Development of a New Determination Method for Indoxacarb Residue and Its Degradation Product

Günümüzde özellikle son 20 yıl süresince kullanımı çarpıcı bir şekilde artan pestisitler, modern tarımda böcekler, yabani otlar, mikroorganizmalar gibi zararlıları kontrol altına almak ve ürün verimini arttırmak için kullanılmakta olup hedef olmayan su, toprak ve gıdaları kirletmelerinin yanı sıra insan, evcil hayvanlar, bal arıları ve kuşlar için potansiyel sağlık riski gösterebilmektedirler. Zehirli olmalarının yanı sıra aynı zamanda bu bileşikler kanser yapıcı oluşumlara da sebep olurlar. Böceklerin ve yabani otların bu kimyasallara olan dayanıklılığının artması sonucu dünya çapında pestisit kalıntı problemlerine yol açan daha fazla pestisit geliştirilmiş ve daha yüksek dozlarda kullanılmaya başlanmıştır. Bununla birlikte pestisitler, besin zincirine çeşitli yollarla girerek canlıların vücutlarında biyolojik birikime uğramakta ve bu besin zincirinde ilerlerken her aşamada daha büyük miktarlara erişmektedirler. Balın da arasında bulunduğu gıdalar başta olmak üzere birçok matristeki pestisitlerin analizinin yapılması canlıların ona ne oranda maruz kaldığının doğru bir şekilde değerlendirilmesi bakımından büyük bir önem arz etmektedir. Bu nedenle pestisitlere ait kalıntı seviyelerinin tespiti ve kullanılan metotların güncel mevzuatlarda yer alan tolere edilebilir kalıntı konsantrasyonları da kapsaması beklenmektedir. Son yıllarda bu alanda bazı çalışmalar yapılmış olmasına rağmen ülkemizde ballardaki pestisit tayinleriyle ilgili çok az çalışma bulunmaktadır. Çalışmamızda bal örneklerinde İndoksakarb ((S)-7-kloro-3-[meteksikarbonil-(4-trifluorometoksi-fenil)-karbamoil]-2,5-dihidro-indeno[1,2-e][1,3,4]oksadiazin-4a(3H)-karboksilik asit metil esteri) kalıntısının ve bozunma ürününün belirlenmesi için yeni bir yöntem geliştirilmiştir. Diklorometan ile ekstraksiyon sonrasında, Gaz kromatograf-kütle Spektrometresi kullanılarak indoksakarb ve bozunma ürününü tayin edilmiştir. Geliştirilen metota ait geri kazanım yüzdesi, tespit ve tayin sınırları sırasıyla %78,7±5,5 ; 0,03 mg/kg ve 0,11 mg/ kg olarak hesaplanmıştır. İndoksakarb ile kirletilmiş kestane, çiçek, çam ve ayçiçek balı numuneleri 3 farklı sıcaklıkta 8 ay süresince izlenmiş ve beşinci ayda 4-(trifluorometoksi)fenil izosiyanat, literatürde belirtilenlerden farklı bir bozunma ürünü olarak tespit edilmiştir.Today pesticides, which have increased dramatically over the last 20 years, modern agriculture is used to control pests such as insects, weeds, microorganisms and to increase crop yields, but they pollute non-target water, soil and food, and can also present potential health risks for humans, domestic animals, honey bees and birds. Besides being toxic, they are also cause of cancerous formations. as a result of increasing resistance of insects and weeds to these chemicals, more pesticides have been developed worldwide and have begun to be applied to higher doses. In addition, pesticides enter the food chain in a various way, bioaccumulating in the bodies of living beings and reaching large quantities at each stage as they travel through this food chain.The analysis of pesticides in most of the matrices, especially the foodstuffs, including honey, including honey, is of great importance in terms of correctly assessing how the living beings are exposed to it. For this reason, it is expected that the residue levels of pesticides and the methods used will also include tolerable residue concentrations in current legislation. although there have been some studies in this area in recent years, there are very few studies on pesticide determination in our country.In our study, a new method was developed to determine the residues of Indoxacarb ((S)-7-chloro-3-[methoxycarbon yl-(4-trifluoromethoxy-phenyl)- carbamoyl]-2,5-dihydro-indeno[1,2-e][1,3,4]oxadiazine-4a(3H)- carboxylic acid methyl ester) and its degradation product in honey samples. after extraction with dichloromethane, Indoxacarb and its degradation product were determined using Gas Chromatograph-Mass Spectrometry. The percent recovery, detection and detection limits of the developed method were 78.7±5.5%; 0.03mg/kg and 0.11 mg/kg, respectively. Samples of chestnut, flower, pine and sunflower honey spiked with indoxacarb were observed at 3 different temperatures for 8 months, and in the fifth month 4- (trifluoromethoxy) phenyl isocyanate was identified as a degradation product different from the ones mentioned in the literature

