TURKISH JOURNAL OF CHEMISTRY

An evaluation was made of different digestion methods for the determination of arsenic and antimony in table salt samples prior to hydride generation atomic absorption spectrometric analysis. Microwave acid digestion, classical wet digestion, dry ashing, and fusion were applied to the decomposition of salt samples and optimum conditions were investigated. Samples were decomposed by changing heating time, digestion techniques, and the amount and composition of acid, and then the concentrations of arsenic and antimony in an unrefined salt sample were measured. It is concluded that microwave acid digestion decomposes salt samples with a very short heating time and with small amounts of reagents compared with the classical wet digestion methods, which require several hours for the heating step and several milliliters of reagents. The accuracy of the procedure was checked using pond sediment certified reference material. The proposed procedure was applied for the determination of arsenic and antimony in several table salt samples collected in. Izmir, Turkey, and the arsenic contents in the samples were found to be below the maximum permissible limits. Microwave digestion in combination with hydride generation atomic absorption spectrometry could be used routinely to monitor these metals in table salt samples

Selective and sensitive fluorimetric determination of carbendazim in apple and orange after preconcentration with magnetite-molecularly imprinted polymer

PubMed ID: 27886648In this study, magnetite-molecularly imprinted polymer has been used for the first time as selective adsorbent before the fluorimetric determination of carbendazim. Adsorption capacity of the magnetite-molecularly imprinted polymer was found to be 2.31 ± 0.63 mg g- 1 (n = 3). Limit of detection (LOD) and limit of quantification (LOQ) of the method were found to be 2.3 and 7.8 µg L- 1, respectively. Calibration graph was linear in the range of 10–1000 µg L- 1. Rapidity is an important advantage of the method where re-binding and recovery processes of carbendazim can be completed within an hour. The same imprinted polymer can be used for the determination of carbendazim without any capacity loss repeatedly for at least ten times. Proposed method has been successfully applied to determine carbendazim residues in apple and orange, where the recoveries of the spiked samples were found to be in the range of 95.7–103%. Characterization of the adsorbent and the effects of some potential interferences were also evaluated. With the reasonably high capacity and reusability of the adsorbent, dynamic calibration range, rapidity, simplicity, cost-effectiveness and with suitable LOD and LOQ, the proposed method is an ideal method for the determination of carbendazim. © 2016 Elsevier B.V.Ege Üniversitesi: 2013 FEN 037We gratefully thank to Research Fund of Ege University for financial support (Grant no: 2013 FEN 037 ). Appendix A -

Preconcentration and highly sensitive fluorimetric determination of Tin(IV) by using a novel nickel/nickel boride nanosorbent

A new nickel/nickel boride-based nanosorbent which provides high sorption efficiency for tin(IV) was developed in this study. The sorbent capacity was found to be 26.33 ± 2.18 mg tin(IV)/g sorbent (n = 3). Tin(IV) can be determined by measuring the fluorescence signal of the tin(IV)–flavonol complex. Recovery of tin(IV) with 1 mol/L hydrochloric acid was found to be 98.70 ± 1.29 (n = 5). The limit of detection and the limit of quantification of the method were found to be 0.5 and 1.7 µg/L, respectively. The calibration graph was linear in the range of 4–80 µg/L. The adsorption type was determined by using the adsorption isotherms. Interference effects of several metal ions on tin(IV) determination were investigated and the tolerable concentration limits of these metal ions were determined. The nickel/nickel boride nanosorbent reduces the interference effects and improves the sensitivity and the selectivity of the method. With the aid of the novel nanosorbent, higher tolerable concentration limits of interfering ions like molybdenum(VI), phosphate, and fluoride compared to the standard detection method were observed in this study. The proposed method was applied to canned tomato paste and canned corn. The novel nickel–nickel boride sorbent appears to be one of the sorbents with high capacity and enrichment factor. Characterization of the sorbent was investigated. © 2016, Copyright © Taylor & Francis Group, LLC

