Pesticide analysis and method validation with GC/MSD instrument in environmental water samples

Bu çalışmada, su numunelerinde 130'dan fazla pestisit kalıntısının ppb (μg/L) düzeyinde belirlenmesinde kullanılabilecek hızlı ve çoklu bir analiz yöntemi önerilmiştir. Bu amaçla, analit konsantrasyonunun zenginleştirilmesi için bir Kuderna-Danish Evaporatif Konsantratör ve SIM (Selective Ion Monitoring) modunda çalışan gaz kromotografisi (GC) ile birleştirilmiş kütle spektrometresinin (MSD) kullanıldığı bir yöntem geliştirildi ve çoklu pestisit analizi için validasyonu yapıldı. Kromatografik analizde, pestisitlerin düşük konsantrasyonlarda dahi yüksek hassasiyetle tespit edilebilmesi gerektiğinden dolayı 30m HP-5 MS UI kapiler GC kolonu kullanıldı. Geliştirilen yöntemle miktar tayin limitleri 1.8 ve 29.2 ng.L-1 olarak belirlendi. Yöntem, bileşiklerin çoğunda sırasıyla 10 ppb ve 50 ppb seviyeleri için 70.1-116.5 % ve 70.7 – 114.0% aralıklarında ortalama geri kazanım sağladı. Pestisitlerin birbirinden çok farklı kimyasal yapıları, analizi yapılan tüm bileşikler için iyi bir geri kazanım sağlamayı zorlaştırmış olmasına rağmen sonuçların hassasiyetinin mükemmel olduğu değerlendirilebilir. Metodun seçiciliği, hesaplama ve tanımlama iyonlarının bağıl oranı yoluyla değerlendirildi ve değerlendirme sonucunda yeterli kabul edildi. Gerçek numunelerdeki analizler, enstrümantal yeterlilik kriterlerini ve sistem uygunluğu değerlendirmesini karşılamıştır. Böylelikle, 130 pestisitin nitel ve nicel tayinleri yapılmıştır.In this study, a rapid and multiple method has been proposed which can be used in determination of more than 130 pesticide residues at ppb (μg/L) level in water samples. For this purpose, a Kuderna-Danish Evaporative Concentrator, which was used for enrichment of the analyte concentration in the samples and gas chromatography coupled mass spectrometry in the selective ion monitoring (SIM) mode was developed and validated for the multi-class determination of pesticides. In the analysis, a 30m HP-5 MS UI capillary GC columns was used. The high sensitivity of chromatographic analysis was necessary, due to that these pesticides must be determined at low concentrations. The method presented quantification limits between 1.8 and 29.2 ng.L-1 . Most of the compounds presented mean recoveries between 70.1-116.5 % and 70.7 – 114.0% at 10 ppb and 50 ppb levels, respectively. Although the difference in chemical natures of the pesticides made difficult to attain good recovery for all of the compounds evaluated, the precision of the results was excellent. The selectivity of the method was evaluated through the relative intensity of quantification and qualification ions and was considered adequate. Analysis in real samples met criteria for instrumental qualification and the system suitability evaluation. Thus, qualitative and quantitative determinations of 130 pesticide were done

Gene level concurrency in genetic algorithms

This study describes an alternative concurrency approach in genetic algorithms. Inspiring from implicit parallelism in a physical chromosome, a vertical concurrency is introduced. Proposed gene process model allows genetic algorithms work in encodings independent from the gene position ordering in a chromosome. This feature is used to implement a gene reordering version of genetic algorithm. Further possible models of flexible gene position encodings are discussed

A building block favoring reordering method for gene positions in genetic algorithms

This work proposes an algorithm to speedup convergence of genetic algorithms that is based on the investigation of neighbouring gene values of the successful individuals of the chromosome pool. By performing some statistical inference on neighbour gene values, coherent behaving genes are detected. It is claimed that those coherent acting genes are belonging to the same building block that leads to the solution. It is desirable to keep genes of the same building block together to let them —probabilistically—live together in next generations. Therefore, a reordering of the gene positions is performed, periodically. The proposed algorithm is implemented for a minimum area non-overlapping rectangle placement problem and results are compared to a classical GA implementation

Bazı Kozmetik Ürünlerde Ağır Metal (Pb, Cd) Tayini

Özet: İlk insandan bu yana güzel görünmek, güzel kalmak insanlar için son derece önemli olmuştur. Günümüzde de kozmetik ürünlere yoğun bir ilgi vardır. Fakat bu ilgi artışı kozmetik ürünlerin güzelleştirirken, sağlığı tehdit edip etmediği sorusunu gündeme getirmektedir. Çünkü basit bir el kremi bile çok sayıda kimyasal içermekte ve bu kadar kimyasalın bir arada kullanıldığı ürünler, kullanım miktarı ve sıklığına bağlı olarak sağlığı tehdit etme ihtimali taşımaktadır. Bu kimyasallar içerisinde ağır metaller önemli bir yer teşkil etmektedir. Bu çalışmada amaç; bazı kozmetik ürünlerdeki ağır metallerin varlığının ve miktarlarının belirlenmesidir. Çalışma çerçevesinde piyasadan temin edilen farklı marka ve renklerde 10 adet saç boyası ve 10 adet ojede Atomik Absorpsiyon Spektroskopi (AAS) cihazında grafit fırın tekniği kullanılarak bazı ağır metallerin (Pb, Cd) tayini yapılmıştır. Sonuçlara göre; incelenen saç boyası ve ojelerde Pb ve Cd bulunduğu belirlenmiştir. Anahtar Kelimeler: Kozmetik, ağır metal, kurşun, kadminyum, saç boyası, oje. Determination of Heavy Metals (Pb, Cd) in Some Cosmetic Products Abstract: The seem beautiful, staying nice have been extremely important for the people for ages. Today demand for cosmetic products is increasing. But this interest brings up a question that cosmetics are dangerous for health or not. Because even a simple hand cream contains a large number of chemical and this products threaten the health depending on the amount and frequency of use. These chemicals have a high percentage of heavy metals. Purpose of the study, determination of heavy metals and their amounts in some cosmetics. We bought different brands and colored ten hair dyes and ten nail polishes from public market. Then we analyze some heavy metals (Pb, Cd) with Atomic Absorbsion Spektrometer (AAS). According to the results we determined lead and cadmium in these hair dyes and nail polishes. Keywords: Cosmetic, heavy metal, lead, cadmium, hair dye, nail polis

