Records |
Author |
De Jong, M.; Florea, A.; de Vries, A.-M.; van Nuijs, A.L.N.; Covaci, A.; Van Durme, F.; Martins, J.C.; Samyn, N.; De Wael, K. |
Title |
Levamisole : a common adulterant in cocaine street samples hindering electrochemical detection of cocaine |
Type |
A1 Journal article |
Year |
2018 |
Publication |
Analytical chemistry |
Abbreviated Journal |
Anal Chem |
Volume |
90 |
Issue |
8 |
Pages |
5290-5297 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre |
Abstract |
The present work investigates the electrochemical determination of cocaine in the presence of levamisole, one of the most common adulterants found in cocaine street samples. Levamisole misleads cocaine color tests, giving a blue color (positive test) even in the absence of cocaine. Moreover, the electrochemical detection of cocaine is also affected by the presence of levamisole, with a suppression of the oxidation signal of cocaine. When levamisole is present in the sample in ratios higher than 1:1, the cocaine signal is no longer detected, thus leading to false negative results. Mass spectrometry and nuclear magnetic resonance were used to investigate if the signal suppression is due to the formation of a complex between cocaine and levamisole in bulk solution. Strategies to eliminate this suppressing effect are further suggested in this manuscript. In a first approach, the increase of the pH of the sample solution from pH 7 to pH 12 allowed the voltammetric determination of cocaine in the presence of levamisole in a concentration range from 10 to 5000 μM at nonmodified graphite disposable electrodes with a detection limit of 5 μM. In a second approach, the graphite electrode was cathodically pretreated, resulting in the presence of oxidation peaks of both cocaine and levamisole, with a detection limit for cocaine of 3 μM over the linear range of concentrations from 10 to 2500 μM. Both these strategies have been successfully applied for the simultaneous detection of cocaine and levamisole in three street samples on unmodified graphite disposable electrodes. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000430512200049 |
Publication Date |
2018-02-23 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0003-2700; 5206-882x |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.32 |
Times cited |
8 |
Open Access |
|
Notes |
; This project has received funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant Agreement No. 753223 Narcoreader. This work was also supported by BR/314/PI/ APTADRU Project and IOF-SBO (UAntwerp). Alexander van Nuijs acknowledges the Research Foundation-Flanders (FWO) for his postdoctoral fellowship. ; |
Approved |
Most recent IF: 6.32 |
Call Number |
UA @ admin @ c:irua:149528 |
Serial ![sorted by Serial field, ascending order (up)](img/sort_asc.gif) |
5693 |
Permanent link to this record |
|
|
|
Author |
Alvarez-Martin, A.; Trashin, S.; Cuykx, M.; Covaci, A.; De Wael, K.; Janssens, K. |
Title |
Photodegradation mechanisms and kinetics of Eosin-Y in oxic and anoxic conditions |
Type |
A1 Journal article |
Year |
2017 |
Publication |
Dyes and pigments |
Abbreviated Journal |
Dyes Pigments |
Volume |
145 |
Issue |
|
Pages |
376-384 |
Keywords |
A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre |
Abstract |
Lakes based on Eosin-Y are extensively used by 19th century artists. Unfortunately, the identification of these pigments in paintings is a difficult task because Eosin-Y degrades very fast under the influence of light. The characterization of the (photo)degradation products of Eosin-Y can be very useful for the identification of these pigments in historic works of art and related cultural heritage artifacts. Furthermore, knowledge on how different factors influence the discoloration process (e.g. different types of irradiation sources and presence/absence of oxygen) is a valuable tool for preventive conservation. To this aim we performed a study on the photodegradation of Eosin-Y in solution under different illumination and in both oxic and anoxic conditions. The photodegradation of Eosin-Y was monitored by UV-VIS spectrophotometry, LC-QTOFMS and electrochemistry techniques. Results indicated higher degradation rates, by a factor of 20 or higher, under illumination with wavelengths near to the main absorbance band of the red pigment. Two different degradation pathways are observed under the conditions studied. LC-QTOFMS and electrochemistry suggested that in the presence of oxygen the degradation mechanism is an oxidative process where the breakdown of the structure causes the total discoloration. Meanwhile under anoxic conditions, a debromination process takes place while the chromophore, and consequently the color of the molecule in solution, remains essentially intact. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000405972900046 |
Publication Date |