Development of rapid, sensitive and selective fluorimetric method for determination of 1-naphthalene acetic acid in cucumber by using magnetite-molecularly imprinted polymer

PubMed ID: 30954798In this study, a novel method based on the determination of 1-naphthalene acetic acid with the usage of magnetite-molecularly imprinted polymer prior to fluorimetric detection has been developed. Magnetite-molecularly imprinted polymer has been used for the first time as selective adsorbent for the determination of 1-naphthalene acetic acid. The adsorption capacity of the synthesized polymer was found to be 2.18 ± 0.36 mg g -1 (n = 3). Limit of detection (LOD) and limit of quantification (LOQ) of the method were found to be 0.75 and 2.50 µg L -1 , respectively. Linearity of the calibration graph for the proposed method was observed within the range of 20–700 µg L -1 . The proposed method seems to be rapid where the detection procedure for 1-naphthalene acetic acid can be completed within a total time of 1 h. The same imprinted polymer can be used for the determination of 1-naphthalene acetic acid with quantitative sorption and recovery values repeatedly for at least ten times. The effects of some potential organic interferences were investigated. Proposed method has been successfully applied to determine 1-naphthalene acetic acid in cucumber, where the recoveries of the spiked samples were found to be in the range of 93.7–104.5%. Characterization of the synthesized polymer was also evaluated. By combining the high capacity, cheapness, reusability and selectivity of the magnetic adsorbent with the dynamic calibration range, rapidity, simplicity, and sensitivity of fluorimetry, the proposed method seems to be an ideal method for the determination of trace levels of 1-naphthalene acetic acid. © 2019 Elsevier B.V.2018EGEMATAL002We gratefully thank to Research Fund of Ege University for financial support (Grant no: 2018EGEMATAL002 ). Appendix A -

Determination of arsenic leaching from glazed and non-glazed Turkish traditional earthenware

PubMed ID: 21669332Glazed and non-glazed earthenware is traditionally and widely used in Turkey and most of the Mediterranean and the Middle East countries for cooking and conservation of foodstuff. Acid-leaching tests have been carried out to determine whether the use of glazed and non-glazed earthenware may constitute a human health hazard risk to the consumers. Earthenware was leached with 4% acetic acid and 1% citric acid solutions, and arsenic in the leachates was measured using hydride generation atomic absorption spectrometry. Arsenic concentrations in the leach solution of non-glazed potteries varied from 30.9 to 800-gL-1, while the glazed potteries varied generally from below the limit of detection (0.5-gL-1) to 30.6-gL-1, but in one poorly glazed series it reached to 110-gL-1. Therefore, the risk of arsenic poisoning by poorly glazed and non-glazed potteries is high enough to be of concern. It appears that this is the first study reporting arsenic release from earthenware into food. © 2011 Elsevier B.V.The support of the Ege University Research Foundation is acknowledged with gratitude. We would like to thank Tülin Deniz Çiftçi and Onur Yayayürük for their contributions during this study. -

A highly sensitive and selective fluorescent sensor for the determination of copper(II) based on a schiff base

A highly sensitive and selective optical sensor for the determination of trace amounts of Cu2+ based on fluorescence quenching has been developed. The sensing membrane was prepared by immobilization of a novel fluorescent Schiff base ligand 4-(1-phenyl-1-methylcyclobutane-3-yl)-2-(2-hydroxy-5-romobenzylidene)aminothiazole, on polyvinlyl chloride. The novel sensor, which has a linear range of 1.0 × 10-8 - 5.7 × 10-4 mol L-1 for Cu2+ ions with a detection limit of 8.8 × 10-9 mol L-1 (0.56 µg L-1), is fully reversible and the response time (?90) was approximately 2.5 min. The optode was highly selective and can readily be regenerated by treatment with 10-2 mol L-1 HCl. The accuracy of the proposed sensor was confirmed by analyzing standard reference materials of natural water and peach leaves. The sensor was successfully applied for the determination of copper in tap water and tea samples. © 2009 Elsevier Ltd. All rights reserved