Assessment of Volatile Oil Composition, Phenolics and Antioxidant Activity of Bay (Laurus nobilis) Leaf and Usage in Cosmetic Applications

In this study, the components of the volatile oil obtained from Laurus nobilis leaves by steam distillation were determined using Agilent 6890 Gas Chromatography (GC) - 5975 Mass Spectrometry (MS). The antioxidant activities of different extracts of L. nobilis leaves were determined by using DPPH• (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity, β-carotene-linoleic acid bleaching assay and ABTS•+ (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) cation radical decolorization assay. Determination of the total phenolic contents of L. nobilis leaf extracts were performed using the Folin-Ciocalteau procedure and total flavonoid contents were measured using a spectrophotometric assay. According to the GC/MS results, 1,8-cineole (46.16%), alpha-terpinyl acetate (10.62%), alpha-pinene (6.27%), terpinen-4-ol (5.07%) and sabinene (4.99%) were found to be the major compounds in volatile oil. The obtained volatile oil was used to make skin care lotion. Stability tests and organoleptic analyses of final product were performed after 1, 5, 30 and 90 days of production. The highest amounts of total flavonoid content were found to be 5.48 ± 0.65 and 8.60 ± 0.12 µg QEs/mg in ethyl acetate and ethanol extracts, respectively. The highest amounts of total phenolic compounds were found to be 54.42 ± 0.14 and 25.32 ± 0.10 µg PEs/mg in ethyl acetate and ethanol extracts, respectively. According to the results of ABTS•+, DPPH• and β-carotene linoleic acid assays, ethyl acetate extract was found to be the most active extract (24.98±0.87 µg mL-1, 75.65±0.77 µg mL-1 and 19.32±1.04 µg mL-1)

Gene Level Concurrency in Genetic Algorithms

Abstract. This study describes an alternative concurrency approach in genetic algorithms. Inspiring from implicit parallelism in a physical chromosome, a vertical concurrency is introduced. Proposed gene process model allows genetic algorithms work in encodings independent from the gene position ordering in a chromosome. This feature is used to implement a gene reordering version of genetic algorithm. Further possible models of flexible gene position encodings are discussed.

Investigation of phenolic profiles and antioxidant activities of some Salvia species commonly grown in Southwest Anatolia using UPLC-ESI-MS/MS

Abstract Aerial parts of Salvia albimaculata Hedge & Hub.-Mor., Salvia potentillifolia Boiss & Heldr. ex Bentham. and Salvia nydeggeri Hub.-Mor. from Soutwest Anatolia, Turkey were evaluated to determine their phenolic compounds and antioxidant properties. According to the ultra performance liquid chromatography with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) analysis results, caffeic acid (3582.8 ± 2.5 μg/g, 2956.5 ± 4.6 μg/g and 2457.7 ± 3.1 μg/g) and 3,4-dihydroxy benzoic acid (1846.2 ± 3.1 μg/g, 2019.1 ± 2.2 μg/g and 1901.3 ± 1.5 μg/g) were found to be in the highest concentrations in S. potentillifolia, S. albimaculata and S. nydeggeri, respectively. Total amounts of phenolics and flavonoids were determined highest in ethyl acetate extracts of samples and varied from 62.4 ± 0.1 to 55.4 ± 0.0 µg PEs/mg and from 296.8 ± 1.4 to 198.4 ± 1.5 µg QEs/mg, respectively. Antioxidant activity of S. potentillifolia was found to be higher than the others for ABTS•+ and β-carotene linoleic acid assays (SC50 = 49.8 ± 0.9 and IC50 = 26.1 ± 0.6 µg /mL, respectively) while S. albimaculata was found to be higher for DPPH• assay (SC50 = 227.4 ± 1.1 µg/mL)

A pattern classification approach for boosting with genetic algorithms

Ensemble learning is a multiple-classifier machine learning approach which produces collections and ensembles statistical classifiers to build up more accurate classifier than the individual classifiers. Bagging, boosting and voting methods are the basic examples of ensemble learning. In this study, a novel boosting technique targeting to solve partial problems of AdaBoost, a well-known boosting algorithm, is proposed. The proposed system finds an elegant way of boosting a bunch of classifiers successively to form a “better classifier” than each ensembled classifiers. AdaBoost algorithm employs a greedy search over hypothesis space to find a “good” suboptimal solution. On the hand, the system proposed employs an evolutionary search with genetic algorithms instead of greedy search. Empirical results show that classification with boosted evolutionary computing outperforms the classical AdaBoost in equivalent experimental environments