Nutrient dynamics and eutrophication in the Sea of Marmara: Data from recent oceanographic research

This work was implemented to study the physicochemical and biological characteristics of the Sea of Marmara and the Turkish straits (TSS: Bosporus and Dardanelles straits) for the period 2010-2013 and to calculate winter and summer fluxes of nutrients (nitrates, phosphates) between the Aegean and Black Seas through the TSS. The brackish Black Sea waters reach the Dardanelles Strait with modified biochemical properties. The salinity and phosphates of the surface waters increased westwards. Biologically labile nutrients of Black Sea origin are utilized through biological processes in the Marmara Sea. On the other hand, increase of nutrients due to land based sources has led to eutrophication problems in the area. The sub surface water layer of Mediterranean origin is oxygen depleted (saturation < 30%) and rich in nutrients. Higher oxygen values indicated water mixing of the Sea of Marmara during winter 2012. Ammonium was the predominant form of inorganic nitrogen. The study area has been classified from Moderate to Bad trophic status. Izmit Bay also faced serious eutrophication problems together with hypoxic conditions below the halocline. Nutrient fluxes through the TSS showed temporal variation in the upper and lower layers related to changes in both nutrient concentrations and the water mass volume fluxes. Surface nitrates and phosphates outflux from the Sea of Marmara to the Aegean Sea was higher than the influx from the Black Sea through Bosporus strait, indicating high enrichment of nutrients in the Sea of Marmara from anthropogenic sources. (C) 2017 Elsevier B.V. All rights reserved

Synthesis and photoluminescence of LiCaBO3: M (M: Pb2+ and Bi3+) phosphor

Pure, Pb2+ and Bi3+ doped LiCaBO3 materials were prepared by a solution combustion synthesis method. The phase of LiCaBO3 were determined using the powder XRD and FTIR. The photoluminescent properties of Pb2+ and Bi3+ doped LiCaBO3 materials were investigated using spectrofluorometer at room temperature. The emission bands of LiCaBO3: Pb2+ and LiCaBO3: Bi3+ were observed at 296 and 378 nm, respectively. LiCaBO3 with different Pb2+ and Bi3+ doping concentrations were analyzed at room temperature. The Stokes shifts of LiCaBO3: Pb2+ and LiCaBO3: Bi3+ were calculated to be 3952 and 6440 cm(-1), respectively. (C) 2012 Elsevier B.V. All rights reserved

Stimuli-responsive smart nanoparticles with well-defined random and triblock terpolymers for controlled release of an anticancer drug

Stimuli-responsive nanoplatforms have shown great potential especially in efficient drug release systems. The rate of the anticancer drug release, adverse side effects, and toxicity can be controlled by designing nanoplatforms. Herein, mesoporous hydroxyapatite (HAp) nanoparticles were prepared. Fluorescent and pH-responsive biocompatible well-defined polymer chains were covalently attached by one step and sequential surface-initiated ATRP. The diameter of HAp increased from 120 to 147 and 158 nm with copolymerization. Polyethyleneglycol, poly(dimethylamino)propyl methacrylamide), and poly(fluorescent methacrylate) chains enhanced stimuli responsiveness of drug delivery. The drug release of the DOX@HAp/terpolymer nanoparticles was low under physiological conditions (pH 7.4). However, the release rate of DOX increased when pH was decreased to 5.5. The results of cytotoxicity indicated that the DOX-loaded HAp/terpolymer nanoparticles exhibited high biocompatibility and also caused apoptosis of cancer cells

Recovery of Au(III) ions by Au(III)-imprinted hydrogel

A new Au(III)-imprinted hydrogel (Au(III)-Imp) was prepared by the photopolymerisation of 4-acryloylmorpholine (AcM), 2-hydroxyethyl acrylate (HEA), and poly(ethylene glycol) diacrylate (cross-linking monomer, PEG-DA) in the presence of gold ions. In addition, non-imprinted hydrogel (N-Imp) was similarly prepared without Au(III) ions The Au(III)-Imp hydrogel was characterised by several techniques. To achieve the optimal conditions, effect of pH, time, and initial metal ion concentrations were investigated using a batch system. The pre-concentration factor for Au(III) ions was found to be at least 100. The analytical parameters of the method were determined and the method was also successfully applied to computer circuit board scrap samples. The reusability of the Au(III)-Imp hydrogel was also determined. (C) 2016 Institute of Chemistry, Slovak Academy of Science

