safe distribution of foods.
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Affiliation(s)
- Hiroyuki Fujita
- Department of Environmental Science for Industry, Ehime University, 3-5-7 Tarumi Matsuyama, Ehime 790-8566, Japan.
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Fajar N, Carro A, Lorenzo R, Fernandez F, Cela R. Optimization of microwave-assisted extraction with saponification (MAES) for the determination of polybrominated flame retardants in aquaculture samples. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2008; 25:1015-23. [DOI: 10.1080/02652030801905435] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Yarita T, Aoyagi Y, Numata M, Takatsu A. Evaluation of supercritical fluid extraction for isotope dilution gas chromatography-mass spectrometric quantification of polychlorinated biphenyls in sediment. ANAL SCI 2006; 22:1449-54. [PMID: 17099277 DOI: 10.2116/analsci.22.1449] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Supercritical fluid extraction (SFE) has been evaluated as an extraction technique for the isotope-dilution quantification of polychlorinated biphenyls (PCBs) in a sediment sample. A high-resolution mass-spectrometric system equipped with a gas chromatograph was employed for the determination of seven target PCB congeners. The effect of the operation parameters on the SFE efficiency was investigated, in which the analytical values of five target PCB congeners significantly increased with increases in the extraction temperature and pressure, and that of 4,4'-dichlorobiphenyl further increased by applying static extraction. The following conditions were found to be optimal: extraction temperature, 140 degrees C; pressure, 30 MPa; time and mode, static for 15 min then dynamic for 30 min. Under these conditions, the addition of modifiers influenced the extraction of polar compounds, but did not affect the analytical values of the PCB congeners. The optimized method was suitable for high-throughput analysis as well as for providing accurate analytical results, which were comparable to or better than the analytical results obtained by Soxhlet extraction.
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Affiliation(s)
- Takashi Yarita
- National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba.
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Numata M, Yarita T, Aoyagi Y, Tsuda Y, Yamazaki M, Takatsu A, Ishikawa K, Chiba K, Okamaoto K. Sediment certified reference materials for the determination of polychlorinated biphenyls and organochlorine pesticides from the National Metrology Institute of Japan (NMIJ). Anal Bioanal Chem 2006; 387:2313-23. [PMID: 17019581 DOI: 10.1007/s00216-006-0691-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Revised: 07/12/2006] [Accepted: 07/17/2006] [Indexed: 11/25/2022]
Abstract
Two marine sediment certified reference materials, NMIJ CRM 7304-a and 7305-a, have been issued by the National Metrology Institute of Japan in the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) for the determination of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). The raw materials of the CRMs were collected from a bay near industrial activity in Japan. Characterization of these CRMs was conducted by NMIJ, where the sediments were analyzed using multiple analytical methods such as pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), saponification, Soxhlet extraction, supercritical fluid extraction (SFE), and ultrasonic extraction; the target compounds were determined by one of the primary methods of measurements, isotope dilution-mass spectrometry (ID-MS). Certified values have been provided for 14 PCB congeners (PCB numbers 3, 15, 28, 31, 70, 101, 105, 138, 153, 170, 180, 194, 206, 209) and 4 OCPs (gamma-HCH, 4,4'-DDT, 4,4'-DDE, 4,4'-DDD) in both CRMs. NMIJ CRM 7304-a has concentrations of the contaminants that are a factor of 2-15 greater than in CRM 7305-a. Both CRMs have information values for PCB homolog concentrations determined by collaborative analysis using a Japanese official method for determination of PCBs. The total PCB concentrations in the CRMs are approximately 920 and 86 microg kg(-1) dry mass respectively.
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Affiliation(s)
- Masahiko Numata
- Organic Standards Section 2, National Metrology Institute of Japan (NMIJ), AIST, 1-1-1, Umezono, Tsukuba, Ibaraki, 305-8563, Japan
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