2017-06-16 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0143-7208 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.473 |
Times cited |
18 |
Open Access |
|
Notes |
; ; |
Approved |
Most recent IF: 3.473 |
Call Number |
UA @ admin @ c:irua:144385 |
Serial ![sorted by Serial field, ascending order (up)](img/sort_asc.gif) |
5770 |
Permanent link to this record |
|
|
|
Author |
Hellar-Kihampa, H.; De Wael, K.; Lugwisha, E.; Govindan, M.; Covaci, A.; Van Grieken, R. |
Title |
Spatial monitoring of organohalogen compounds in surface water and sediments of a rural-urban river basin in Tanzania |
Type |
A1 Journal article |
Year |
2013 |
Publication |
The science of the total environment |
Abbreviated Journal |
Sci Total Environ |
Volume |
447 |
Issue |
|
Pages |
186-197 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre |
Abstract |
The presence of persistent organic pollutants in Tanzanian environment is not well monitored despite the existing pollution potential from a number of sources. In this study, we investigated for the first time, the concentration profiles of different organohalogen compounds such as organochlorine pesticide residues (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in environmental samples (water and sediments) from the Pangani river basin (PRB). The PRB is one of the largest drainage basins in Tanzania, with its watershed exposed to multiple input sources of trace organic contaminants. Surface water and sediments were sampled from 12 representative stations of diverse characteristics and land-use practices, in three distinct seasons, and extracted by liquidliquid and Soxhlet extraction methods, respectively. Water samples were analyzed by GC-ECD for OCPs only, while sediment samples were analyzed for OCPs, PCBs and PBDEs by GC/MS. Seven compounds, dominated by HCH isomers (5104460 pg/L) and DDT analogs (1601460 pg/L),were detected in the water samples. These concentrations are far below the WHO guidelines for drinking water quality. A total of 42 compounds (8 OCPs, 28 PCB congeners and 6 PBDE congeners) were detected in the sediment samples. Their respective total concentration ranges were 24510,230; 35711,000 and 382175 pg/g dry weight. The spatial distribution patterns and Hierarchical Cluster Analysis reflected the impact of historical agricultural usage in sugarcane plantations (OCPs), and urbanization (PCBs and PBDEs). Risk assessment using sediment quality guidelines indicated no ecotoxicological risks. The results we have found provide preliminary data on levels of the organic contaminants in Pangani river basin as a new insight on the environmental quality of the area. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000317538100022 |
Publication Date |
2013-02-05 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0048-9697 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.9 |
Times cited |
42 |
Open Access |
|
Notes |
; This research project was funded by the International Foundation for Science (IFS, Project Number W/4945-1). The authors wish to acknowledge the contribution of the Pangani Basin Water Office (PBWO) in Moshi, Tanzania; especially Ms. Arafa Maggidi in provision of valuable information and assistance with the sampling campaigns, and Salim Lyimo in mapping of the study area. The contributions of Mr. Peter Machibya of the Department of Geology, University of Dar es Salaam, Tanzania in sediment characterization; and Mr. Emmanuel Gwae, of the Government Chemists Laboratory Agency (GCLA) Dar es Salaam, Tanzania, for instrumental analysis of the water samples, are highly appreciated. Harieth Hellar-Kihampa acknowledges financial support from the Belgian Technical Agency (BTC). Govindan Malarvannan and Adrian Covaci acknowledge financial support from the University of Antwerp. ; |
Approved |
Most recent IF: 4.9; 2013 IF: 3.163 |
Call Number |
UA @ admin @ c:irua:105260 |
Serial ![sorted by Serial field, ascending order (up)](img/sort_asc.gif) |
5836 |
Permanent link to this record |
|
|
|
Author |
Poma, G.; McGrath, T.J.; Christia, C.; Govindan, M.; Covaci, A. |
Title |
Emerging halogenated flame retardants in the indoor environment |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Comprehensive analytical chemistry |
Abbreviated Journal |
|
Volume |
88 |
Issue |
|
Pages |
107-140 |
Keywords |
A1 Journal article; Pharmacology. Therapy; Electron microscopy for materials research (EMAT); Toxicological Centre |
Abstract |