Development of photopolymerized fluorescence sensor for glucose analysis

The sensing membrane was prepared by photopolymerization of 4-vinylphenylboronicacid (VPBA), hydroxyethylmethacrylate (HEMA) and poly(ethylene glycol) diacrylate (PEG-DA). The membran is capable of determining glucose between 2.78 x 10(-4) mM and 5.56 x 10(-3) mM with a limit of detection of 0.89 x 10(-5) mM, and limit of quantification 3.17 x 10(-3) mM (n = 7). It can be completely regenerated by using distilled water. The sensor performance characteristics such as response time, dynamic working range and sensitivity were reported. The proposed sensor was then applied successfully for the determination of glucose in blood samples. The optical sensor was stable, cost effective, easy to prepare, rapid and simple for the determination of glucose. (C) 2013 Elsevier B.V. All rights reserved

A novel polymer based fluorimetric sensor for fast and selective determination of chlorpyrifos

In this study, a spectrofluorometric method has been developed for the determination of chlorpyrifos. For this purpose, firstly, a polymer based membrane has been prepared for chlorpyrifos determination and parameters such as pH, calibration range, sensitivity, selectivity, sensitivity, response time and reproducibility were systematically investigated following the characterization of the membrane. Chlorpyrifos, an organophosphorus pesticide, can be determined by our sensor using the maximum excitation and emission wave lengths at 376 nm and 422 nm, respectively. The measurements can be completed within 20 s and the method also has a very low detection limit of 4.44 ? 10-10 mol L-1. Moreover, the developed polymeric Chlorpyrifos sensor is also suitable for the analysis of chlorpyrifos in tap water and pollen real samples

UV photocrosslinked polymeric fluorescent sensor for bisphenol A

Bisphenol A (BPA) is known as endocrine disrupting compound and it is widely used as an intermediate in manufacturing of polycarbonate and epoxy resins. These resins are used to manufacture inner surface of food cans or directly contact with food and can release BPA into food. It is known that BPA poses health risk, but how risky is a matter of debate. In this study, selective and sensitive fluorescent polymeric membrane sensor for detection of BPA was developed based on fluorescence quenching (lambda ex/lambda em = 272/295 nm). Working concentration range was linear between 4.4 x 10(-9) mol L-1 and 1.1 x 10(-7) mol L-1 with a detection limit of 1.58 x 10(-9) mol L-1. Optimization of sensor was done and the sensor exhibited satisfactory results for being used as a fluorescent sensor for determination of BPA. Additionally, the proposed method was successfully applied to plastic food containers real samples. The developed sensor was shown to be more sensitive than other methods currently in use, and was able to provide results in a matter of seconds, opening up the possibility of a rapid tool for BPA detection

Uptake of Pb2+ Using N-Vinyl Imidazole Based Uniform Porous Hydrogels

The uniform porous and continuous phase lead (II) adsorbent hydrogel, was prepared by copolymerizing 2-hydroxyethyl methacrylate (HEMA), acrylic acid (AAc), and N,N'-methylenebisacrylamide (MBAAm), with n-vinyl imidazole (VIM). A series of hydrogels, including different ratios of VIM, were prepared by photopolymerization and characterized. The influence of the uptake conditions such as pH, functional monomer percent, contact time, initial feed concentration, and foreign metal ions on the metal ion binding capacity of hydrogel, were also tested. The selective chelation of heavy metal ions from synthetic wastewater was also studied. The affinity order on molar basis was observed as follows: Pb (II) > Zn (II) > Cd (II). Chelation behavior of heavy metal ions could be modelled using both the Langmuir and Freundlich isotherms and it was seen that the Langmuir isotherm model was the best fit for the adsorption of Pb (II) ions in P(VIM/AAc/HEMA) hydrogel. Moreover, the limits of detection and the quantification values were determined. Regeneration of the hydrogels was easily performed with 1M HCl and the same hydrogel can be reused five times almost without any loss of adsorption capacity. All these features make P(VIM/AAc/HEMA) hydrogels potential candidate adsorbent for heavy metal removal