Indoor environments are considered an important contributor to external human exposure to halogenated flame retardants (HFRs) due to the large amounts of chemicals currently incorporated in indoor equipment and the time humans spend every day in indoor environments. In this chapter, the presence and use of novel brominated flame retardants (NBFRs), dechlorane plus (DPs), chlorinated organophosphorus flame retardants (Cl-PFRs) and chlorinated paraffins (CPs) in indoor dust, air and consumer products collected from different indoor microenvironments (homes, public indoor spaces, and vehicles) are discussed. While data on the concentrations of HFRs in indoor dust and air are widely available, figures are still scarce for consumer products, such as textiles and foams, furnishings, flooring, electric and electronic products and building materials. This knowledge gaps still represents the biggest obstacle in linking eventual sources of contamination to the presence and chemical patterns in indoor dust and air. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
|
Publication Date |
2019-11-22 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
978-0-444-64339-1 |
ISBN |
|
Additional Links |
UA library record |
Impact Factor |
|
Times cited |
|
Open Access |
OpenAccess |
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:168776 |
Serial ![sorted by Serial field, ascending order (up)](img/sort_asc.gif) |
6505 |
Permanent link to this record |
|
|
|
Author |
Dirtu, A.C.; Ravindra, K.; Roosens, L.; Van Grieken, R.; Neels, H.; Blust, R.; Covaci, A. |
Title |
Fast analysis of decabrominated diphenyl ether using low-pressure gas chromatography.electron-capture negative ionization mass spectrometry |
Type |
A1 Journal article |
Year |
2008 |
Publication |
Journal of chromatography : A |
Abbreviated Journal |
|
Volume |
1186 |
Issue |
|
Pages |
295-301 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000254884700024 |
Publication Date |
2007-07-23 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0021-9673 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
|
Open Access |
|
Notes |
|
Approved |
no |
Call Number |
UA @ admin @ c:irua:67546 |
Serial ![sorted by Serial field, ascending order (up)](img/sort_asc.gif) |
7957 |
Permanent link to this record |
|
|
|
Author |
Dirtu, A.C.; Cernat, R.; Dragan, D.; Mocanu, R.; Van Grieken, R.; Neels, H.; Covaci, A. |
Title |
Organohalogenated pollutants in human serum from Iassy, Romania and their relation with age and gender |
Type |
A1 Journal article |
Year |
2006 |
Publication |
Environment international |
Abbreviated Journal |
|
Volume |
32 |
Issue |
6 |
Pages |
797-803 |
Keywords |
A1 Journal article; Toxicological Centre; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000239095700012 |
Publication Date |
2006-06-11 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0160-4120 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
|
Open Access |
|
Notes |
|
Approved |
no |
Call Number |
UA @ admin @ c:irua:58916 |
Serial ![sorted by Serial field, ascending order (up)](img/sort_asc.gif) |
8347 |
Permanent link to this record |
|
|
|
Author |
Daems, D.; van Nuijs, A.L.N.; Covaci, A.; Hamidi-Asl, E.; Van Camp, G.; Nagels, L.J. |
Title |
Potentiometric detection in UPLC as an easy alternative to determine cocaine in biological samples |
Type |
A1 Journal article |
Year |
2015 |
Publication |
Biomedical chromatography |
Abbreviated Journal |
|
Volume |
29 |
Issue |
7 |
Pages |
1124-1129 |
Keywords |
A1 Journal article; Pharmacology. Therapy; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Toxicological Centre |
Abstract |
The analytical methods which are often used for the determination of cocaine in complex biological matrices are a prescreening immunoassay and confirmation by chromatography combined with mass spectrometry. We suggest an ultra-high-pressure liquid chromatography combined with a potentiometric detector, as a fast and practical method to detect and quantify cocaine in biological samples. An adsorption/desorption model was used to investigate the usefulness of the potentiometric detector to determine cocaine in complex matrices. Detection limits of 6.3ngmL(-1) were obtained in plasma and urine, which is below the maximum residue limit (MRL) of 25ngmL(-1). A set of seven plasma samples and 10 urine samples were classified identically by both methods as exceeding the MRL or being inferior to it. The results obtained with the UPLC/potentiometric detection method were compared with the results obtained with the UPLC/MS method for samples spiked with varying cocaine concentrations. The intraclass correlation coefficient was 0.997 for serum (n =7) and 0.977 for urine (n =8). As liquid chromatography is an established technique, and as potentiometry is very simple and cost-effective in terms of equipment, we believe that this method is potentially easy, inexpensive, fast and reliable. Copyright (c) 2014 John Wiley & Sons, Ltd. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Wos |
000356694000020 |
Publication Date |
2014-12-16 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0269-3879 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
|
Times cited |
|
Open Access |
|
Notes |
|
Approved |
no |
Call Number |
UA @ admin @ c:irua:127069 |
Serial ![sorted by Serial field, ascending order (up)](img/sort_asc.gif) |
8396 |
Permanent link to this record |